CLOCK CASES

A Practical Guide to their Construction, Restoration and Conservation

Nigel Barnes and Karoliina Ilmonen

First published in 2015 by
The Crowood Press Ltd
Ramsbury, Marlborough
Wiltshire SN8 2HR

www.crowood.com

This e-book published 2015

© Nigel Barnes and Karoliina Ilmonen 2015

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers.

British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.

ISBN 978 1 78500 024 9

Disclaimer

The practical workshop procedures and the tools and equipment used by those involved in clock case construction, restoration and conservation are potentially dangerous. All equipment and tools employed in this work should be used in strict accordance with both current health and safety regulations and the manufacturer’s instructions.

The author and the publisher do not accept any responsibility in any manner whatsoever for any error or omission, or any loss, damage, injury, adverse outcome, or liability of any kind incurred as a result of the use of any of the information contained in this book, or reliance upon it. If in doubt about any aspect of the construction, restoration and conservation of clock cases, readers are advised to seek professional advice.

Throughout this book ‘craftsman’, ‘he’, ‘him’ and ‘his’ are used as neutral pronouns and as such refer to males and females.

Photographs by Nigel Barnes except where otherwise stated.

Contents

Preface

Chapter 1  Introduction

Chapter 2  Woods and Woodworking in Clock Cases

Chapter 3  Some Special Techniques in Clock-Case Construction, Restoration and Conservation

Chapter 4  Making a New Clock Case

Chapter 5  A Clock-Case Restoration

Chapter 6  Some Wooden Clock Cases and Their Restoration

Chapter 7  Stone Clock Cases of the Nineteenth and Twentieth Centuries

Chapter 8  Metal Clock Cases of the Nineteenth and Twentieth Centuries

Chapter 9  Finding a Clock Case to Restore

Appendix: Guidelines for Restoring and Conserving Horological Objects

Index

Preface

This book is a sequel and companion to Maintaining Longcase Clocks – An Owner’s Guide to Maintenance, Restoration and Conservation and is likewise aimed at the amateur clock owner and the aspiring professional. While that book was restricted in its scope to just one type of clock, this is intended as a source for anyone working on clock cases. It covers the more frequent types of cases of clocks made up to about one hundred years ago or less – in other words, clock cases that would now be considered as antique in the usual meaning of the word. Because we work in conservation and restoration, we do not offer advice about modern designs for new clocks.

As the title suggests, this book is aimed at the practitioner – everyone from the amateur clock enthusiast to a professional horological service provider – rather than the collector. As a result, the historical background material provided is just enough to put the clock cases into their social and historical context or setting. Nevertheless, it is inevitable that we touch on the wider subject of how antiques and cultural heritage objects might be preserved for future generations to enjoy and learn from. Over the centuries, clocks and clock cases have been made to reflect a wide range of status, quality and value; the same sorts of value judgements and decisions about preservation and restoration that apply to other forms of cultural heritage object apply equally to clock cases.

My co-author in this book is Karoliina Ilmonen, a bright and energetic clock restorer and conservator. She has contributed modern thinking based on her formal training and comprehensive understanding of the principles of conservation in horology.

Karoliina and I are not museum-based conservators. We both provide professional services in the horological sector as clock and clock-case restorers and conservators, so we are familiar with the conflicts between available budget, preservation and usage. We often argue about how best to apply the principles of conservation and how to make those real-world compromises that will best suit our clients while, as far as possible, preserving the clocks that are temporarily entrusted to us. Karoliina is a theoretical perfectionist in her approach to her conservation work and I am more of a pragmatist, aware of the client’s budget and the foreseeable future. The fact that we do not always disagree indicates that, for any clock, a number of conservation or restoration approaches are possible, each with a separate outcome.

People have always been fascinated by old items and, with the rise of mass production in the early twentieth century, formalized ideas about conservation in general began to develop. The preservation of horological heritage was always a slightly different case because it was to some extent obstructed by a contrary groundswell of conservative, pragmatic clock-menders whose primary objective was the maintenance of domestic time-keeping by whatever means necessary.

Since those early conservation days, clock cases have remained in a sort of no-man’s land between the horology and antique furniture sectors. This advice given by the British Horological Institute in its 1995 publication, Conservation of Clocks and Watches (ed. Peter B. Wills), asserted that clock case restoration was a specialized field and that clock restorers who had no previous training or experience in that area should not become involved in it. From the other side of the fence, The British Antique Furniture Restorers’ Association lists clock movements and clock dials among its services – but not clock cases. Neither the European Confederation of Conservator-Restorers’ Organizations (ECCO) nor the UK Institute of Conservation (ICON) are aware of any conservation guidelines that are specific to clock cases. And, while the British Horological Institute recommends avoidance, the Antiquarian Horological Society offers a bursary for conservation work, but gives no conservation advice for clocks, let alone clock cases.

The apparent absence of specific guidance about clock-case restoration should not be a matter for immediate concern. Clock cases are, after all, cultural heritage objects for which universal guidelines apply. Drawing on as many sources as possible, our aim has been to set out clear practical advice that is straightforward to follow and will be more or less in harmony with the sorts of best-practice guidelines that will surely play an increasingly significant part in the way clock cases are preserved for future generations.

Conservation and restoration start with identification and historical assessment. To quote from Herbert Cescinsky, ‘The history of a nation’s handicrafts is the history of a people, and its art works mark the measure of its culture and education. With the furniture of the various periods we enter the homes of their everyday life.’

Although our book is more concerned with restoration and conservation, we accept that advice on making new clock cases is both necessary and appropriate. The reason for that apparent discrepancy is that conservators must consider the long-term preservation of clocks. In the case of a clock that has somehow lost its case, the preferred preservation route is the construction of an appropriate replacement case. This will ensure that the clock remains intact as an identifiable object and should also convey an impression or sense of the original.

We discuss the main types of clock case, referring to their historical background and evolutionary history before dealing with the specifics of construction and restoration. Clock cases made from materials other than wood figure quite prominently – this is an area that otherwise is only really covered by special interest groups, mostly through the internet.

The subject of clock cases is inseparable from the wider subject of clocks but we describe clock movements only in terms of physical characteristics, the dimensions and properties that influence the design and construction of their cases.

Regardless of classifications and formal definitions of the key terms ‘repair’, ‘restoration’, ‘conservation’ and ‘preservation’, fundamental uncertainties remain that are mostly related to the more basic definition of ‘horological heritage’. The introductory chapter examines the idea of how and why clocks and their cases come to be classed as ‘worthy of preservation’ or not, and how perceptions change, and will continue to change.

There is no reason why the amateur clock restorer should not aspire to the highest standards in terms of ethical approach, knowledge of the subject and workmanship, all of which are routinely applied by museum conservators. Ultimately, good restoration is in an owner’s best interest because it protects the value of his asset. Even the amateur who lacks years of experience can follow some really basic rules; one of the most important is to work on an antique clock case (or any antique object) in a way that the original maker would approve.

Amateur restoration is no longer limited by the cultural demarcations of previous generations when a clockmaker made only clocks and a chair-maker made only chairs. Craft skills are disappearing all over the developed world and, although the amateur can acquire the same skills through self-teaching, it takes time and practice. Our book can only guide the thoughts, not the hands, and we would encourage the interested reader to get together with like-minded people by joining a mutual interest group.

Nigel Barnes

Chapter 1

Introduction

BACKGROUND

Over the years a great many books have been written on the subject of clocks, dealing in detail with technical innovations about timekeeping and with the development of various clock types. Often, books are specific to one type of clock or, sometimes, to just one British county or region.

Inevitably, books about clocks contain some information about clock cases but usually in an incidental way and only a very few books have been written specifically about the subject. This might seem strange, since the outward appearance of a clock is likely to be a significant factor for a potential buyer. It seems even more strange when clocks are compared with antique furniture, where the superficial or decorative characteristics receive far more attention than the hidden details of the construction. Like antique furniture, clocks varied widely in terms of quality or status, with styles frequently changing or evolving to reflect prevailing fashions. The older examples tend to be more sought after, although old does not absolutely guarantee quality. It might, however, mean scarce.

Clocks made for the wealthy elite in the days before mass production were hand-crafted by highly skilled craftsmen. The carefully selected mahogany veneers and intricate gilded brass-work applied to the case of this three-fusée chiming clock are intended to give an impression of opulence. (Steve Daniels)

Ignoring clock cases in books about clocks has a historical precedent: one early book about clocks was written in the 1480s by a German monk working in the Vatican. The manuscript of Fra Paulus Almanus (Brother Paul the German), discovered in the twentieth century in a monastery library, contains quite detailed descriptions of thirty clocks. It seems that Brother Paul was a clock-mender and that his clients were the senior hierarchy of the church. Although there are a few tantalising clues about the clocks’ cases, the manuscript is a clock-mender’s record showing wheels, striking arrangements and other mechanical detail. Brother Paul the clock-mender was so focused on the mechanical parts of the thirty clocks that their cases must have seemed insignificant.

Although this book covers the cases made for mechanical clocks during a limited period – from the middle of the seventeenth century to the beginning of the twentieth century – the clocks within that time span represent a very wide variety of size, form and status. The term ‘status’ is significant; largely overlooked within the clock and antique trades, it is an indicator of the classes that existed within society and the position within those social strata of the first owner.

When the English monarchy was restored in the year 1660, following a short experimental republic, wealth was concentrated in the hands of a very small proportion of the population. Being hand-made, clocks were very expensive. Over the two and a half centuries that followed, clock ownership spread across the social classes; from being the sole prerogative of the wealthy, it had effectively become universal by the time of the First World War. An understanding of the growth of clock ownership in a stratified society is crucial to understanding clock cases in their social and historical context. In the preservation of clocks, status is one of the factors that affect decisions about conservation or restoration policy.

As clocks evolved from one technical innovation or social requirement to the next, new forms of clock case were adopted to accommodate the changes. Over the years, a number of factors have influenced the development of clock-case designs:

•  Mechanical improvements in time-keeping. One example is the introduction of the longcase clock, which was a direct consequence of the discovery of the pendulum and the innovation of the anchor recoil escapement. The case had to be designed to accommodate a pendulum of 1 metre in length while providing for the long vertical travel of the driving weights.

•  Domestic arrangements. As people became more conscious of time as the basis for organizing society, clocks and watches were made to present the hour almost continuously. From the earliest days, there was a requirement for both portable and fixed domestic clocks to supplement the public clocks that had been installed in towns across Europe since the late thirteenth century. Contemporary writings show an awareness of time beginning to enter domestic life. Up-and-coming middle-class public servant Samuel Pepys was one writer who made reference to it, in his diary entry of 31 December 1664: ‘As soon as ever the clock struck one, I kissed my wife in the kitchen by the fireside, wishing her a merry New Year, observing that I believe I was the first proper wisher of it this year…’. It seems that, as Pepys was rising up through the social classes, he was having to come to terms with concepts of time measurement and the division of the day. (Nowadays, he might have kissed his wife at one second past twelve instead of waiting until one o’clock!)

•  Fashion. Clock cases are rarely merely functional. With special exceptions, decorative elements incorporated into clock-case design and construction broadly followed contemporary fashions in furniture and decoration. Thus, the subdued and puritanical styles of the late seventeenth century gave way to sumptuous embellishment in the early eighteenth century. The exponential growth in clockmaking in the late nineteenth century gave rise to all sorts of design revivals and throwbacks.

•  Economy of construction. Following the rise of industrialization and the establishment of a waged society, clocks were made for all budgets. By far the greatest proportion were aimed at the lower end of the market, with high-volume manufacturers finding ever more economic ways of using materials and benefiting from standardization and economies of scale. Thousands of identical movements were fitted into thousands of identical cases and the cases themselves were often cleverly designed, with mass production and shipping in mind.

•  Diversity of choice in an expanding market. With consumers looking for something ‘different’ – a particular feature of the American market – hundreds of different designs were supplied, all housing somewhat similar movements. (In the nineteenth and twentieth centuries it was not a new phenomenon and, apparently, there were no two identical English longcase clocks made in the seventeenth or eighteenth centuries.)

The growth of time-consciousness in an increasingly organized society is mirrored by clock ownership. Mass production of cheaper clocks coincided with the beginning of the Railway Age, industrialization and consumerism.

Dated 1906 on the inscription, this English clock is made in the classical architectural style. The gilded, incised floral flourish is a typical late Victorian and Edwardian feature. The inscription gives a clue to the status of the first owner, a sergeant-major in the British Army.

The ogee clock (sometimes wrongly called ‘OG’) was made in great quantities by several American makers from the mid-1820s. The veneered ogee-shaped moulding on the front of the case allowed the door to be set back, making packing and stacking easier. The case is large enough to accommodate the vertical travel of the driving weights but transporting weight-driven clocks was problematic and they were discontinued in favour of spring-driven.

These pages in Brook Palmer’s 1967 Treasury of American Clocks (The Macmillan Company, New York) give an idea of just how many variations of just one basic design were available.

The movement and dial of this clock were made in London in about 1730; the case seems to have been made in the mid-twentieth century. The type of wood is completely inappropriate as is much of the design detail, but the clock has survived, albeit without its original case.

This book aims to show how a clock case can deteriorate with the passing of years, or generations or centuries, and how it can be preserved, either as an attractive domestic feature or, sometimes, as an important item of cultural heritage to be passed on to subsequent generations.

Clock cases are often damaged beyond repair or, worse, discarded in the mistaken belief that they are beyond repair. Consequently, it may be necessary to make a copy or replica of an old clock case. This book gives an example in which the design, materials and construction are based on an existing early clock case. Close attention to detail is critical – it often becomes apparent that even the minutest construction detail serves some hidden purpose. The clock-case restorer should always be on the look-out for the duality of form and function – subtle features that look like design peculiarities but which actually mask some construction detail.

It might seem unlikely that a pair of clock restorers would suggest making a replica case to house an old clock but there are some very convincing conservation arguments in favour of the correct replacement case. First, as long as the replacement case is not passed off as genuine, it serves to keep the sense of the clock, and, second, it is a really good way of preserving a clock that might otherwise be far more vulnerable to damage or complete loss.

Since we are craft-workers and restorers, we do not suggest new designs and the limit of our artistic endeavour is in occasionally designing appropriate replacement parts or even complete cases on the basis of detailed research.

THE PURPOSE OF A CLOCK CASE

A clock case fulfils two very different roles and clock-case design represents the union of the two functions:

1.   The practical: how to enclose the clock, protecting the movement from dust and intrusion while displaying the time.

2.  The aesthetic: how to project and reflect the owner’s status and tastes, or at least project an impression that the owner might like to create.

Dealing first with the practical, there are a number of key considerations when designing a case to fit a clock:

1.  The dimensions of the clock dial and the space into which it must display the time.

2.  The type of driving force of the movement – whether weight-driven or spring-driven.

3.  Whether or not it strikes or chimes bells, gongs or rods at hour, half-hour and quarter-hour.

4.  Whether it has a long or short pendulum, or some different type of non-pendulum escapement.

5.  The use or service conditions that the clock will encounter.

The fact that a clock dial is circular has been supposed to originate from the arrangement of a horizontal sundial. Likewise, the ‘clockwise’ direction of rotation of the hands is the same as the rotation of a shadow in the northern hemisphere. The word ‘dial’ is itself derived from a word meaning ‘day’ and the clock dial actually presents an ideogram of present time within the day. Until the recent introduction of the digital display, that circular form of dial with its astronomical inferences remained a standard in Western culture and has dominated the appearance of clock cases.

A carriage clock sold by Edwards & Jones, 161 Regent Street London W., a luxury goods shop located in a prestigious shopping street. The clock is designed to be transportable. With a platform lever escapement, it is compact and works in any orientation; for added protection it was supplied with a carrying case.

Ostensibly, it might seem that the purpose of a clock case is simply to support and protect the movement while presenting the dial so that it can be read conveniently. That is not the whole story; less obviously, most clocks are made specifically to convey an impression, usually of opulence (wealth, richness or lavish luxury) and taste. Certain accurate clocks such as regulators and astronomical clocks are mostly devoid of frivolous embellishment but nevertheless convey the impression of serious and austere purpose, often using finely finished exotic woods. Over the centuries, the practical or functional role of clock cases has been largely masked by design and embellishment.

Anything that requires making – clothes, furniture, ceramics, silverware, clocks – is influenced by designers and fashion leaders and, indeed, this has been the case for many generations. A modern example can be found in car bodies, which, if they were only functional, would all look roughly the same. Instead, their look differs according to make, status and date; as a result, cars of similar status and date tend to look similar. Car-body styling changes from year to year because manufacturers re-invest a significant proportion of the purchase price on design. For the potential car buyer, this year’s model is, for some reason, more attractive than last year’s.

Clock or ornament? In the second half of the nineteenth century, neo-classical and baroque styles appealed to the rising middle classes. This cast-brass clock, which houses a movement from the S Marti et Cie factory in Paris, was made some time after 1860 but before 1889. The styling should be seen through the eyes of a middle-class Parisian at the time of the Franco-Prussian War.

An Art Deco shelf clock from the 1920s or 1930s. The period saw new shapes and combinations of materials, Arabic numerals and, after 1930, chromium bezels. Even the hands are styled in the ‘Empire State Building’ shape that was so popular at the time. The width of the case is demanded by the use of long horizontally mounted brass gong rods.

Most clock cases blend the functional requirements of encasing a clock with a carefully chosen appearance that reflects the owner’s taste (or, arguably, lack of it). The huge variety in shape and style of nineteenth- and early twentieth-century clocks is something that can easily be taken for granted. It seems fairly clear that, from the earliest history of clocks, cases were carefully designed to create a certain impression. Clock ownership spread into the lower social classes in the eighteenth and nineteenth centuries. The wealthy classes bought furniture, clocks and other items that only they could afford. Those with a more limited budget bought items that aimed to mimic the opulence of the wealthy, but at a much lower price. It was only in the twentieth century that the new Art Deco movement largely standardized the design and construction of clocks.

ABOUT CONSERVATION AND RESTORATION

The two terms ‘conservation’ and ‘restoration’ cause much confusion, partly through misunderstanding and misinterpretation and partly through the sort of ideological separation that they imply. The two terms are not necessarily mutually exclusive and in languages other than English they do not necessarily exist side by side.

The point about preserving cultural heritage objects (including clocks and clock cases) is so that future generations will be able to inherit not only the physical objects but also all the knowledge that exists about them – how, why, and for whom they were made – as well as an understanding of the skills involved in their construction.

Conservation

Conservation is the more precisely definable term of the two: quite simply, it is the controlled and careful preservation of what remains of an object, for the enjoyment, enlightenment and/ or edification of future generations. However, although the meaning of conservation is less nuanced than restoration, for any conservation project there will still be a range of possible approaches, each with its own outcome. Conservators and stakeholders must weigh up the pros and cons to arrive at the action plan that represents least risk to the object.

Conservation work is slow and meticulous but commercial restoration can only be as time-consuming as the budget will allow. This is the lenticle window of a fire-damaged Dutch longcase clock (see later), acquired by a client who was willing to sponsor a protracted programme of restoration work. The little window in the trunk door gives a view of the swinging pendulum bob. The door alone took a full week to restore.

In the past, the term ‘conservation’ was usually taken to refer to complicated procedures carried out by specialist scientific experts in rather remote laboratories. With an increasing emphasis on the rarefaction and extinction of certain types of clock, it is increasingly for the amateur horologist to recognize and protect the endangered species of the clock world and endeavour to apply the formal rules of conservation in the sense of preservation.

Restoration – Definitions

Restoration as a term is often poorly defined and open to various interpretations. It has in the past been assumed to be synonymous with the term ‘renovation’ (making new) and a great many restorers still mistakenly strive for an ‘as-new’ look in clocks and antique furniture.

The idea that restoration returns the condition of an object to some undefined point in its past is difficult to apply. As an alternative, restorers often aim to stabilize the object with minimal intervention but with the intention of continuing use. In this case, the refreshing of surface finishes and other cosmetic work is done in a way that will not make irrevocable changes.

The restoration of clock cases is an activity open to those of all abilities, from professional restorers and serious DIY enthusiasts to more casual amateur hobbyists. It is a widespread commercial service within the wider antiques sector. The term ‘restoration’ should not be taken to imply less emphasis on research, record-keeping and documentation than is evident in conservation. Rather than prioritizing present use over long-term preservation, good restoration should preserve an object in a condition in which it can fulfil its original purpose. It is a difficult goal to achieve in practice.

It follows that imprudent restoration may seriously affect the future value of a cultural heritage object. Restoration work must be well thought out if it is to preserve the integrity of an object and give the best possible assurance of future value.

Restoration – A More Formal Approach

Towards the end of the twentieth century ideas about the nature and practice of conservation began to spread from the museums. Various organizations formulated policies about the preservation of cultural heritage and the workers – those people who mended, preserved, repaired or restored artefacts – seem to have polarized into two camps. The restorers (usually commercial service providers linked to the antique trade) often saw conservators as impractical purists with no idea of business. On the other hand, the conservators thought of restorers as unprincipled opportunists willing to despoil cultural heritage for monetary gain. The restorers justifiably felt that they were getting on with the work of returning broken-down old things to a serviceable condition for their customers; the conservators were seen as a theoretical scientific bunch associated with museums and learned dissertations.

Outside of the museum sector, trade groups began to appear: The British Antique Furniture Restorers’ Association was one trade organization that was formed when it was felt necessary to protect the trade, the consumers and the established craftsmen from the spread of untrained and unskilled ‘restorers’.

There is a strong argument that, without the efforts of untrained restorers, no matter how dubious their results by modern ethical standards, there would be a much less rich variety of cultural heritage objects to enjoy today. However, with the benefit of debate and clearer ideas, ethical restoration is becoming the norm for most professional restorers and there is no reason why the amateur cannot follow the same basic principles. Good restoration means achieving the best possible compromise between limited budget, continuing use and longer-term preservation.

The principles of good restoration are in essence the same as for good conservation and at a most basic level can be summarized as follows:

•  Identification and recording.

•  Informing and enlightening the client or owner and discussing the issues with them.

•  Making a rescue or action plan that involves minimal intervention while ensuring stability or at least preservation in the foreseeable future.

•  Recording the work as it is done.

CLOCK CONSERVATION – A SPECIAL CASE?

The subject of clock cases and their restoration has been somewhat overlooked in the past, for reasons that are related to the historical perceptions of clocks and time-consciousness in society. Of the clock-related books written over the last hundred or so years, there are a few that focus on the antique or heritage value of fine clocks, but many more are aimed at the repairer or mender seeking guidance about how to keep a functional part of an owner’s domestic arrangements in regular working order. On the one hand there is, for example, the great classic, English Domestic Clocks, written in 1913 by Herbert Cescinsky and Malcolm Robert Webster – a serious and comprehensive analysis of the evolution in styles of domestic clocks, including their cases. On the other hand there are many books about making and repairing that are more metallurgical or technical than philosophical. In the same year (1913) as Cescinsky and Webster’s great work, F. Garrard wrote Clock Repairing and Making, which was reprinted many times and is now available in electronic format. Garrard sums up in many ways the pragmatic, non-conservation thinking of its time. In one chapter, headed ‘Altering Clocks’, he describes how an original verge escapement of the kind found in very early clocks could be replaced with a modern anchor escapement. In Garrard’s time the emphasis was on timekeeping, but nowadays such an alteration would be unthinkable on conservation grounds. A new way of thinking starts to become evident in only slightly later books. In 1928, G. F. C. Gordon, in Clockmaking Past and Present, introduced the term ‘Conservation’, and expressed a more enlightened view:

The writer is of the opinion that gutting old lantern clocks and fitting eight-day movements will cease before long. In ever increasing numbers, people are realising that the genuine old clock with its original movement is far more valuable… The tendency today is for the public to become more educated.

Historically, clock-menders tended to adopt a pragmatic approach to keeping watches and clocks in working order for their customers and it is only more recently that the traditional work practices have come to be seen as contrary to the principles of conservation.

Are there any professional conservation guidelines for clock cases? The British Horological Institute advises its members in Conservation of Clocks and Watches (1995) that, ‘The restoration of clock cases is beyond the scope of these guidelines as it is a specialised field in which clock restorers should not, without previous training or experience become involved.’ The British Antique Restorers’ Association has a similar view: ‘We do not have any specific published guidelines and in practice we would advise that nobody attempt this work themselves and that it should be put in the hands of a professional restorer.’

Admittedly, clocks represent something of a special case when deciding how to apply rules about conservation or restoration because of some apparent contradictions:

•  Truly conserving a clock implies not allowing it to run, as this wears its internal parts. However, the integrity of an early clock is lost when it is no longer allowed to tick.

•  The requirement to keep a clock ticking involves periodic replacement of parts – is that level of intervention acceptable as a matter of good conservation practice?

•  It might seem incongruous to take great care in preserving a clock case when the movement has been repeatedly repaired.

The snags in clock conservation have undoubtedly spilled into the conservation of clock cases and there are no standards for clock-case restoration that are equivalent to those formalized and practised by members of the British Antique Furniture Restorers’ Association; one exception is the Irish Horological Craft Forum, which has recently published some conservation guidelines specifically to advise restorers working on clock cases.

CONSERVATION FOR THE FUTURE OR RESTORATION FOR NOW?

Who decides whether a clock should be conserved for the future or restored for the present? Ordinary clocks have owners; special clocks have guardians (museums, trusts or other bodies). The factors that influence whether or not preservation is appropriate – or, rather, whether the cost of conservation is justifiable – are usually taken to be related to the object’s importance to mankind. That may mean age, rarity, craftsmanship, artistry innovation or some special feature. It rarely applies where there are large numbers of the object in existence.

The real difference lies in the objectives of the owners or guardians of artefacts. There are three categories of owner/guardian who may avail themselves of third-party conservation/ restoration services:

•  Museums and similar guardians. Entrusted with keeping samples of heritage objects safe for the benefit of future generations, such owners tend to specify a no-compromise application of the principles of best conservation practice in any work on objects in their care. There is no such thing as restoration to museum standards; museums preserve what is there but they do not make up what is not.

•  Enlightened owners. Connoisseurs who understand the historical and social context of the pieces in their collections tend to prefer sensitive preservation methods that will not compromise the heritage or financial value. For the private collector of antique furniture or clocks there is an obvious conflict between the requirements of preservation and continued usage but, unlike museums, connoisseurs are unlikely to specify environmental conditions (humidity, light, and so on) for long-term preservation.

•  Unenlightened owners. Some owners have acquired antique objects purely as items of domestic decoration, with little real understanding of whether they are genuine original examples, cleverly re-worked pieces or simply out and out frauds. To a very large extent the unenlightened owner relies on the honesty and integrity of an antique dealer and there have been many examples where a trusting but inexpert buyer has been the victim of an unscrupulous seller. It is the role of the conservator or restorer to enlighten the client, but quite often the expert’s opinion is sought too late.

The case of Adolph Shrager and Basil Dighton in 1923 left a lasting blot on the reputation of antique dealers as a whole and sums up many of the pitfalls and distasteful aspects of the wider antique trade.

In 1922, Adolph Shrager, an alleged First World War profiteer, went to a London dealer Basil Dighton for advice about buying antique furniture. He bought about five hundred pieces but soon after discovered that many were overpriced fakes. Shrager sued Basil Dighton in a trial, in early 1923, that was widely reported. He lost both the first trial and the appeal, despite demonstrating that he was in the right. The case exposed establishment prejudice against Shrager, the nouveau riche Jew and alleged war profiteer. It also highlighted an apparently widespread practice of cheating vulnerable buyers with large quantities of fake furniture. It is often said in the antiques trade that if you want to find fakes, look in the collections of millionaires.

In more recent times, the internet has brought information about furniture and clocks to anyone interested enough to seek it out, but unfortunately there has always been a lucrative business in making attractive fakes or spoiling fine antiques for the exploitation of the gullible and unenlightened buyer. With his fixed ideas and inappropriate notions about restoration, the unenlightened owner is often very difficult to work for; much tact and diplomacy are required, especially when he has bought a fake or fraudulent reproduction and is inclined to defend his judgement.

Herbert Cescinsky was the expert witness retained by Adolph Shrager to prove to the court that the antiques he had bought were over-priced fakes. The court case, including the judgment against Shrager, has troubled the antiques trade and the legal profession ever since.

THE AMATEUR RESTORER / CONSERVATOR

Planning – A Staged Approach

There has been a recent growth in DIY clock restoration, with ordinary hobbyists attempting to take over what was once left to the high-street clock-mender. Case restoration has naturally been dragged along in the same direction. It is strongly recommended that an approach to restoration that is as close as possible to that of professional conservation/restoration should be adopted, for a number of reasons:

1.  It is the procedure that is mostly likely to maintain or improve the asset value of the clock.

2.  Doing it right usually gives more personal satisfaction and leads to a better understanding of how the original was made, enhancing the heritage value.

3.  Mechanical clocks and their cases are disappearing quite quickly and the preserved original examples will inevitably increase in value.

Having accepted these reasons for choosing sympathetic conservation over unplanned pragmatic repair, the DIY enthusiast should understand the basic principles of conservation, do some historical research on the project, make a detailed examination of the faults, noting the materials that are used, and then draw up a list of stages in a work programme.

There are several stages in a clock-case conservation project:

1.  Identification and historical research about date of construction, region and maker, status, provenance, rarity and any special features are all documented for consideration when the conservation work is at a planning stage.

2.  Detailed inspection and any tests that are needed to identify materials. As part of a service for his clients, the professional restorer prepares a formal document, the ‘Condition Report’, from the information obtained from identification and inspection. Good amateur restoration includes a similar descriptive document, with pictures and sketches, which should be kept with the clock because it adds to the asset value.

3.  An amateur is well advised to draw up a restoration plan, setting out the proposed measures to stabilize the object. Restoration plans, especially for clocks and their cases, tend to include the introduction of new parts that will replace lost, worn or irreparably damaged parts. There will be choices to be made about the level of intervention and replacement and alternative actions may imply different long-term outcomes. Work plans also invariably imply financial and time budgets; consequently, there will be compromises to be made.

4.  All work should always be recorded during restoration or conservation. Things do not always go according to plan and, whatever the conservator records, whether amateur or professional, will be an asset that goes with the clock for the benefit of future owners and conservators.

FINANCIAL GAIN

Financial gain has always been a strong motivator for the restoration of antiques and there is plenty of scope for providing expert services in an honest way, either as an amateur or a professional. As a career, restoration and conservation offer an opportunity to develop professional craft skills, building experience slowly while following a professional development plan until a consultant level is reached. In restoration and conservation, there is no end to learning.

Likewise, the amateur restorer/conservator learns from each project and develops the same techniques and manual skills as the professional. All restorers or conservators, whether amateur or professional, will be aware of the potential for increasing the asset value of antiques, including clocks.

It should not be a matter of concern to the amateur that his first attempts are clumsy or crude, but the subject of those first attempts might be chosen with some prudence. A great many fine clocks and pieces of furniture have been irreparably damaged at the hands of inexperienced restorers.

STYLES AND FASHIONS IN ENGLISH CLOCK CASES

After 1660, clock styling was modified in order to accommodate the newly invented pendulum. Earlier all-brass wall-hanging balance-wheel lantern clocks began to disappear in favour of the more accurate one-second pendulum long-case clock.

Although the overall layout of the English longcase clock persisted for about two hundred years, there was a progression in the detail. Early examples, which were made in the second half of the seventeenth century, usually in London, were slender and elegant, with a square dial that was rarely bigger than 10 inches (25cm) across. Oak was the preferred wood for constructing cases but they were frequently veneered, often in finely figured woods, particularly walnut. Some were ebonized (coloured black) or even veneered with true ebony or other exotics. Inlays and simple patterns of fans and stars are typical of the period.

As the art of the maker of clock cases developed, and tastes moved on from the austere puritanical post-Commonwealth period, burr walnut and marquetry panels appeared. By the end of the first decade of the eighteenth century, marquetry had reached its peak of perfection.

Known in Europe in Tudor times, lacquer began to appear in clock cases in England in the late 1600s, when all things from the East were fashionable, including of course imported Chinese porcelain ware (still known as ‘china’). On the best examples the lacquer was applied in China or Japan, but an inferior finish was sometimes applied in England. There is much confusion in the terms and the application of lacquer in England was referred to as ‘Japanning’, to differentiate it from the genuine article.

Mahogany was introduced into English furniture in the mid-1720s but, for some unknown reason, it was not adopted for clock cases until about 1740. That fifteen-year gap also saw the near-collapse of London longcase production with a complementary expansion in the production of more portable bracket clocks.

By the middle of the eighteenth century, production of longcase and bracket clocks had moved to the provinces. Longcases developed the neo-classical look to reflect the furniture styles of Thomas Chippendale and others, and regional styles became more pronounced. By the close of the eighteenth century, when painted iron dials took over from brass, the regions had fully developed individual styles.

The trend continued with the production of shelf or bracket clocks and occasional wall-hanging clocks carrying on in parallel with longcases, until, in the 1840s, mass production started in earnest in several locations of the New England region of the USA. American clocks began to be imported into Europe, with far-reaching consequences for the European clock trade. Hand-made clock production all but ceased, with makers unable to compete with the economy of scale and efficient manufacturing methods that the American producers had innovated. The American pieces represented a leap forward in terms of style, which made the more traditionally designed European clocks look somewhat old-fashioned. They flooded on to the European market at exactly the beginning of the modern industrial age and were soon absorbed into the homes of the new waged (and time-conscious) classes.

During the second half of the nineteenth century, the European clock trade began to mass-produce middle- and lower-status clocks in an attempt to compete with American producers. Apart from various woods the very wide range of case styles included stone, slate, marble, cast iron, brass and even spelter (an alloy of zinc, which is easy to cast).

WHAT IS MEANT BY HOROLOGICAL HERITAGE?

The concept of ‘horological heritage’ attempts to determine how and why clocks and their cases come to be classed as ‘worthy of preservation’, or not, and how perceptions change, and will continue to change.

Which clocks and watches are worthy of preserving for the benefit of future generations and which are not worth bothering with? It is ostensibly a simple question but the answer is somewhat complicated by the passing of time. Perhaps the real question to ask is, ‘which clocks are worthy of preserving now and which clocks will be worthy of preserving in the future?’ Inevitably, all mechanical clocks will at some time in the future be worthy of preservation; even early mass-production methods have already become outmoded according to current standards. A perfectly functional and widely distributed artefact such as a clock or a telephone becomes outmoded by technical advances or innovation, and within a short space of time is supplanted by the improved variant. Thus the balance-wheel clocks of the period before 1660 all but vanished with the introduction of the pendulum clock in the same way that mobile phones with alphanumeric keys all but disappeared with the introduction of the touch-screen smartphone.

The dial of a simple weight-driven Black Forest alarm clock. The alarm clock became necessary as society became more organized, and more aware of and governed by time. The exposed hands and alarm setting ring are easily accessible on the glass dial.

An English alarm clock made by Fattorini & Sons, Bradford, Yorkshire, in the second half of the nineteenth century. The case is made up in oak in the Gothic Revival style that was fashionable then. The movement is a very close copy of contemporary American spring-driven clocks but, in this variant, the hourly strike part is adapted to drive the alarm. There was a very strong demand for alarm clocks in the industrial heartland of England in the late 1800s.

A Black Forest alarm clock made in the late nineteenth century, probably by Philipp Haas & Söhne. German makers competed with the flood of American imports even to the extent of exporting to America. The case, including the reverse painted glass panel, is made in a rather German interpretation of an American style.

Added to the phenomenon of an object achieving rarity through being discarded as obsolete, a second factor compounds the rarity of earlier clocks. It is related to population and the distribution of wealth in society. In the year 1400 the population of the UK was about 3 million, with most of the wealth concentrated in a very small elite ruling class; it rose to 5 million by 1600, 11 million by 1800 and 41 million by 1900. From the 1600s, wealth began to be more widely distributed, with a new class of merchants and middle classes improving their lot through international trade, the provision of services and generally from the more complex organization of society. The nineteenth century saw the rapid expansion of the waged classes, for whom getting to work on time was part of the new order. Previously, the rural labourer’s day had been governed by the rising and setting of the sun, but the working day of millions of new factory, mill, mine, shop and office workers of the nineteenth century was governed by precise times. Huge numbers of clocks were made in the nineteenth and twentieth centuries and bought by these new and typically lower-income social strata. Alarm clocks were sold in their millions as time-awareness became a fact of life for almost all sectors of society in the developed world.

As a result of those changes in population and in the social order, a relatively large proportion of clocks were made in the nineteenth and early twentieth centuries. Clocks made in the Art Deco style of the 1920s and 1930s are almost always in the low-budget category. In other words, the establishment already owned clocks; it was the ordinary wage-earners who were new mass consumers.

With a switch from pendulum to balance wheel escapements, alarm clocks became far more portable. The Western Clock Company manufactured millions of alarm clocks in plain pressed-steel cases. The model shown here is the original Baby Ben, current from 1915 to 1927. It is shown on the relevant page of A Treasury of American Clocks, Brookes Palmer, 1967.

Chapter 2

Woods and Woodworking in Clock Cases

In describing some of the woods encountered in old clock cases, the cases are occasionally grouped together with antique furniture. Clocks are after all a part of the greater group of all antique furniture and the use of certain woods tends to be associated with particular periods in the development of styles and tastes in both furniture and clocks.

There are thousands of different tree species, and many types of wood have been used to make clock cases. Unfortunately space does not allow for a comprehensive review of all known species of wood, so only the more common ones are described here. They fall into several categories: European and North American coniferous softwoods (including the firs and pines); the European broad-leaf or hardwood species (almost always deciduous); and the Exotics (that is to say, timbers imported from the New World and the Far East). Each of these categories could be further sub-divided into construction woods and the woods used to make decorative veneers.

Furniture and clocks tend to harmonize. These high-status Queen Anne period (c.1710) pieces in European walnut pre-date the introduction of mahogany. The thick, hand-cut veneers are a feature of the genuine article.

The terms ‘softwood’ and ‘hardwood’ are confusing and often used inaccurately. Softwood is most often taken to refer to conifers – botanists call them Gymnosperms – usually straight-grained, resinous, cone-bearing members of the pine and fir families. All the other woods that are not conifers are the Angiosperms, a scientific term for any flowering plant – all trees that are not conifers produce flowers and seeds.

SOFTWOODS OR DEALS

A pine is a conifer that has its needles arranged in groups of two or more while a fir has single needles. Deal is an old-fashioned word derived from an early German word meaning ‘plank’. The terms ‘softwood’ and ‘deal’ are synonymous and softwoods are either red deal or white deal. Red deal is the term reserved for the better-quality softwoods, regardless of whether they are pine or fir (Scots pine, Douglas fir, hemlocks and larch are all classified as red deals).

The white deals are generally softer, inferior timbers, which are likely to be supplied by builders’ merchants as general construction timbers. They tend to be the cultivated species, the spruces, lodge-pole pine, Monterey pine and so on.

Softwoods have always been relatively easy to obtain. Historically, vast areas of ancient forest existed across Europe, although much of it was native European hardwood – oak, beech elm, ash and so on. The conifers were more dominant at higher altitudes and in the more northern latitudes.

The huge differences in quality between modern timbers and those found in early furniture and clocks are mostly related to the way in which timber production has been managed. Well into the twentieth century, virgin forests of slow-growing trees were brutally exploited, with no proper action taken to replant. In the nineteenth century, the supply of Baltic yellow pine from Scandinavia had begun to dwindle and a complementary trade was established across North America to feed world demand. Vast areas of high-grade timber were felled and imported into the industrial countries of Europe and at the same time European forests continued to dwindle. It was only after the First World War, when forest cover in the UK had dropped to 5 per cent of total land area, that people began to think seriously about future production and reforestation.

As commercial production and consumerism expanded with the Industrial Revolution, the ancient forests of Europe and North America were opened up to satisfy the demand for construction and other timbers. Makers of clock cases took advantage of the plentiful supply of good-quality timber to make a wide variety of complete cases, as well as parts that were not seen.

New white deal – an unnamed coniferous softwood from commercial sustainable forestry. The widely spaced growth rings indicate rapid annual growth. It is difficult to work – weak and quite unstable, with a high rate of expansion and contraction in changing humidity.

Old pine used to be known as Baltic yellow pine. The very slow growth shows in the closely spaced annual growth rings. Typically, wood like this is very straight-grained and almost devoid of knots and irregularities. The best was used in the manufacture of pianos, from which it is salvageable.

In North America, where clocks were being made by the million from the mid-1800s, cases were predominantly made in pine with very thin veneers.

In certain parts of Europe, Switzerland, south-east France, southern Germany and Austria especially, locally produced pine was used to make clock cases. Cuckoo clocks from the German/Austrian/Swiss border area are well known but other types of clock were also constructed from native straight-grained pine.

Pine (or more accurately, coniferous softwood) was used in the construction of country longcase clocks and, in order to mask the cheapness of the wood, the makers became expert in painted, simulated wood grain. Sadly, many of those old cases were stripped of their painted finish to create the stripped-pine look that became fashionable in the second half of the twentieth century. Pine clock cases that retain their original painted finish are now quite rare.

The American ogee clock probably dates from the 1850s. It is 99 per cent deal with very thin exotic veneers glued on the exterior surfaces to give a sumptuous appearance. The sides and back are plain pine boards.

An early nineteenth-century Austrian shelf clock case in the architectural style. The clock it houses was made by M Miller und Sohn, Wien (Vienna). The case is made entirely of heavy pine (presumably for stability), with the outer surface blackened (ebonized), possibly with black ink. The black and gold scheme is reminiscent of the Napoleonic French First Empire but remained popular for a couple of decades.

Back view of the same Austrian shelf clock. The massive pine components are glued together to form the box structure. The weight of the case is not a disadvantage but the style was copied several decades later in American and European slate clocks.

An early nineteenth-century painted pine longcase clock in the provincial style. It was made in the small market town of Ballymena, in Northern Ireland, for a clock by a local maker, Robert Russell, c.1810. The turned elements and other embellishments bear no relationship to the formal neo-classical designs of earlier longcase clocks but this one is nevertheless the evolutionary progeny of clocks that developed in London one hundred years before.

For clock-case restoration where the quantities of replacement wood are quite small but the range is very large, there are a number of potential sources. Architectural salvage yards often hold stocks of useable panelling and floorboards. Scrap furniture is another likely source, with drawer lining and carcass furniture (for example, chests) all offering possibilities, but the workability of the softwoods is seriously impaired by paint. Any softwood that has been painted is something between difficult and impossible to work. (An old-fashioned carpenter might say that painted pine has lost its ‘nature’.) Although it is only available in small quantities, the very best-quality straight-grained pine is to be found in the timber frames of old pianos.

In the rush to obtain old pine or anything else from antique furniture, the worth or heritage value of that furniture should be considered.

EUROPEAN HARDWOODS

Broadleaf trees are usually called ‘hardwoods’ but they are not necessarily hard woods. There are also plenty of soft broadleaf woods, which have been used in a wide range of applications including furniture and clock cases. Hundreds of members of the birch and willow families are recorded and many of them have been used in making furniture and clock cases. Lime (linden in North America) is another good example of a soft broadleaf; it is used extensively for carved elements in clock cases because of its almost featureless but soft texture.

According to the English writer and antiques expert Percy McQuoid (the defendant’s witness in Shrager v Deighton), there were four ages in classic antique British furniture between the Stuart kings and the close of the eighteenth century:

1.  The Age of Oak, 1500–1660.

2.  The Age of Walnut, 1660–1725.

3.  The Age of Mahogany, 1725–recent.

4.  The Age of Satinwood, 1775–1810 and later.

Lime wood used for student practice pieces. Restoration students have to practise carving techniques and lime is the perfect wood for carving. Every wood has a useable characteristic and it happens that lime is very soft but cuts cleanly.

From the earliest days of world trade and colonial expansion, timber was imported into Europe in increasing quantities as various regions of the world became more accessible. Sadly, there are a great many examples of timbers that were ‘discovered’ during the age of expanding world trade and empire-building, over-exploited in the nineteenth and twentieth centuries and are now considered to be in danger of extinction, along with the plant and animal species that rely on them.

Obviously, the use of endangered timber species creates ethical conflicts for the restorers of clock cases, as it can involve a contribution to a loss of natural heritage in the interests of cultural heritage. It can be difficult to source appropriate timbers, but many pieces of old furniture and other pre-used timbers are scrapped annually, and that wood, which would otherwise go to waste, is more than likely to yield all sorts of suitable material for making replacement parts or complete cases.

The more commonly used European woods include: oak (several species), beech (and the related sweet chestnut), ash, sycamore (and the related maple), elm, alder, birch, willow (and poplar), lime (also known as linden), horse chestnut, Circassian or English walnut, apple, pear, cherry and other fruitwoods.

Scrap and salvaged wood stacked in the workshop. Storage is always a problem but mahogany tables, walnut pianos and all sorts of veneered furniture are scrapped regularly.

Oak

Oak is widely distributed in the temperate latitudes. There are dozens of natural members of the oak family and, in addition, dozens of cultivated hybrids. To further complicate things, pollard oak, which is occasionally found in clock cases, has a different appearance, being naturally darker in colour and with a highly disturbed grain. Pollard oak is formed when an oak tree is coppiced (or pollarded). A burr gradually develops with repeated pollarding and, when a bracket fungus develops on the cut surfaces, it absorbs into and darkens the underlying wood. Veneers of pollard oak are found in early clock cases and it subsequently enjoyed repeated bouts of being in fashion, including the Art Nouveau period.

In terms of commercial production, the major species are English oak (Quercus robur) and American white oak (Quercus alba). The two species vary in appearance and workability; the American variety tends to be straighter-grained because it is from tall straight trees and hence it is easier to work. Oak, or any wood containing tannic acid, can be stained using modern chemical wood dyes. Traditionally, the method for staining or artificially ageing oak is the oxidizing agent potassium permanganate in a dilute aqueous solution of 50 grams in 2 litres of water.

The characteristic dark colour and strong figure of pollarded oak made it popular for decorative applications. When oak is cut exactly on the radius of the stem a characteristic figure of the medullary rays is revealed.

Sawn timber replaced riven or split oak in the eighteenth century and the surfaces showing the wainscot or quarter-sawn figure became more scarce, replaced by through-and-through cut boards.

A section of contorted oak showing the relationship of the growth rings and the medullary rays. At lower right and along the top edge, fissures or heart shakes have developed on the medullary rays.

Oak was used from the earliest times as the construction timber for the better qualities of large (longcase clock) cases, but it was often covered with veneers of either native or imported exotics. Lower-status provincial longcase clocks from the 1730s used oak in their construction, mostly without veneer.

The way of making useful panels from logs of oak changed over the seventeenth and eighteenth centuries from splitting down the stem to sawing. Consequently, old oak is likely to show variations in thickness, with a crudely flattened ‘rough’ side. Oak boards are stronger and more stable when cut as a radius of the log and the diagnostic feature of oak cut in that way is the radial medullary ray structure that is exposed on the surfaces. Splitting down the diameter of the stem will naturally create surfaces parallel to the medullary rays, which are never uniform, so the appearance is the characteristic random pattern for which the American term ‘quarter-sawn’ is now becoming standard. The boards in good-quality early eighteenth-century clocks, even those subsequently covered by veneers, are almost always wainscot but, by the end of the 1700s, timber was increasingly cut into parallel boards and the wainscot was reserved for the front panels.

Wainscot or quarter-sawn oak is often seen in the doors of longcase clocks. This one was made in the early eighteenth century; the cross-band is European walnut (often mistaken for mahogany).

Because oak is both strong and durable it was often used for parts such as the hood doors of longcase clocks where the design requires the frame components to be quite slender and narrow.

Although oak was replaced by walnut for chairs and furniture in the reign of Charles II, it remained the wood of choice for making clock cases. Indeed, oak continued to be used in English and continental clock cases after the introduction of mass-produced clocks in the mid-1800s. North American oak was imported into the Victorian and Edwardian English furniture trade in huge quantities and it was used extensively for clock cases up to the First World War period.

An English alarm clock made in the mid- to late nineteenth century. The movement is a direct copy of an American 8-day spring-driven clock. Oak is used throughout, suggesting that it was relatively inexpensive. The only piece of wood in this clock that is not oak is the European walnut carving above the dial.

For a brief period at the beginning of the twentieth century, American shelf clocks were made by pressing or embossing oak to give a characteristic impression of having been carved.

In terms of woodworking characteristics, oak is strong, tough and hard, so really sharp edge tools are required. It is not amenable to gluing and prior to the application of any glue, the surface should be moistened to raise the grain and allow the glue to bond to wood fibres.

It can be worked to a smooth flat surface, but with age the grain sometimes shrinks back to leave a slightly ridged surface.

Oak darkens with age and exposure to light; European oaks tend to become progressively darker with a grey hue, while American oaks take on a more attractive reddish honey colour. Although it will darken significantly with the application of a dilute solution of potassium permanganate, other natural dyes were used before the advent of chemical stains to give oak an attractive red tint. These included Alkanet, made from the root of the bugloss plant, and Dragon’s Blood, made from the root of a species of Dracaena tree.

The surface treatment of oak is a matter for personal preference, but, traditionally, it was rubbed with wax rather than polished to a high gloss with shellac. There are many exceptions to that rule and the pieces of furniture or clocks that look best with a bright shellac polish are formal rather than country and dark rather than light. As a result, it might be quite appropriate to apply a high shine on an old oak clock case. (In English furniture, prior to 1790, burnishing with wax was the norm. French polishing with shellac polish appeared only after that date, but its use did spread rapidly.)

The heartwood of oak is quite resistant to infestation by furniture beetle but the lightercoloured and more porous sapwood is not.

European Walnut

One of the more significant timber species in older, high-status clock cases is European or Circassian walnut (Juglans regia). The botanical name apparently means ‘Jove’s nut, fit for a king’. It is the woodworker’s king of woods but should not be confused with the dark grey North American variety (Juglans nigra), which, although it is often found in both European and American lower-status clock cases made after the mid-nineteenth century, is different in terms of its woodworking qualities.

The use of European walnut spread rapidly into English furniture and clocks at a critical time in their development. After the austere puritanical look of the William and Mary oak period (up to the end of the 1600s), there was a return at the beginning of the eighteenth century to the baroque fashions that had originated on the continent. Along with that shift in styling, woodworking also grew up from the constructions of the joiner-carpenter to those showing the sophisticated skills of the cabinet-maker. Exquisite veneers and inlays in the finely constructed clocks and furniture of the Queen Anne period (1702–1714) gave an air of opulence at a time of expanding economic activity.

Freshly sawn and planed European walnut. The fine pore structure and variegated striping are diagnostic features. The colour is not; this surface will age to anything between mid-brown and dark straw in a matter of years. Walnut was often artificially coloured with red dyes to make it look like the more fashionable mahogany.

European walnut can display many different appearances, from plain stem wood to highly contorted burrs. The stem wood, which often carries a dark stripe down the wavy grain, varies in colour between grey and reddish brown to a pale yellowish-cream colour; with age, it tends towards dark straw colour. It works, carves and polishes exceptionally well; indeed, working European walnut with surgically sharp tools is an extremely pleasurable experience enjoyed by only the lucky few.

Because of the range of appearances seen in walnut, it is often mistaken for mahogany, especially when it has been artificially coloured with Alkanet. In the late twentieth century, antiques auctioneers invented a nonsense name for a non-existent walnut species – ‘red walnut’ was used to describe red-stained walnut that aimed to mimic the appearance of mahogany. The term has also been used to describe the mahogany used to make fake furniture purported to be from the Queen Anne period, a time before the discovery of mahogany. (The name Juglans rubra had been used in early works on botany, applied to the nut of an American hickory tree.)

Be warned! There are examples of genuine pieces of furniture and clocks from the first half of the eighteenth century, made from red-stained walnut to imitate the highly fashionable but grossly expensive mahogany.

European walnut has been used in clock cases since the end of the seventeenth century, both as construction timber and also as its decorative burr and other strongly figured veneers. In the solid it carves particularly well and has been used up to present times, especially where carving is a significant feature of the clock. However, it is perhaps best known as the burr veneer that has enjoyed spells of fashion from the Queen Anne period to the Art Deco of the 1920s and 1930s.

As a veneer, it is not just the burr of walnut that is used as a decoration. The stem wood also often shows attractive features, such as alternating dark stripes, and occasionally a ripple or moiré figure in which light and dark areas seem to shift as the viewpoint is moved, giving the surface of the veneer an impression of depth. Part of the cabinet-maker’s skill was in selecting and cutting the wood so that certain features could be shown off to enhance the overall effect of the work.

Cuckoo clocks, which have remained popular since their first introduction in the early nineteenth century, are embellished with carved birds and plants. European walnut lends itself to this type of carving.

A piece of modern burr walnut veneer. It is thin (about 0.6mm) and unstable. The colours that might be expected in a piece of polished burr walnut are not present in the raw wood; they show only after an application of linseed followed by shellac.

Salvaged burr walnut veneers. These book-matched pairs have been sawn from a scrapped upright piano for use in the restoration of early clock cases. They are quite thin and, in order to keep them stable, they are cut from the ground wood with some thickness retained as a backing. This results in the salvaged veneer being of approximately the same thickness as an eighteenth-century hand-cut veneer.

In this view of the edge of the salvaged burr walnut veneer, the ground is visible as a pale line under the thickness of the walnut.

A flitch of walnut veneers with a strong-coloured figure. Some veneers are rotary-cut like pencil sharpenings, but these are straight-cut or ‘throughand-through’.

A moiré figure in walnut creates an impression of depth and movement. The wood was carefully selected by the case-maker to show off that feature in this early eighteenth-century Irish clock case.

In terms of its woodworking characteristics, European walnut is the best woodworker’s wood, with the possible exception of mahogany. It is strong and tough although not unduly hard. It cuts and carves well to give sharply defined edges. It also glues well, reacts well to a wide range of colouring agents and dyes, and it polishes well to display an infinite variety of figure. Walnut burr veneers were once cut quite thickly by hand, but, following the introduction of special machinery in the nineteenth century, burr veneers have been cut increasingly thinly. Thin veneers are difficult to lay because they tend to distort after cutting.

Beech, Sweet Chestnut, Ash, Yew and Sycamore

The light-coloured woods were less frequently used in clock cases and, although native hardwoods were always relatively easily available, pine was the wood of choice after oak and walnut. Beech and sweet chestnut are members of the Fagaceae family and various varieties of each are distributed across the temperate latitudes. Common or European beech is hard, with good workability, so it is used for framing but seldom as the outer surface of a clock case because it is a rather plain, almost featureless wood. Chestnut is often confused with ash because of the appearance of its strongly developed annual growth structures on cut surfaces. Both ash and sweet chestnut are suitable for country-style clock cases. Horse chestnut, which is unrelated to sweet chestnut, might also be encountered in country clock cases. It has no particularly attractive qualities for cabinet work and fine clock cases.

Several species of ash are distributed across the northern-hemisphere temperate zone in Japan, North America, Europe and Asia. The special strength and toughness of European ash (Fraximus excelsior) do not necessarily make it attractive for clock cases, but it is occasionally encountered serving as the structural part of a veneered case. The veneers of stressed limbs of ash and sycamore can show an attractive ripple.

Like many woods, beech (Fagus sylvatica) displays variations in appearance according to the light. Rotating the two pieces of beech shown here alters the appearance of the characteristic flecked figure, which is caused by the medullary rays.

Sweet chestnut (Castanea sativa) is a relatively soft wood with a strong figure, occasionally used in country clock cases.

Ash (Fraxinus excelsior) is similar in appearance to sweet chestnut because it grows in a similar environment and also needs a strong pore structure to transport large amounts of sap to rapidly growing leaves in the spring.

Sycamore (above) and maple (below) are both members of the Acer family. They are both quite hard, relatively featureless but stable woods. The cross-wise fiddle-back figure in sycamore is used in decorative veneers.

Yew is an attractive wood, with marked differences between the orange-brown heartwood and the light-coloured sapwood. All parts of the yew tree are poisonous and the dust should never be inhaled.

EXOTIC TIMBERS

Mahogany

There are several species of mahogany, as well as a number of timbers that are related (the true mahoganies) and some that are used as substitutes.

The genuine mahoganies are: Cuba mahogany (Swietenia mahagoni), which is native to the Caribbean islands and Florida, is heavy and dark, and works and takes a polish well; and Honduras mahogany (Swietenia macrophylla), or big-leaf mahogany, which grows from Mexico to the Amazon basin. Like Swietenia mahagoni, Honduras mahogany is an endangered species. It is noticeably less heavy than Cuba mahogany and tends to fade in sunlight.

There are several timbers called true mahoganies because they are botanically related to the above. African mahogany (Kaya senegalensis) is exported from West Africa as a mahogany substitute. Other substitutes, either used locally or exported, are Chinese, Indian, New Zealand and other Meliaceae species

The more common but botanically unrelated mahogany substitutes are: sapele (Entandrophragma cylindricum), a reddish-brown Central African wood with an interlocking grain structure, which can substitute well for mahogany; and utile, also called sipo mahogany (Entandrophragma utile), which is similar in appearance and properties to sapele.

From its first introduction into English furniture in the mid-1720s, Caribbean mahogany influenced both design and methods of construction. It appears in clock cases only in the 1740s, however. The most plausible explanation for this delay seems to be the coincidence with an almost complete cessation in longcase clockmaking in London by the 1730s. Very shortly after the introduction of the break-arch dial, the fashionable London makers turned their hand to making bracket clocks. Simultaneously, there was an expansion in the production of longcase clocks in the country towns and villages.

It seems that there may have been a conservative reluctance on the part of the country carpenters to adopt the new wood. A more likely explanation lies in the very heavy import tax of £8 per ton until 1747, which discouraged the use of mahogany in all but the most expensive furniture and clocks. Mahogany furniture from before 1747 was made only for the exceptionally wealthy.

An early nineteenth-century Irish clock showing the use of mahogany, both solid and veneer, to create a conservative, subdued impression of neo-classical taste.

The tax on mahogany also had the effect of promoting the selection of finely figured woods because the tax did not differentiate between ordinary stem wood and attractively figured woods. The use of mahogany veneers at that time was another side-effect of the tax.

From the 1750s, mahogany became the wood of choice for clock cases and its special properties were well suited to the neo-classical designs of Thomas Chippendale and others.

The sudden shock to the European clock trade in the 1840s, caused by the mass importation of American clocks, changed for ever the styles of English clocks and the quantities in which they were made. That shift coincided with the rise of the waged class in the new railway age. English clock cases of the mid-nineteenth to early twentieth centuries continued to use mahogany, both in the solid and as veneers.

Another Irish clock but from a different time and a different social order. The very thin, machine-cut mahogany veneer applied to this shelf clock of c.1890 makes inlay work easier.

The post-First World War period saw a renewed interest in clock production with styles suited to the day, often cheaply made and veneered with mahogany. The pronounced stripe of sapele replaced the more homogeneous appearance of Honduras mahogany and it became one of the typical woods of the Art Deco period.

In terms of their woodworking characteristics, the true mahoganies work well. They do often have a contrary or opposing grain, so extremely sharp tools are necessary, and certain cuts of mahogany are notoriously difficult to plane smooth. It turns and carves well, leaving sharply defined edges, and it polishes well to reveal attractive colours and strong figures. Mahogany was traditionally darkened by the application of a dilute solution of the oxidizing agent potassium dichromate.

Satinwood veneer is attractive because of the moiré figure. It began to appear in Europe in the 1770s and inlaid panels were often further embellished with painted detail.

Satinwood (West Indies and East Indies)

Satinwood was introduced to Europe from the Caribbean in the 1770s and became instantly fashionable. It is attractive because of the mottled grain pattern, which resembles ripples in a piece of satin fabric, hence its name. It is almost only seen in veneers, often in panels, and its presence indicates a dates after 1770. Much later, a similar wood of the same vernacular name was discovered in what is now Sri Lanka. To distinguish it from West Indies satinwood, the Ceylon (present-day Sri Lanka) variety is called East Indies satinwood.

Satinwood is extremely hard and abrasive to work and quickly blunts edge tools.

Rosewood, Kingwood, Tulipwood – The Dalbergia species

Although the Dalbergia family is quite widespread throughout the tropics, true rosewood is native to the South American mainland. It was discovered in Brazil in the early 1800s and enjoyed a short spell of popularity in the 1830s to 1840s. Supply dried up but further sources were discovered towards the end of the century, promoting the late-Victorian and Edwardian fashion for rosewood furniture.

Brazilian rosewood (Dalbergia nigra) is now an endangered species, so the only source for restoration materials is in scrap furniture.

Due to the high demand and limited supply of Brazilian rosewood, and its continued exploitation in recent decades, it has been listed in the most restrictive category of the Convention on International Trade in Endangered Species (CITES), Appendix I. Not only is the timber restricted from international transport, but also finished products made of new Brazilian rosewood may not legally cross national boundaries.

There are a number of Dalbergia species that may be used as a substitute for true rosewood, but, to fulfil the need for true rosewood veneers for restoration, salvaged material is the only practical and ethical option.

DISTORTION IN SAWN TIMBERS

Several types of distortion occur in sawn timber, mostly to do with the release of stresses or differential shrinkage after sawing:

•  Cupping is the tendency for boards to curl across the width. It usually happens as the freshly cut timber is dried but can occur when seasoned timber is cut through to give thin sheet. The cupping tends to straighten the growth rings.

•  Twist or wind happens when the board is cut from the edge of the stem. The board twists along its length.

•  Cupping and twisting tend to affect flat-sawn boards. Rift-sawn timber is more stable.

•  Bow is a bending up of the board along its length; it is caused either by poor stacking or the relief of stresses during sawing.

•  Crook is a sideways deformation; the board will lie flat but turns along its length. Crook is usually caused by an asymmetry in the core of the tree.

•  Shakes are natural fissures in the wood fibres, radially (heart shake) or coincident with the growth rings (ring shake). Shakes can be caused by poor seasoning and end shakes are a feature of air-dried boards that have been exposed to a localized drying effect from too much ventilation.

•  Shrinkage can occur with age across the grain in certain woods. The veneered, framed doors of early longcase clocks often show disruptions to the veneer where the ground wood has shrunk.

Distortions that commonly occur in softwoods appear during cutting and/or drying. Flat-sawn timber is most susceptible; rift-sawn is usually the most stable.

WORKPLACE AND TOOLS

With limited space available, this book cannot be a woodwork manual, but guidance is given on some of the techniques involved in working on clock cases. First, however, it is important to have a good workshop and sharp tools in order to achieve a good standard of workmanship.

The Workplace: Safety and Organization

Working in wood can be a pleasant occupation but, as with any activity, there are a few hazards to consider.

The risk of fire is always present where there are accumulations of inflammable material. Wood shavings, solvents and wire wool are all very inflammable. Minimize the risk by keeping the workplace clean and tidy. Know where the escape routes are. Understand the operation and limitations of fire extinguishers and position them near exits.

Keeping the workplace tidy is one of the good habits that cabinet apprentices used to learn. In the long run, it helps to avoid personal injury and inadvertent damage to other people’s antiques.

Fix or hold the work properly. The first requirement is a solid bench. The best benches have plenty of natural light and at least one vice big enough for any bench work. Safe and comfortable work on large clock cases is almost impossible without a permanent fixed bench.

Sharp Tools

Sharp tools are the safest to work with because they take less pressure. They allow for precision and finesse without brute force. Attempting to work with blunt tools is frustrating, dangerous and unprofessional.

While there is plenty of good advice and guidance about how to work wood both in printed material and on the internet, the topic of sharpening edge tools is less thoroughly covered. The best edge tools are probably the old ones that are still readily available. They tend to be stamped with words like ‘Made in Sheffield’ or ‘Made in Germany’.

Chisels, gouges, various types of planes, marking knife, drill bits and cabinet-maker’s scraper. All need to be ground and honed to razor-sharp edges. Blunt tools cause injuries.

Sharpening an Ordinary Wood Chisel

1.  Inspect the general state of the tool and the nature of the cutting edge. Try to estimate how much metal must be removed to make the edge straight, uniform and sharp. In extreme cases it may be necessary to use a grinding wheel. If so, apply only light pressure because if the edge is heated it will lose its hard temper. Never let the edge get hot enough to turn the steel a blue colour.

2.  On a medium to coarse oil stone, start by grinding the back of the chisel flat.

3.  Turn the chisel over and grind the bevel carefully with moderate pressure. With a skim of oil on the surface of the stone, the correct angle is when the oil just squishes out from under the edge. Grind away the coarse grinding marks from the wheel.

4.  Using a fine stone, repeat Steps 2 and 3. Start with the back and then rub the bevel, keeping it, as far as possible, flat to the stone. Most bevel-edge tools develop a slight curvature on the bevel.

5.  Remove the burr from the edge by polishing the back and bevel alternately on a hardwood block. Keep the bevel and the back flat to the block – lifting the back even slightly will offset the edge and render the chisel difficult or impossible to use.

6.  With the burr removed, the chisel should now be fit to use. Test on a piece of softwood.

Just enough metal should be removed on the grinding wheel to take away any chips on the edge.

Most stones that start flat develop depressions. Understand how the blade interacts with the stone.

When the angle is correct, oil will squish out from under the edge.

The coarse stone only prepares the edge for sharpening; the burr along the edge will be quite noticeable but the bevel should be uniform

The fine stone will leave a thin ragged burr.

Polish away the burr on a hardwood block. Do not be tempted to use softwood or, worse, a leather strap, which will make a small but annoying counter-bevel on the back of the edge.

When the edge is properly sharp, it should be invisible to the naked eye.

Maintain about 10 degrees of relief behind the bit by filing accurately and gently.

Sharpening Drill Bits

Good drill bits are hard to find so only remove the absolute minimum of metal. A fine diamond file is suitable for intricately shaped bits. Keep the relief behind the cutting edge so that the metal behind the edge does not rub on the wood in the bottom of the hole.

Sharpening a Gouge

1.  The gauge illustrated next is an out-cannel gouge, meaning that the bevel is on the outside of the curved blade. Rub the bevel over the oil stone in a figure-of-eight, rolling the blade from side to side (this takes practice).

2.  Use a slip stone to rub away the burr on the flat inside of the curve.

3.  Take a piece of softwood scrap about the width of the gouge and cut a convex and a concave form with the part-sharpened gouge.

4.  Smear a little chrome polish on to the softwood block and hone each side of the gouge, the bevel in the concave groove and the back (which is the inside) on the convex round section.

5.  For narrow gouges, fine emery paper glued to dowelling of the right diameter serves to hone the inside surface of the gouge.

6.  The final test. Find a piece of scrap wood and cut across the grain. A continuous shaving usually means that the edge is sharp and that the blade can push through the work easily.

The flatter the angle of the bevel, the greater the risk of damage to the edge, so grind the angle to suit the wood and the work. Aim for a flatter angle for fine work and soft woods such as lime, and a thicker angle for heavy work in hard woods.

Hold the gouge on the bench and move the slip stone. It is easier, more accurate and safer.

A small offcut is sufficient to hone or polish the edge of a small gouge. It is customary to polish all carving tools – it aids control as the blade slides over the work more easily.

A few rubs on each side will leave a mirror-like finish. The black discoloration on the wood block is fine steel that was abraded from the gouge by the polish.

A slip made from 600-grit abrasive paper glued on to a piece of 3/8in dowel will substitute for a slip stone to buff the inside of a small gouge.

If it does not cut cleanly, look at it carefully – any faults in the sharpening will be obvious.

Re-Cutting and Sharpening a Saw

Although disposable saws are cheap and plentiful, it is less easy to find the smaller sizes. The example here is a dovetail saw with a patch of corrosion that has caused the loss of a section of the blade. There is enough good metal left in the blade to file off the damage and re-cut the teeth.

In order to file off the old teeth neatly, the saw is clamped into a bench vice with two strips to support the blade.

Cut a piece of threaded bar of the desired pitch (about fourteen teeth per inch) down the axis and use the half-round as a guide to file new teeth into the flattened saw blade.

Try to use the same number of strokes of the file for each new tooth, keeping the angle constant.

Finally, set the teeth by pressing alternate teeth to the opposite sides of the blade.

It is impossible to do good work without making sure that tools are sharp enough and working with blunt tools will certainly deflate the satisfaction that clock-case restoration offers.

Good saws are hard to find and, even with this much damage, a decent one is still worth saving.

Set up the saw blade in a vice and use a rasp or flat file to remove the damaged area. Do not be tempted to use an electric grinder, which might spoil the temper of the steel by overheating.

The threaded rod is just to get the pitch of the new teeth even.

The triangular file will naturally follow the profile of the threaded rod and cut the new teeth correctly.

A saw set is used to squeeze alternate teeth off the flat surface of the blade, giving ‘set’, which will allow the saw to cut a slot that is wider than the blade.

Chapter 3

Some Special Techniques in Clock-Case Construction, Restoration and Conservation

There are a few techniques that apply to cabinet-making in general but are of special interest in the clock-case sector. These techniques – carving, veneers and inlays, gilding, painting, polishing and turning – tend to relate more to decoration or embellishment than to structure.

SOME COMMONLY USED TERMS

Carving

It probably goes without saying but carving in wood or stone can be a representation of lifelike forms or geometric designs, and it is often a combination of both. There are only a few standard ornaments in neo-classical styles. The acanthus leaf and the Vitruvian scroll, which occur in classical Mediterranean architecture, are common motifs. The cornice moulding around the hood of a neo-classical longcase clock case often blends into a carved swan-neck pediment.

The pediment of a late nineteenth-century Vienna-type clock; the acanthus leaves are set out on a matted ground with a typical scrolled outline.

Columns, Balusters and Pillars

Columns are vertical members that support something, while a baluster is simply a small column, such as might be used in architecture to support a hand rail. A pillar is a column that is not circular in section. In clock cases, whether a feature is a baluster or column depends on the architectural context. The support is almost always notional within the architectural theme of the case. The five column types or orders in classical architecture are Doric, Ionic, Corinthian, Tuscan and Composite. The detailed geometry of each is readily available online or in books such as Thomas Chippendale’s Gentleman and Cabinet-Maker’s Director, published c.1760.

The columns or balusters of the hood follow those in the trunk. The short trunk door and the third period painted dial date the clock to the 1830s; it has a style characteristic of the West Midlands area of England.

Cornice

A cornice is a moulding at the top of a vertical surface, usually projecting.

An extravagantly sized cornice on the hood of an early nineteenth-century Swedish longcase clock.

Finials

Finials are frivolous decorative terminations, often turned, that are used to soften the harshness of geometric edges. They may also be made up as modelled animals and mythological characters.

Orb and spike finials are quite widespread in longcase clocks from about the 1730s until the late 1700s. These are brass, but in country clocks gilded turned wood was very popular.

Finials are prone to loss and replacement and the eagle and ball finial here is actually a modern reproduction. The eagle and ball motif is very widespread.

Intaglio and Intarsia

Intaglio is a decoration or design incised or cut into a surface.

Intaglio is an ancient art form that was used in Ancient Egyptian architecture to show outlines of pharaohs, and other images. The fanciful intaglio design in this late nineteenth-century black calcareous slate clock case is characteristic of the pre-Art Nouveau period. Gold leaf is applied to the incisions.

Intarsia is a special form of marquetry in which complex pictures are formed using different woods, which may be coloured.

Marquetry

Marquetry involves making up decorative patterns or pictures using small pieces of wood veneer.

Marquetry is a plainer or more abstract form of intarsia, which creates pictures in different woods. Alternate sheets of rosewood and satinwood are temporarily glued together and the pattern is cut with a fine saw. For every marquetry composite there is usually a complementary or negative version (for example, satinwood in rosewood and rosewood in satinwood).

Moulding

An architectural term for a shaped decorative strip, such as in a cornice. Mouldings in clock cases tend to be both decorative and functional. In the decorative form they soften the impression created by large featureless areas. The moulding that joins the trunk to the base in a longcase clock also has a structural role.

Hand-cut mouldings for longcase clocks. Handmade clock cases utilize an infinite variety of profiles because every maker used his own non-standard tools.

Parquetry

A form of marquetry where inlays of different woods are arranged to form geometric patterns.

Pediment

Usually an approximately triangular top section in classical architecture; in clock cases and furniture the term is used to describe the top section. Styles of pediment have varied over the years, with a marked development during the French First Empire period, for example.

The triangular pediment surmounts the horizontal cornice moulding. Architectural pediments have enjoyed occasional brief spells of fashion. This clock was made in Ireland at the time of the Napoleonic Wars, a time of remarkable jumps and reversals in style. (For example, it was the only period in longcase clocks when Arabic numbers were used for the hours.) The style of pediment is reminiscent of early Austrian Vienna clock styles.

A simple twist is made up between the centres of a wood turning lathe, the blank being turned slowly by hand.

Turnery

The term ‘turnery’ encompasses anything turned in a lathe but usually refers to wood objects such as balusters and finials. Wood-turning became fashionable in the seventeenth century and simple twists were incorporated into the hoods of early longcase clocks until the neo-classical revival of the Queen Anne period (1702–1714). The symmetrical or mirror image nature of the construction is maintained by using both left- and right-handed threads.

Small turned ornaments applied to clock cases appealed to the Victorian taste for frivolous embellishment. They were usually cut into matching pairs and glued on to clock cases.

Turned and halved sections are glued on to this late nineteenth-century German clock to break up the flat areas, creating a fussy baroque appearance.

WOOD-CARVING IN CLOCK CASES

Carving is one of those skills that must be learned the hard way – by practising – and each new carving project will develop techniques and give increased confidence.

There are a few design motifs or ornaments that re-occur regularly in clocks and furniture of all ages, the most frequent of which are the Vitruvian scroll and the acanthus leaf. The work of Vitruvius, a Roman architect of the first century bc, was published in Italy in the mid-fifteenth century. His work was far more than the formal geometry of a snail-shaped scroll but that is the concept to which his name is now attached. The setting out of a perfect spiral is based on the concept of the Golden Section, a ratio of roughly 1.618. It is associated with various mathematical ideas including the Fibonacci Series, named after the twelfth-century Italian mathematician.

The Fibonacci principle is applied to construct a series of circular arcs that join to approximate to the same shape as certain natural phenomena, including the arms of spiral galaxies.

Acanthus mollis is native to the Mediterranean although it will grow in the British Isles; it was first represented in classical architecture in the Corinthian order, forming the capitals of columns. The re-emergence of neo-classical forms in European art in the medieval period is associated with the Renaissance, which used to be thought of as the rediscovery of ancient classical knowledge. Regardless of more recent historical theories about Europe after the Great Plague, representations of the acanthus leaf and the Vitruvian scroll have endured in furniture and clock cases since their arrival in Northern Europe in the sixteenth century.

Carving acanthus designs is a useful exercise for learners because it incorporates natural flowing curves.

Good examples of a fairly basic carved acanthus embellishment are often found on American drop-dial clock cases. The union of the round or octagonal dial to the drop that houses the pendulum is softened by a simple carved wooden ‘ear’. The detail is typically a combination of a pierced part with neo-classical acanthus leaves, often with simple incisions that give the visual effect of breaking up the flat areas.

The acanthus ornament is seen so often that sometimes it is hardly even recognizable. A lost ‘ear’ on a clock like this disrupts the whole appearance.

The following charts the progress and the pitfalls of a novice woodworker making a copy of an ear:

•  Step 1 Mark the outline on to a piece of card and cut out a template.

•  Step 2 Select a suitable piece of wood that will hold together well (in other words, one that will not tend to split along the grain). For American drop-dial clocks, the preferred wood is black walnut, a tree that is native to North America but somewhat inferior in woodworking properties to European walnut.

•  Step 3 Copy the outline on to the blank and cut out with a coping saw.

•  Step 4 Mark the main features of the carving, keeping in mind the flowing impression of the original. In the past wood-carvers were always taught how to hold a pencil to make the sketch designs: instead of holding the pencil between finger and thumb, with the palm facing down as for writing, the carver holds the pencil with the palm facing up.

•  Step 5 Carving only works well with really sharp tools – it is best not to spoil the effort by struggling with edges that are not surgically sharp. Cut away the deep features first and then attend to the finer detailing after. Use smooth continuous cuts as far as possible.

•  Step 6 Remove the excess wood that was left on the blank to allow it to be clamped to the bench.

•  Step 7 Finish by sanding but try to avoid softening the sharply carved edges. Finally glue a reinforcing strip to the back to strengthen the glue bond to the clock case.

This piece of European walnut should be ideal for carving but this is not always the case. The wood needs to have a dense nature for carving and anything that has a loose or biscuit-like texture should be avoided.

There is no rule for the direction of cut for a coping saw but most people find pushing easier than pulling.

After a few initial cuts you will get the feel of the wood and the grain. Only cut down the grain.

Work towards the bottom of the grain from both directions.

A few simple cuts with a sharp Vee tool will create the impression of the leaf. The cross-hatched area is a typical way of filling or texturing a flat area.

Reinforce the glue bond between the decorative ear and the case proper with a simple glue-block.

As well as carvings influenced by neo-classical designs, clock cases display a number of other styles. For example, in the mid-nineteenth century replacement cases for old longcase clocks often reflected the Victorian Jacobean revival. The heavily carved and dark-coloured oak cases are instantly recognizable as Victorian.

A Queen Anne Irish clock in a Victorian Jacobean Revival carved oak clock case.

Incised carving in an American walnut shelf clock of the 1890s. The detail on the left shows the combination of solid form and incised decoration.

A new style of carving appeared in furniture and clock cases in the late 1800s with geometric designs cut into flat surfaces. This incised style, which persisted until the First World War, is a low-cost decoration that is quickly achieved with a carver’s Vee tool.

APPLYING VENEERS AND INLAYS

There are specialist suppliers of veneers and inlays but modern products are most suitable for new clock cases because they are quite thin. Old hand-cut veneers are much thicker and, although they can be easier to work with, they can only be laid by pressing the freshly glued sheets with screw clamps or weights. A greater range of techniques is available for applying thin veneers, often including the use of heat to re-mobilize thermo-softening glues.

Adhesives

Animal Collagen Glues

Sometimes called Scotch glue, the animal collagen glue traditionally preferred for laying veneers is made from rabbit skins. All animal collagen glues are thermo-softening but susceptible to deterioration with moisture. They are the preferred option for conservation because they are similar to the original materials and they are reversible. They are applied hot (60 degrees centigrade), so they must be worked quickly, although heat can be applied after with a heated iron. The hot glue is spread with a brush and then, after the veneer is laid over the work, it is moistened with a sponge dipped in hot water and rubbed lightly with a hot flat iron.

A glue pot is used to warm animal collagen glues. The outer water jacket maintains the temperature at about 60 degrees centigrade. Overheating the glue will spoil it. Thermostatically controlled electric glue pots are available.

Thin veneers may be pressed on to the ground with a veneering hammer, squeezing the excess glue and air bubbles from the middle to the edges. Thick sawn veneers cannot be laid with a veneering hammer; instead, the veneer is placed flat and pressed into place using cramps (clamps) on flat softwood cauls.

Modern Hot Melt Adhesives (HMAs)

For large areas of veneer such as new clock cases, HMA is available in large sheets or rolls. It may be ironed on to a clean surface using the backing sheet to prevent adhesion to the sole of the iron, or it may be placed as a loose sheet under the veneer to which the hot iron is applied. The adhesive is a synthetic polymer, with some additives to stabilize the set glue. It is thermo-softening and reversible. Consequently, because it is so easy to use, it is the favourite veneer adhesive system for small workshops and hobbyists.

To make small veneer mends, a hot glue gun is used to apply a smear of glue to the ground. When the patch is placed into its correct position it is fixed by applying a hot flat iron to re-melt the HMA.

An ordinary domestic flat iron is used to melt the HMA on to the ground. The paper backing sheet is useful because nothing sticks to it.

Align the veneer and then apply the iron to re-melt the HMA. For larger areas protect the veneer with a piece of backing sheet.

Modern Water-Based Wood Glues

Modern water-based wood glues are either PVA or aliphatic resins. They are not ideal for fixing veneers. Expansion and shrinkage problems associated with absorption of water from the adhesive, followed by drying, mean that there is a risk that shrinkage cracks will develop in the veneers as the moisture content falls. They are not generally fully thermo-softening so they are not reversible, although some aliphatic resin glues can be softened with a hot iron. They absorb into veneers and can cause marking or blinding, which prevents the later absorption of wood stains or dyes.

Despite the disadvantages of using water-based glues they do allow the veneer to be slid into place and they are especially suitable (or can even be the best option) for fixing veneers to curved surfaces (see below).

Solvent-Based Glues

Liquid or aerosol glues (contact adhesives) can be applied to the surfaces to be bonded together; after the solvent has evaporated out, the glued surfaces bond immediately on contact. They are difficult to use because of the high risk of entrapping air bubbles. They are not reversible and are not recommended for any restoration or conservation applications.

Applying Veneers to Curved Surfaces

Fixing veneers to curved surfaces involves the challenge of applying pressure evenly to the curved surface. An animal collagen glue or water-based adhesive is spread on the ground and, once the veneer has been laid on, it is rubbed from centre to edges to remove air bubbles. The pressure is applied by placing a canvas bag filled with hot sand over the veneer, and then applying weights or cramps. The bags of sand distribute the pressure of the weights or cramps. Sand holds the heat for a long time and, for animal collagen glues, a moderate temperature only is sufficient.

The drop below the bottom board of this Vienna clock case has lost its veneer. The clock had been left in a damp outbuilding for years, leading to a deterioration in the glues and promoting a woodworm infestation.

Cut out the replacement veneer, allowing an overlap. This veneer is a reddish European walnut.

To trim the edge straight, position the veneer between two blocks, leaving just sufficient for planing.

The drop is an ogee profile which meets the bottom board perpendicularly. After spreading a water-based aliphatic resin glue, the top edge is laid using a softwood caul and two clamps.

It takes about an hour to heat a couple of kilograms of sand to hand hot. In the canvas bag it will apply heat and spread the pressure from the applied weights.

There are many applications where a flexible caul can be pressed over a curved surface. Straight-grained oak is suitable to prepare laths, which will bend to cover the ground profile. A piece of thick felt is placed between the veneer and the caul to distribute the pressure. Felt from old scrapped pianos is ideal.

The wavy shape of the bottom board of this typical Vienna is to be veneered with the grain running vertical like a cross-band. Glue is spread on the central strip of veneer.

The veneer is laid and pressure applied through a strip of felt.

Allow plenty of time for the glue to dry – at least overnight – then trim the excess veneer with a sharp chisel and finish with fine sandpaper. Take small slices, sweeping the blade towards the solid board.

Making Up Lines and Inlays

Composite inlay bands are available from specialist suppliers of veneers but, inevitably, the chance of finding modern inlays identical to those on old clock cases is fairly remote. There are a few readily available woods that are suitable for making inlay bands: the white woods of holly and sycamore; the brown woods such as cherry and various fruit woods; and the dark woods such as mahogany and so on. Black lines or bands are usually called ebony but bog oak is suitable.

Making up composite bands is a matter of gluing individual sheets of the chosen woods together to make up a composite sheet, and then slicing off thin strips.

Cut pieces of the desired thickness. Here, a whitish maple and black bog oak were used.

Clamp the composite between cauls and leave overnight.

Cut strips off the composite either with a fine-tooth saw or a sharp plane for use with very thin veneers. The inlay band should be slightly thicker than the surrounding veneers.

A veneer saw is useful for old thick veneers that cannot be cut easily with a knife and straight edge. Also useful are a couple of special tools for inlays, a home-made double knife and recycled chisel for cutting grooves.

In new work an inlay band is set into the veneer ground by cutting out a strip with a double knife and then removing the wood between the cuts. (The double knife is made up from pieces of old hacksaw blade inserted into a handle that has two saw cuts at the required spacing.)

Make up the double knife to fit the inlay exactly.

GILDING AND RE-GILDING

To apply the correct terminology, it could be argued that gilding is restoration, not conservation, because it involves returning an object to some former state and not merely preserving it. A contrary argument would assert that re-applying gold leaf would preserve the integrity of the object and, consequently, it could be construed as conservation.

Many years ago, the technique of fire gilding onto metal was widespread. It was done by applying a solution of gold in mercury (amalgam) and then heating to evaporate the mercury. Fire gilding is rarely used now because mercury is harmful to health and the environment. Ethical questions may arise for the conservator when the promoters or clients for conservation work specify fire gilding.

The application of gold leaf and synthetic gold leaf using water- or oil-based adhesives (sizes) is not hazardous and not difficult to master. The surface must be smooth and of an appropriate colour because gold leaf is very thin and slightly translucent.

Water gilding should not to be confused with applying leaf directly to a water-based size. Water gilding involves smoothed mineral surfaces and gives a bright reflective finish, which oil-size gilding cannot. It is more suited to articles such as picture and mirror frames where the surface to be gilded is built up, first with gesso – a mixture of fine white mineral and rabbit-skin glue – and then covered in a mixture of clay and glue that gilders call ‘bole’. The gold leaf is applied after the surface is wetted with a 50/50 mixture of water and isopropyl alcohol and, after it has dried, the fresh gilding is burnished with an agate or steel rubber or tip to yield a shiny metallic appearance.

For larger-scale re-gilding work, the point of using the bole is that it provides both a coloured base and a smooth surface. The admixture of rabbit-skin glue means that the gold leaf may be laid once the surface is wetted with the isopropyl alcohol solution.

For smaller patches where the traditional method is not vital to the project, water colour or acrylic paint in paste form (the sort that comes in tubes like oil paints) is ideal for preparing the surface. It is applied quite thickly and, after each coat has thoroughly dried, it is rubbed with fine abrasive paper and finished with 0000 grade wire wool to give a shiny surface.

An adhesive (size) is applied to the surface and after partial drying the gold leaf is applied. The result is generally as good as the preparation and the way that the size is applied: if it is painted on too thickly, the brush marks will show on the surface of the gold leaf.

The choices for gold leaf are either real 23.5 carat leaf or an alloy. Each of the leaf types is available either as loose leaf in books or as transfer sheet on a backing paper. Handling and applying loose leaf takes practice and for the amateur the transfer sheet is a much easier option. Once applied, 23.5 carat gold will not tarnish so it needs no further treatment. Alloy leaf will develop a tarnish when exposed to the air so, once it has been applied, it should be protected with shellac or wax.

In the simplest process an oil size is painted onto a prepared surface and left to become tacky. A one-hour size is about right for most small jobs. The transfer sheet is pressed on to the sized surface repeatedly until the entire surface is covered. It is less easy to burnish oil-size gilding so the surface will remain slightly matt. Any ball-ended tool can be used to flatten and burnish the finish.

Synthetic gold leaf is applied to a finial treated with water size.

Remove the excess leaf with a brush and burnish lightly. Synthetic gold leaf is a base-metal alloy so it will tarnish with exposure to air. Coating with shellac or wax will also tone down the light yellow colour.

PAINTING

In the past, lower-value clock cases were often finished in a simulated wood-grain effect. The surface was painted in a series of coats, with combs or coarse brushes being used to create the impression of wood grain. The technique was first used on English clocks, when it was applied to the pine cases of country-made long-case clocks from the mid-eighteenth century. It was used in American clocks later, from the mid-nineteenth century. Interestingly, cases with an original painted wood grain are now becoming scarce.

The original painted surface is vulnerable to damage and flaking but good restoration is within the capability of any hobbyist willing to experiment and practise.

Antique clock restoration specialist Tom Temple (xrestore.com) is very good at, among other things, applying painted wood-grain effects on to old clock cases. This is how he does it:

From the 1800s, clocks made for the mass market utilized a painted wood-grain finish to enhance the appeal of the cheaper base wood. This fragile finish will dry, crack and experience damage, but authentic repair is within the skill set of most craftsmen. (Tom Temple www.xrestore.com)

First, the old paint is sanded away and any necessary repairs are made. A coat of alkyl enamel provides an easily sanded base. (Tom Temple www.xrestore.com)

The first layer of the new wood grain is a glaze made of yellow ochre acrylic and polymer glazing medium. (Tom Temple www.xrestore.com)

Various acrylic colours such as Raw Umber, Burnt Umber and Burnt Sienna are used for the graining layers of the finish. A thin glaze is mixed for each colour. (Tom Temple www.xrestore.com)

Crude grain lines are created using a stippling stroke. (Tom Temple www.xrestore.com)

Mix different acrylic colours with glaze. (Tom Temple www.xrestore.com)

Once the basic shape of the grain lines is satisfactory, a darker brown glaze is used to add depth to the finish. (Tom Temple www.xrestore.com)

As successive coats of the glaze are applied, the grain begins to soften and look more realistic. (Tom Temple www.xrestore.com)

Again, use a stippling stroke to create a wood-grainlike surface finish. Continue to apply layers of glaze until the wood grain looks deep and rich. (Tom Temple www.xrestore.com)

Once the glaze is thoroughly dry, finish with shellac, using a hand rubber to produce a professional and period-correct finish. (Tom Temple www.xrestore.com)

With a bit of practice, it is possible to produce very realistic wood finishes using only simple tools. The complete technique is covered in much greater detail in Tom Temple’s book Extreme Restoration. (Tom Temple www.xrestore.com)

POLISHING WITH SHELLAC (FRENCH POLISHING)

Shellac is a natural resin, which is soluble in ethanol (also known as alcohol or spirits of wine). It came to Europe from the Far East after the establishment of the British and Dutch East India Companies but was not initially used in British furniture. Its use as a finishing agent in furniture and clocks spread from France and Northern Europe to the British Isles and elsewhere in the late eighteenth century (at about the time of the French Revolution).

Successful application of shellac polish requires a warm, dry and dust-free place. Plenty of light is also important, especially when the work is nearing completion, because a reflected light across the surface will highlight the faults and blemishes.

•  Step 1 Starting with the bare wood, a coat of linseed oil will seal the grain and make a better, smoother surface on to which to rub the polish. It is best to rub the oil on quite liberally and leave it at least overnight before removing ALL the excess with clean cotton rag.

•  Step 2 Make up a rubber using something like cotton T-shirt material with some absorbent material such as cotton wadding inside. (There is plenty of advice online on how to make up a rubber.) The size of the rubber should be in proportion to the size of the work and for clock cases it is often necessary to make a rubber with a point that will reach into angles. Avoid creases in the sole of the rubber.

•  Step 3 Charge the rubber with just enough polish so that when it is dabbed against a sheet of typing paper (or on the back of your hand) it just leaves a slight patchy mark – not wet and not dry. (Only by experience will you be able to judge the amount of polish required.)

•  Step 4 Put on the initial rubber of polish fairly moist because the first objective is to fill in or flatten the pores in the grain. That is why it should be rubbed on with circular strokes, crossing the grain and making sure that the edges are covered.

•  Step 5 Pressing and/or squeezing the rubber will let more polish out and on to the work and, as the rubber begins to drag, put a single drop of linseed oil on it and continue until the polish in the rubber is completely dry. The most common problem experienced by beginners is getting bogged down with too much polish on the rubber, which tends to stick to the surface and lift the polish back on to the rubber.

•  Step 6 It is important to keep the rubber moving when it is in contact with the work because shellac polish is its own solvent. Just one pause in the motion of the rubber is sufficient for the polish in the rubber to combine with the surface, making it stick.

•  Step 7 The polish will be sufficiently dry in a few minutes to repeat the process.

•  Step 8 After three applications of polish, the work can be set aside to harden (letting the methylated spirit evaporate is often referred to as ‘gassing out’). The rubber can then be stored in an airtight container.

•  Step 9 Returning to the work, perhaps a day or two later, you will notice that the surface is streaky, with dull or opaque areas in it. The streaks are from the track of the rubber and the opaque patches are the linseed oil coming out to the surface.

•  Step 10 It is possible to remove most of the oil from the surface with a few drops of turpentine on a clean rag.

•  Step 11 If your rubber has been kept in an airtight container, you could use it again for the next stage.

•  Step 12 Rub the finish with a pad of fine wire wool and then repeat steps 5–11 above.

•  Step 13 Leave the work aside for a few days in a warm, dry room to harden out.

•  Step 14 Rub again with wire wool and polish again with a more dilute solution.

•  Step 15 Finally, for a high-gloss finish, once the work has hardened out it can be burnished with a clean cotton rag made into something like a rubber. A couple of drops of methylated spirit will be sufficient. It is important to make sure that the methylated spirit is distributed evenly through the burnishing pad – it should not feel damp – as the merest hint of methylated spirit will be enough to soften the surface. Use a firm, brisk, circular burnishing action.

TURNING

Turnery in clock cases covers a wide range of items, from circular mouldings above the hood door of a longcase clock hood to all sorts of knobs and finials.

Turning both small and large parts is a regular feature of clock-case restoration. There are groups and societies of wood-turners who are usually helpful with one-off projects.

The same blank ten minutes later has become a finial for a Vienna clock.

A replacement ball is added to restore as much as possible of the remaining finial.

Making Half- and Quarter-Round Balusters (Columns)

Making half- or quarter-round balusters (columns) for the corners of a longcase trunk is quite straightforward in a lathe but proportions are vital and care in design will always be rewarded. A square section should be left at each end of the blank – this will be required later to stop the blank from twisting while it is quartered.

A neo-classical style often calls for balusters that are reeded or fluted in the style of classic architectural columns. It may be possible to make some modifications to a lathe, which will allow a travelling cutter to run the length of the turned blank. Alternatively, a jig is made up to mount the turned blank and cut the detail. In addition, a dividing plate will be required so that the blank may be indexed by the correct amount between each cut. The preferred cutter for flutes in this set-up is a point flanked by two semi-circular concaves rather than the usual form of a bead cutter.

Once complete, the turned and detailed blank is attached to a squared planed softwood slip and run through the band-saw, first to make halves and then again to make the quarters.

Capitals and bases are turned separately and quartered in the same way, ready for assembly into the case. Again, it is easier to polish prior to quartering and gluing up.

Classical Columns

Although columns in classical Greek and Roman architecture are usually about eight diameters high, the columns in early longcase clock hoods are typically more slender, at about twelve diameters in height. Another common way in which clock balusters differ from classical columns is the often pronounced cigar shape that is a concession to ‘entasis’.

The concept of entasis means that Ancient Greek and Roman architectural columns are not always straight and parallel and, although they mostly thin towards the top, they do not thicken out directly above the base. Ancient architects discovered that, in order to counter an optical illusion, a column should be made so that it was relatively thicker at about one third of its height.

Many of the formal design rules from the ancient world came to Italy at the start of the Renaissance, and with the rise in printing, those rediscovered rules eventually spread throughout Europe.

For various reasons it would be unusual to find entasis in trunk balusters but in hoods it seems to be the norm, although it is much exaggerated relative to classic design rules (often to the point at which balusters are exaggeratedly cigar-shaped). It should not seem strange that it is only the hood balusters that are modified for entasis. First, there is very little space available to modify a parallel trunk baluster, while on the hood the baluster is much smaller and less confined. Second, because of the position of the trunk baluster – well below eye level – the intended optical illusion would be lost in any case, whereas the hood baluster, at or just above eye level, would be ideal for such treatment.

Explanations about how entasis came to be introduced into clock cases involve perplexing aspects of social history in the late seventeenth and early eighteenth centuries. It is most likely that the customers for early longcase clocks were the wealthy and enlightened elite, familiar with the classics and European architecture. Consequently, it is not far-fetched to conjecture that the early clockmakers deliberately set out to appeal to those educated and enlightened customers, using classical design features, proportions and symbolism.

There is a pronounced entasis in the hood-door pillars of this early eighteenth-century clock. The hood balusters of early longcase hood doors are half- or three-quarter sections integral with the door. Hood balusters became free-standing in the second half of the eighteenth century.

The balusters are mostly, but not always, turned (square-section balusters are called pillars). The exceptions tend to be where reeded canted corners on the trunk are reflected by square-section hood balusters embellished with similar but smaller reeding. Depending on the architectural style of the whole, they may have bases and capitals, either cast in brass and then lacquered, or perhaps carved in wood and gilded. It is possible to find modern reproductions of brass capitals but they are not easy for the amateur to cast. Carved wooden capitals are far less difficult to make but the carving requires practice, very sharp tools and the right sort of wood. Lime (the Tilia species, not citrus lime) is ideal, as is a fruitwood such as apple.

Dividing a baluster into two equal halves is made easier by leaving square ends on the blank after the turning is completed. Three-quarter balusters that are found on good-quality early clocks are more difficult. The best approach is to fix a fence firmly to the baluster and then cut down with a fine-tooth saw. Make the two saw cuts on the waste side of the line to remove one quadrant and then finish with a rebate plane.

Barley Sugar Twists

Barley sugar twists (also known as barley twists or single twists) are a common feature in household furniture of the seventeenth to early eighteenth centuries. Although it is associated with post-Restoration furniture, the barley twist remained popular well into the mid- or even late eighteenth century, despite being, by that time, strikingly anachronistic. The odd thing about the barley twist in longcase clocks is that it is seen in the hoods of certain examples but, unlike other baluster forms, never in the trunk, with the exception of country-made cases and modern reproductions. A barley twist may be left- or right-handed and in a clock hood they are used as opposite pairs; early clocks with barley twist often have a quarter baluster of twist fixed into the back corner of the hood and again each of those has a chiral opposite to make a perfect mirror image.

Marking-out arrangement for a simple twist; the pitch and rotation are each divided into eight segments and the black curve is the initial saw-cut line. The first cut with the twisting gouge is from the red line, working from right to left. The piece is then reversed in the lathe and the next cut is from the green line, again working from right to left.

Any sort of twist can be made between centres in a lathe, turning the work by hand on to the tool. The setting out is critical. The blank is marked out by scribing circles every one-eighth of the pitch and lines along the blank at one-eighth revolution. The initial cut line is drawn from intersection to intersection and then two parallel secondary cut lines are marked one division each side of the initial cut line.

Tools for making twists (from left): twisting gouge, scraper, two paring chisels, rasp and sandpaper.

The tools for making twists are different from ordinary turning tools. They are short-bladed for better control and, unlike turning tools, they are honed to be very sharp.

A continuous saw cut is made along the initial cut line to a depth of a few millimetres. Next, the twisting gouge is used to open out a groove by cutting from the secondary line into the saw cut.

The bine comes to a sharp point where it is intersected by the cove, which is turned conventionally after the twist is cut.

The twisting gouge is only used to cut down the grain so the work must be reversed in the lathe frequently. The tool should never be pushed, but simply held on the tool rest and the blank rotated on to it.

A cove or groove is turned at each end so that the bine (the projecting part) of the twist starts at the cove with a sharp edge.

Large Turnings

Large items such as the hood of a wall clock can be made on a lathe that is suitable for bowl turning. Otherwise a blank is mounted on to a large face-plate. The same arrangement is used to make up large circular mouldings, which are common in longcase clocks with break-arch dials.

A replacement hood made up for a wall clock with a 12-inch (30cm) dial.

The reverse of the same hood shows the eight segments glued and dowelled together.

Chapter 4

Making a New Clock Case

This chapter describes in some detail the construction of a replica case for a mid-eighteenthcentury provincial longcase clock. The original case had long since disappeared and we were commissioned to make an appropriately styled case so that the clock could recommence its original two roles as principal domestic timekeeper and as a significant piece of decorative furnishing.

THE CLOCK

The clock for which we were to make the replacement case originated in the Wiltshire village of Redlynch, about 7 miles from Salisbury. We do not know who made the clock case but the clock part was made by a local clockmaker, Peter Bower, in the archaic posted or bird-cage style of construction. Not much is known about Peter Bower; his entry in the Brian Loomes directory (Watchmakers and Clockmakers of the World) is brief and inaccurate: ‘Bower, Peter Redlinch, Somerset c 1740’. The UK and Irish clock- and watch-makers’ online historical research site is more informative and it seems that there are two villages called Redlinch (aka Redlench and Redlynch):

Bower, Peter of Redlynch, Redlench or Redlinch, Wiltshire.

Bower, Peter of Redlynch (Redlench/ Redlinch as the 18ct century engravers spelt it). This clockmaker was working there about the 1739 to 1795 period.

Peter was born about 1715 and married Susannah Bayly in 1739 at Salisbury, he was listed at this time as a blacksmith living and working in Downton, Wiltshire. Peter and Susannah had six children. James (1743– 1787), Sarah (1747), William (1751, married 1776), Hannah (1753, married 1775), Thermulhis (1756–1779) and Peter (1759–1774).

He died in July 1795 at the age of 80. Most of this prolific maker’s clocks were 30-hour clocks in Oak cases, but he is known to have made at least 2 musical clocks and an 8-day clock.

One of Peter’s sons, William followed his father into the clock making business although no clocks by him are known.

Simple clocks of this type are associated with a social class that included wealthy farmers and merchants. The detail of the engraving of the central part of the dial (the zone) is similar to that on other extant examples of Peter Bower’s work.

The English bird-cage movement – the wheel work supported in a frame with three vertical bars and the strike train mounted directly behind the going train – was a medieval system that survived well into the eighteenth century in the provinces. Clocks of this type have become collectable and their value has increased in recent years.

The clock, of 30-hour duration, is driven by a single lead weight of about 5 kilograms; it has a brass 10-inch square dial with a 1-metre, one-second pendulum and a single hand. (There was probably little point in having a minute hand in mid-eighteenth-century rural Wiltshire).

DESIGNING THE NEW CASE

Having researched the clock dial and movement sufficiently we decided that the appropriate case would be plain, made up in oak with only minimal embellishment. In order to devise the most appropriate design, the best approach is usually to locate a complete clock of similar age, status and type and then use that case as a model for the design of the replacement case. We also looked for complete clocks by Peter Bower.

We located a potential good match – an oak provincial clock case, ostensibly by a Norfolk maker, Benjamin Shuckforth, after we noticed that apparently that case was not original to the Norfolk clock. Despite questions about geographical accuracy we concluded, by looking at other Peter Bower clocks, that the style and design were reasonably close. The Bower clocks that we traced used half balusters on each side of the hood door and, although this quite common feature was not present on the Shuckforth case, we nevertheless planned to add balusters to our new case.

Clock by Benjamin Shuckforth of Diss in Norfolk – a similar 10-inch dial, one-hand bird-cage clock. The overall height is only 1.94m (76in), which is typical for clocks for country dwellings in the mid-eighteenth century. This was never a clock for the land-owning classes.

The dial does not quite fit the bezel in the hood. It is obvious that this case was not made for the Shuckforth clock but is, in fact, a later, sympathetic replacement.

The door (always hinged on the right) is 870mm × 200mm. The trunk is only 300mm wide, wide enough to accommodate the swing of the pendulum and strong enough to support the movement and its weight (5kg).

A Peter Bower clock in what we think is an original case, with half balusters on each side of the hood door. (Wiltshire Clocks www.wiltshireclocks.co.uk)

Detail of the dial of the same clock. Note the similarity in the subject and execution of the engraving. (Wiltshire Clocks www.wiltshireclocks.co.uk)

Working Drawings

It just is not possible to make a long case without working drawings. Everyone works differently but one useful approach is first to make sketches of the various elements and then to prepare detailed working drawings.

The availability of computer-aided drawing and design software can make the job easier because it allows unlimited editing and accurate dimensioning. Conventional drawing can clarify thoughts about how the elements will be combined and is useful for making quite detailed drawings. Start with basic sketches.

Rough sketches are a really good way of analysing the detail and relationship of several components. This sketch shows how the seat-board is supported on the extension of the sides of the trunk.

Step 1

List the few basic dimensions that will be determined from research:

1.  The overall height, made up of the height to the top of the trunk plus the height of the hood. They form an aesthetic composition so they have to look right together. The different elements should not be designed in isolation.

2.  The height of the seat-board above the top of the trunk moulding, more precisely, the position of the dial relative to the bezel behind the hood door. (The dial should just fit behind the wood bezel of the case hood.)

The dial dimensions will dictate the width of the hood and hence the width of the trunk top moulding. It will also dictate the width of the trunk and the width of the base. Behind the dial the movement is fixed to a seat-board, which is some fixed distance above the lower edge to the dial. The hood rests on the horizontal surface of a moulding at the top of the trunk.

The shape and proportions of the trunk are characteristics of the case that should conform to the whole. Early clocks are slender and elegant but clocks made in the nineteenth century, especially in northern England, tend to be large and wide.

An understanding of the geometry of the sliding hood, the hood door and the dial is crucial.

The base (sometimes called the socle) is usually about 100mm wider than the trunk but it will vary according to style and date. Not all bases are rectangular, and not all have a vertical emphasis. The base is supported on either a plinth or feet, or a combination of both.

Step 2

Research similar clocks and make sketches of the arrangement of the dial, hood and top trunk moulding. Plenty of thought and care in the preliminary design sketches will yield results later. Pay particular attention to status of the dial: a high-status clock would have been put into a high-status case, while clocks such as our Peter Bower one-hand clock were made for people of more modest means.

Bear in mind that a good clock case, like any good piece of furniture, is the meeting of the craftsman’s hand and the artist’s eye. Good design, whatever the subject, successfully makes compromises between the aesthetically pleasing and the functional.

It is useful to start with rough sketches and then re-draw them later with more detail.

Step 3

Convert the design sketches to working drawings. Although electronic drawing or computer-aided design (CAD) has a significant role in the conservation and restoration of clock movements, pen drawings are useful and easy to produce and modify.

Polyacetate drafting film is the preferred medium for hand-drafting accurate, stable drawings. It is quite robust and will stand erasing and re-drawing, and its relative transparency makes it easier to trace from or onto. However, for preliminary general arrangement sketches and little detail drawings, squared or plain paper is sufficient.

Electronic drawing has many advantages in clock-case work; the drawing environment can support photographic images so pictures of similar clock cases scanned from reference books may be inserted, scaled to the actual size and traced to produce rough designs from which the accurate drawings are made.

One early design requirement is a decision on the thickness of the timber sheets and other components that will be used in the construction, and the dimensions of the two principal moulding sections: the trunk and base mouldings. For our project we have followed the thicknesses in the model case as far as possible – the oak sheets are quite thin, at 8mm, with the result that the case is surprisingly light.

One feature that is easy to overlook is the method of joining the backboard, sides and front of the trunk. The vertical joints are usually masked as much as possible and the method of joining will have a direct impact on the width of the front and back components. The joints should be designed so that the components can be cut out accurately.

Often the design calls for a more complex arrangement to obscure the vertical joint between front and sides, including canted corners or inset quarter balusters.

Two horizontal sections, one through the trunk and one through the base, will usually make sense of the sheet components and how they will be joined.

There is plenty of choice in electronic drawing software, from expensive industry standard products to freeware. The drawings do not have to be in 3D but the ability to draw in natural scale and add dimensions is very useful.

A rebated or ploughed joint to fix the 8mm-thick oak sides to the 17mm-thick back-board.

Later clocks are more likely to rely on glue blocks that were fixed into the inside angle to stiffen the joint.

Step 4

Refine the detail.

Making a sketch or accurate drawing of every joint will help to clarify the relationship of the various components and to eliminate mistakes. Always follow the golden rule of woodworking: ‘Measure twice, cut once.’

Inset balusters in the trunk hide the vertical joints and provide an opportunity for baroque embellishment.

The Trunk and Trunk Door

The dimensions of the trunk door are a characteristic by which longcase clocks can be dated and even placed approximately in their geographical context. Because of the visual prominence of the door, it is an element that requires correct detail. Thought should also be given to the make-up of the door – whether it will be a single sheet of a stable wood such as mahogany or wainscot oak, or of a framed construction, as was frequently used in early doors that were intended to be veneered.

Early cabinet-makers discovered all sorts of ways of making their products look lighter and more elegant. The characteristic half-round bead applied to most early London-made trunk doors is one example of a feature that created that illusion. The applied section is not particularly difficult to make and its purpose is both aesthetic and functional. While it enhances the appearance of the door, it also protects the delicate edge of the veneer that would otherwise be exposed to damage while the door is opened and closed.

Case-makers adopted various designs in order to provide a barrier to prevent the ingress of dust into the case but in general the door partly overlaps the front surface of the trunk. Our door will follow the model with a simple drop quarter round (see B, diagram below). From that we can see that the thickness of the oak sheet on the front of the case is about 10mm.

Different styles of forming the dust barrier on the trunk door: ‘A’ was used in London clocks up to the 1730s; ‘B’ was adopted for our oak case, the same as the model case. ‘C’ is 18th century and ‘D’ is 19th century.

Plain plinth or shaped feet? The deciding factors are date, status and region. In this South East Midlands clock of the mid-eighteenth century, the maker has relied on the figure in the oak panels of the base. The front panel overlaps the sides so the vertical joints are visible only from the side.

Base Detail

The base section is a matter for careful planning. In early clocks it may have a horizontal emphasis, often tapering in at the top. The trunk door is the largest plain area visible from the front, so a case-maker would look for a way of reducing the massive appearance. Cross-band and inserted or raised panels are common, but veneer inlays and marquetry were also occasionally used.

Hood Detail

There are two basic shapes for the dial: either square or with an arched top where the base of the arch is a little narrower than the square of the dial (a break arch). The break-arch dial lent itself to the flowing curves of the neo-classical style. The hood requires very careful design to ensure that it is in harmony with the whole and that the dial will be presented at the right height. Correct calculation of the seat-board height is crucial because the lower edge of the dial is always below the top of the seat-board, but roughly 35–50mm above the bottom of the door, which is itself above the top of the trunk moulding.

A rare and valuable early London-made clock fitted into a mediocre but later case of the wrong dimensions. The dial is positioned too low within the case, with the result that the bottom edge is obscured and there is a gap along the top edge.

SOURCING THE MATERIALS

Old wood salvaged from scrapped furniture and the like is an important source of wood both for restoration work to old cases and as material for making new cases. However, there are many applications for new wood, especially the softwoods that are used to make a backboard (if wainscot oak is not appropriate).

Softwoods are used for the backings to the major mouldings, base framing, glue blocks and hood tops. They tend not to keep their natural ‘woody’ properties in the same way as the hardwoods, and no wood seems to survive painting, which renders it unworkable and biscuit-like in texture. Consequently, new softwoods are usually preferred. However, where it is necessary to use large sections of the best-quality old pine, a useful source is found in architectural salvage and items such as old grand pianos. (Unlike clocks, grand pianos do not improve with age and are often available at scrap prices.)

The European hardwoods are mostly available as new stock. Oak is not sawn specifically to reveal the characteristic wainscot or quartersawn figure that is so widespread in old clock cases but saw-mills are often sympathetic.

Mahogany and other exotics are widely available as scrap furniture but walnut is surprisingly difficult to find and new wood is often the only alternative, especially since walnut is a favourite of the European furniture beetle (woodworm, or Anobium punctatum). Unless there is some special reason, American black walnut, Juglans nigra, should be avoided as a substitute for the European species Juglans regia. They are very different, not only in appearance, but also, more importantly, in workability. European walnut, along with true mahogany Swietenia mahagoni are the two woodworker’s woods.

For our case construction project we located some salvaged pine for the backboard. For the oak panels and sheets we asked a saw-mill to cut locally sourced oak into thin boards. Actually, imported North American oak would be an easier material to use than locally sourced because it is straight-grained, relatively free from knots and far easier to work.

CONSTRUCTION

Step 1 The Trunk

Putting together the backboard, the two trunk side panels and the front (the trunk door frame assembly) is the starting point. Although the backboard may seem to be the logical place to start, it is helpful to make up the front section first.

The four components that will frame the door and define the width of the trunk are jointed together. The front section will also include any provision at the vertical joint between front and sides.

A rebated joint is the strongest method of fixing the side sheets but it will then be easier to attach the glue blocks after the side sheets to ensure best contact.

It is important to get joints square. When the mortise is cut in the vertical stile, mark the tenon on the end of the cross-rail. A marking knife gives a sharp line.

Using a sharp chisel, convert the knife cut to a small Vee cut that will define the shoulder of the tenon.

The Vee cut will guide the tenon saw to give a sharp edge to the joint.

Use the tenon saw lightly to cut out the tenon. Too much pressure will turn the cut on to the line of the grain.

Oak can be a contrary wood to work, but sharp tools will always prevail.

Trim the tenon with a sharp chisel until it fits firmly. If the tenon is too thick, there is a danger that it will split the stile as it is forced home.

The joint should close straight and true with the front faces flush.

With the front assembly glued up, the side panels are rebated and the four main components of the trunk are then ready for assembly.

It might look like extra work but the traditional rebated joint used by the early makers guarantees a strong joint and makes assembly much easier.

Cut out the shape of the backboard without the widening at the trunk and mark out where the side sheets will be attached. For a simple glued lap joint, fix the glue blocks to the backboard first and, once the glue is cured out, glue and clamp the sides to the backboard.

As the sides are clamped to the backboard, check the squareness of the construction. The front section is then fixed to the sides, making sure that the rebate joints are properly engaged over their full length

Once the trunk is fixed to the backboard, the base will add stiffness to the construction.

Step 2 The Base

The quite fragile backboard and trunk assembly should be consolidated as soon as practicable by attaching the base section, which will prevent any deformation.

Two frames are made up and attached, one at the base of the front and side sheets, and one at or near the lower edge of the backboard; if any provision for treatment of the vertical joints is required, it should be included in these frames.

Infill pieces are attached to the backboard and the base framing and the base sides are offered up to the base frames.

Square and true: at this stage of the work the construction is slightly fragile. The stiffness is ensured by adding the base.

Framing for the base must be strong enough to resist twisting. Additional rigidity is provided by widening of the back-board.

The framing for the base is attached: the upper frame which is fixed to the lower end of the trunk is left open at the back to allow the clock weights to pass and ¾in square glue blocks are inserted between the upper and lower frames at the front corners. Infill pieces are added to the widened part of the backboard.

Proper clamping is essential to make sure that the glue line is microscopically thin.

The method of attaching the base sides sheets will depend on the nature of the vertical joint and any provisions to mask it. If a cross band is used, the thickness of the sides will have to be allowed for when the front panel is cut back to accept the cross-band veneer.

The side panels are fixed on first – the outside vertical joint will be visible only from the side.

With the base front panel glued in place the edges are trimmed back flush with the side panels using a sharp block plane.

The 65mm width of the wood is sufficient to accommodate the width of the moulding.

Other forms of edge treatment include mitres and chamfers, which were often used by a case-maker to show off his skills and advertise his services to potential customers.

The base construction terminates with either a plinth or feet or, occasionally, a plinth that is cut away to give the impression of feet. The purpose of the plinth is to reinforce and protect the lower parts of the base. Within the base, a solid dust sheet can be added. This will stiffen the whole structure by restraining any tendency to twist or deform, as well as preventing the ingress of dust into the case during household sweeping.

Step 3 The Base and Trunk Mouldings, Lesser Mouldings and Edge Treatments

Case-makers used their own tools to create mouldings so there is an almost infinite variety. There are usually five or six different mouldings in a longcase clock – the plinth; the top of the base; the top of the trunk (under the hood); the hood base (dust seal); the top of the hood; and an over-sailing or cornice – as well as the minor mouldings, which are small sections that break up the massive appearance, soften edges and give harmony.

Top of Base Moulding

The compound mouldings fixed to the top of the base framing used to be called French mouldings. They perform two tasks: first, they contribute to the stiffness of the structure by reinforcing the joints; and second, they are a neat and elegant way of uniting the two sections. Although almost all the base moulding profiles conform to a universal pattern with similar dimensions, it would be unusual to find identical examples, as individual case-makers used their own individual tools and judgement.

The simplest tools are often the best, as long as the edge is sharp. A plough plane is adaptable and it is one of only a few planes we use for nearly all clock-case mouldings.

Convex sections of moulding can be formed with a flat-soled plane in a series of cuts. An ordinary smoothing plane will not reach into the root of the Vee cut (see below) and a steel rebate plane is useful to finish off that detail.

From the template, the position of the division Vee cut is marked and a plough plane is prepared with a Vee blade.

Oak is notoriously difficult to work, even with a very sharp edge, and the Vee cut will tend to wander slightly. This will be corrected later.

A simple steel smoothing plane will form the convex surface.

The blade of a steel rebate plane is exactly at the edge of the sole, allowing it to trim and clean up the Vee cut and blend the Vee cut into the convex section.

This round-soled moulding plane has been adapted from another form. It is easy to use in conjunction with an adjustable fence. The result it gives is proportional to the sharpness of the blade.

Keep tools sharp. The quality of the shavings will tell a lot about the sharpness of the blade. A very thin but continuous shaving indicates a very sharp blade and incidentally will clear the throat of the plane without choking it.

The fence is packed out with a thin strip of wood to index the plane to the left.

A second, thick strip is added to the fence to index the plane to the left, widening the rounded concave section of the moulding.

The concave cut is finished off freehand with a very fine cut on the moulding plane.

Simple round-soled moulding planes are used to form the concave profile. Everything to one side of the initial Vee cut will be concave and everything on the other side is convex. A fence clamped to the work and the bench is used to guide the planes and it is relatively easy to modify the radius by adjusting the fence.

There is a relatively easy method that avoids the trouble and expense of tooling a spindle-moulding machine in order to cut the precise desired profile:

1.  Cut out a steel template which will be used as a gauge to check the progress of the work. (Our own preferred method is to use a piece of annealed ¹ ⁄16th gauge plate to make the template, which could be hardened and tempered to make it into a scraper for checking and finally finishing the work.)

2.  In selecting the piece of wood to work, try to find a cut that shows off the best figure. Composite and large mouldings are made up with the longest width aligned with the flat edge of the wood.

3.  With a blank about 1–2m long in the bench vice, mark out the division in the moulding, which is a 90-degree Vee cut roughly down the centre.

4.  The roughly 45-degree angled plane at the top of the moulding is formed using a bench plane, checking the angle periodically with a bevel gauge.

5.  As the work proceeds, it is checked with the template/scraper and then finished off by scraping or sanding, starting with coarse paper of about 80-grit size.

6.  Fine sandpaper (about 300-grit size) will flatten the surfaces to a point at which they will be ready for polishing. Care should be taken not to over-round the sharp edge in the ‘step’.

A longer plane will give a more even surface on the canted surface on the right that will eventually form the top surface of the moulding.

Finish with progressively finer sandpapers using whatever profiles fit the shape.

The backing strip saves unnecessary waste and provides a more effective gluing surface.

The backing strip is glued on to the moulding to make up a composite and the entire piece is shaped to give the desired final profile. A band-saw is a useful resource for any woodworker but these angled surfaces can be formed quite easily with a sharp bench plane.

It can be easier to colour and finish the moulding prior to cutting mitres and gluing on to the clock case because a surface coating of shellac or wax polish will allow any excess glue to be removed without marking the work.

The Top of Trunk Moulding

The trunk moulding is almost always a concave profile, except on very early longcase clocks, but the profile is rarely circular. Traditionally, the circular forms of mouldings, either convex or concave, were known as Roman, while the more complex curves were referred to as Greek. Again, a steel template/scraper is useful to check progress and keep the profile uniform.

Transfer the shape of the moulding on to the wood and start to form the section.

Keep checking angles and to finish use a very fine cut by adjusting the depth that the plane blade protrudes below the sole.

The shape is somewhat simpler than the previous profile but the technique is effectively the same.

The top of the trunk moulding has a vertical section outside of which the hood base moulding closes.

Keeping the angles correct will save problems later, so use the bevel gauge frequently.

The lower edge of the trunk moulding and various other parts of a case are often embellished with a subordinate moulding. This is made up either using a tonguing plane or a small bead moulding plane, or it is combined with the major moulding.

A small convex ovolo form at the base of the top of trunk moulding is shaped with a small moulding plane but it may be possible to find old moulding shaves (sometimes called sash routers because they are used to form the glazing bars of sash windows). In operation the ovolo shave runs at an angle to the work, so it is always pressed firmly into the wood. If the grain proves to be contrary, the tool should work equally well from the opposite direction (depending on the accuracy of re-sharpening).

A Preston ovolo shave – not an easy tool to find, but easy to use and effective.

A sharp edge and a thin cut is the secret with all moulding planes and shaves – little and often is best.

The finished profile. As often happens, a splinter broke out near the end. Always expect to have to discard several centimetres from each end.

The top of trunk moulding does not always have a softwood backing, especially in older clocks. As a result, because the planed surface is glued to the trunk panels, it should be as uniform as possible.

As the top of trunk moulding is glued to the trunk, it is vital that it is set absolutely square and true, because the hood will rest on the upper surface of that moulding.

Step 4 The Hood and Seat-Board

At this stage of the work, the hood will be supported by the top trunk moulding fixed to the trunk. The vertical extension of the trunk side panels will form the up-stands that will support the seat-board. It will be necessary to calculate the degree by which they should be shortened so that the dial exactly fits the hood.

The easy way to proceed is to make up the base and front of the hood and then offer it up to the case.

The Hood

The hood is required to be rigid and dust-proof but still reasonably light because it will need to be removed from the trunk occasionally. Structurally, it is difficult, being in simple terms a cube that is open at the back and the base, with a large opening in the front for the door.

In our case project, we followed the model exactly so that the front of the hood, the bezel (which is in effect a door frame), is fixed to the bottom cross-member of the hood frame first. The bezel is the key to the hood design. Once the bezel has been set out in the design drawings, all the rest will follow. The purpose of the bezel is two-fold: first, it covers the gap between the dial and the hood enclosure, keeping the hood dust-proof; second, it stiffens the hood, preventing skewing distortions. It performs that latter role almost unseen and unrealized but, without an effective (in other words, properly attached) bezel, the hood will be extremely fragile.

The dial fits a rebate in the back of the bezel, so the easy way to proceed is to use a template cut to the same shape as the dial.

The 8mm-thick oak panels of the bezel are fixed to the front of the softwood frame cross-member.

The width of the bezel is almost the same as the hood door so that when the door is closed, the bezel is effectively obscured. Square-dial clocks rarely exceed 13 inches across the dial and 1½ inches width in the door framing.

The bezel is glued together on the hood frame and provides an instant means of estimating the correct height for the up-stands.

It is easier to prepare the openings before the hood is assembled. The wood is fragile until the hood framing is glued on.

In order to construct the rest of the hood, the side panels are prepared. Early cases tend to use a small glazed aperture, a window, on each side panel of the hood to give a view of the movement. The bottom of this window should be above seat-board height.

In our clock case we copied the dimensions of the model and then just checked the height of the bottom edge before final marking.

Cut on the pull stroke with a coping saw.

Pare away the rough surface to give a clean smooth edge.

Use a skew (dovetail) chisel to get into the corners.

The panel is drilled near the corners in preparation for cutting out.

Coping saws do not leave a smooth, straight edge, so it is wise to cut just inside the line, leaving enough to clean a straight edge after.

The glass in these windows will be about 2mm thick so it is necessary to mark up and cut a rebate to take the glass, allowing about 4mm overlap of the glass all around. A neat rebate may be formed by cutting into the marking line with a sharp chisel to form a flat Vee cut, and then using the shoulder formed that way to shape the rebate.

The rebate must be deep enough and wide enough to hold the glass.

Surgically sharp tools will give a clean crisp finish and make the work pleasurable.

Returning to the hood front, it is now possible to mount it dry on to the top of trunk moulding of the part-assembled case and check that all is satisfactory.

A 17mm thick seat-board will span the up-stands and the dial should just enter the rebate in the back of the bezel.

Check that the fit is reasonably square because the hood must slide easily off the trunk. Corrections to the bottom edges of the side panels may be made using a block plane prior to gluing up.

Solid pediment sides are intrinsically stronger and easier to construct, but the disadvantage is in the additional weight.

The side panels are checked and then glued to the hood bezel assembly. The construction is stiffened by adding the overhanging pediment parts to the sides. In this case we again followed the model, using solid wood for the sides of the pediment.

The Seat-Board

As a general rule, the seat-board of an 8-day clock is loose while that in most 30-hour clocks is fixed to the up-stands. The up-stands are trimmed and the seat-board fixed.

The dial is not always square and true to the movement so occasionally the seat-board will be deliberately off-horizontal. It is the dial that should be true, not necessarily the movement.

The up-stands are trimmed to the correct height, and care should be taken to ensure that the cut is made square front to back. For some reason, inaccurately cut up-stands, often with packing strips, seem to be a feature of longcase clocks. Whether as a result of the clockmaker’s lack of skill with wood when he originally fitted his clock to the case, or because of height adjustments following a replacement seat-board, skewed saw cuts tend to make the clock movement unstable. Such instability can give rise to erratic behaviour and poor timekeeping.

The seat-board is cut out to accept the protrusions in the bottom of the clock movement, and the back of the dial. Holes are drilled through for the chain that will support the weight that drives the clock.

Place the clock movement with its dial on to the bezel. The dial should fit easily into the rebated bezel. Measure down from the underside of the movement to locate the position of the top of the seat-board.

Trim back the up-stands for the correct seat-board height.

Completing the Hood

The rigidity of the base-plate is quite obviously critical as is the fixing of the side sheets to that base-plate. Different approaches and styles of fixing are indicators of the origins of the case and of the skill and training of the case-maker. The classic cabinet-making method is to cut tenons into the lower edge of the side sheets so as to mortise them into the base-plate. A more provincial approach involves nailing the side sheet to the inner face of the base-plate using a separate strip of wood for the sliding joint that allows the hood to be slid forwards off the trunk.

In our clock case, the strength in the hood and its resistance to torsional deformation are derived from the stiffness of the glued joint between the side panels and the bezel, which is itself stiffened by cross-members above and below.

The mouldings contribute greatly to the rigidity but only if they are well fixed and accurately mitred. Additional strength and rigidity are given to the hood structure by fixing a solid top panel to the pediment and also by stiffening members at the back of the side panels.

The original case we are copying has an outward return at the back of the side panel. It appears that the quarter-round section was finished with capital and base, which are now missing. We have arranged the equivalent part of our case hood to have a member glued to the back edge of each side panel. With a strong glue bond, the stiffening effect of these simple additional parts greatly strengthens the whole hood structure.

The mitred moulding reinforces the construction while completely altering the appearance from crude and massive to elegant.

The stiffening flange fixed to the back of the hood side panel (it has lost its decorative terminations).

Stiffening flange ready to be glued

The last piece of the structure of the hood is a solid 10mm thick sheet of deal glued and pinned across the top of the pediment, inside the over-sailing moulding (a moulding near the top of a construction, which projects outwards). The top board prevents dust-fall and resists any twisting deformation. It is not unusual to find old clock cases in auctions and antique shops on which the stiffening effects of the bezel, the top dust-board and the side panel returns have been lost. Clock cases that have suffered those losses are extremely fragile and very susceptible to further damage.

The top dust-board provides a good opportunity for a little embellishment. We decided to copy the two spiked orbs that adorn the original Benjamin Shuckforth case. The idea was to make orbs or balls in keeping with the country nature of the clock case so they were turned from wood and then gilded. As with the hood-door balusters, European walnut is an ideal wood for making fine detailed parts.

The blank was turned between centres in the wood lathe and then finished by securing in a three-jaw Jacobs chuck.

Walnut is a good choice of wood for making finial because it is dense and cutting leaves a smooth finish.

Sand lightly in the lathe but do not wrap the sandpaper around the revolving work.

In order to provide a good flat surface for gilding, the fine sanded orbs were painted with a thick watercolour paint, to prime the surface and make it smooth enough for gilding. When the watercolour paint was properly dry, the piece was put back into the lathe and the surface was burnished with a small pad of fine wire wool. Care had to be taken not to let the wire wool catch in the rotating work.

A watercolour paste will seal and flatten the surface ready for gilding.

A one-hour oil size and pure gold leaf not only give a better finish than gold paint but also will not tarnish.

When the surface was smooth, a gilding size was applied; an oil size is preferable, as it will not upset the watercolour finish. When the size was just tacky, the gold leaf could be applied. Real gold leaf (23.5 carat) is a little more expensive than synthetic alloy, but it is easier to work with. It is not as easy to burnish gold that has been placed on an oil size but nevertheless the effect was satisfactory for the social context of the clock.

Check that the finials on their bases are about right within the proportions of the hood.

After being mounted on walnut bases, the gilded orbs were fixed to the dust-board. As final addition, a lath between the orb bases gave a certain harmony to the composition.

The Hood Door

Hood doors for break-arch clocks are slightly more awkward to make but the principles are the same. The opening in the door is effectively the same as the bezel (that is to say, the same as or slightly smaller than the dial). It must be light but strong and resistant to twisting because it will be glazed with very thin glass.

In our clock case, the outer dimensions of the hood door are identical to those of the bezel. The material is 12mm thick and the vertical stiles are wider than the horizontal cross-rails because they must accommodate the proposed half balusters.

The optimum joint design is a blind mortise and tenon that leaves sufficient land near the end of the stile. The mortise penetrates only approximately half way through the stile in order to retain as much strength as possible in the vertical stile.

The mortises are cut at one-third of the thickness of the stiles (in other words, about 4mm).

Score the length of the mortise and make a series of cuts with a sharp chisel, keeping the vertical alignment true.

As the work proceeds, check that the joints are square and that the part assembly will lie flat. If it does not, make small corrections or re-do the work. The door must be flat, otherwise the glass will be stressed.

Reasonably neat work. It is important that the bottom of the tenon is as far as possible from the end of the stile so as to reduce the risk of the mortise propagating splits along the grain.

The hood-base moulding has been fixed on in order to check the clearance of the door. The moulding projects below the hood frame to form a dust barrier as the hood is closed on to the trunk.

Once the basic door is complete and glued up it can be offered up to the hood and trimmed if necessary. It will now be ready to have the half balusters attached.

The Hood Balusters

The hood balusters in early longcase clocks are usually attached to each side of the door. Later, with the introduction of trunk balusters in the mid-eighteenth century, the corresponding hood balusters not only reflected the shape of those used in the trunk but were, by then, usually free-standing and independent of the door.

Our balusters were designed to be fixed to the door in the earlier style and, although Peter Bower almost certainly made the clock after the turn of the century, case styles in isolated rural regions tended to lag far behind London styles. We also have direct evidence that integral balusters were used in two other Peter Bower clocks but we were unable to find a clock by him with separate balusters.

Apart from the backboard and some framing, the clock is oak, but to make the turned balusters we selected a piece of European Walnut, partly because it works better than oak and partly because it seems to be a wood that was used for this type of more detailed embellishment.

Walnut turns well with a fine finish, so it is the preferred wood for balusters and other pieces.

A band-saw is not absolutely necessary but it is a definite advantage. Otherwise, use a sharp saw gently to achieve a straight cut.

The baluster was finished in the lathe and then run through the band-saw to divide it into two equal sections. Finally, the half balusters were glued on to the door; the width should be carefully arranged so that they are just slightly narrower than the door stiles, which should be visible at the inside edge (nearest the glass).

The glass bead is made up as strips of 4mm × 6mm with a half-round on one short edge. It is mitred into the inner face of the opening and glued into place. If it is necessary to pin the beads in place, allow the glue to dry first.

Half balusters glued and clamped in place.

The glazing bead is pressed into place while the glue sets by the use of stressed lathes.

The Hood-Door Hinges

Hood-door hinges always seem to cause much confusion. It is possible to use an ordinary butt hinge but most hood doors have a special hinge type. Because of the way the hood door opens, the pin-line is usually set forward of the front face of the door. Flat brass or steel plates are cut to shape and fixed to the door.

Usually, the pin-line of the hinge is to the right of the right-hand edge of the door. In a design compromise, the pin-line in our hood is forward and slightly inside the right-hand edge in order to keep the pin away from the mitred joint of the hood-base moulding. A screw or nail driven into a glued joint is likely to create an incipient crack in the joint, which is likely to show up eventually.

A paper template will check the location of the pin against the glued joints in the hood base and pediment.

The hinge plates are cut from thin brass or steel plate and screwed to the top and bottom of the right-hand door stile.

A design compromise. The pin-line should be to the left of the edge of the door but that leaves it very close to the mitred joint in the moulding.

The hinge plate screwed in place, with one screw in the frame and the other in the baluster.

The pin-line is well away from the mitred joint and the door will swing freely.

Step 5 The Trunk Door

The design of the trunk door of our project clock is taken directly from the clock that we know to be of similar age and status. Our objective is to achieve the same overall proportions within the case and general appearance as in the door of the Benjamin Shuckforth case we are copying.

The door is made up from a single piece of wood shaped to fit into the frame, leaving an overlapping dust seal on the outside.

The wood chosen is sweet chestnut, a well-figured native timber that is reasonably stable and works well. The design requires the door to be made up in one piece; it fits partly into the door opening but is provided with a flange that closes over the outward face of the opening, to form the dust barrier. The edge of the door is shaped so that the rebate is cut to allow the door to close into the opening, and on the front an ovolo moulding is cut into the edge to relieve the otherwise heavy look of the square timber.

The door blank is 17mm wider and longer than the door opening and the flange should overlap on to the front face by about 8mm. The inside rebate was cut first to a depth of about 10mm, the thickness of the oak front panel that is made up of the door stiles and cross-rails.

A cutting gauge is used to make knife cuts parallel to an edge. It is the first tool that is used in making the ovolo moulding of the door flange. A cutting gauge looks at first sight to be so simple that it could not possibly work, but with a very sharp blade the results surprise those woodworkers who are more used to power tools.

Instead of the round pointed pin in a marking gauge, a cutting gauge uses a small flat knife blade to cut deeper into the wood. Cutting gauges are hard to find but easy to make.

The cutter, which protrudes about 1/8in (3mm), must be kept sharp or it will tear the wood surface.

The gauge is easy to use but it is a good idea to practise on a piece of scrap wood; once the blade is honed to razor-sharp, the depth of cut (1.5mm for our case) is set using a simple wooden wedge. The gauge is drawn along the edge of the work, keeping it square and true. It should run easily and square to the edge.

A sharp rebate plane might just be easier and faster than a modern electric router.

One alternative to the traditional wooden rebate plane is a steel equivalent (this one is a Record Number 78). They are probably better for softwood but they have the advantage that they can be used in either direction.

Once the cut is scored, the rebate is cut away using a sharp rebate plane.

When cutting the top and bottom ends of the door it is prudent to avoid letting the rebate plane cut all the way to the edge in case it drags splinters off the edge. To prevent that, the corner can be cut down with a paring chisel.

The blade is usually slightly wider than the sole of the plane, so it should be aligned carefully to keep the cut clean and straight.

Cut the outsides down to the line, working towards the middle.

With the top and bottom profiles cut, run the rebate plane down the long sides to leave a sharp corner.

With care, the rebate will be let into the edge of the door with clean sharp angles.

Check that the door fits properly into the opening and then turn it over to mark out and cut the ovolo moulding on the front of the flange. Use the cutting gauge again to set out the width, cutting down to about 1.5mm depth. A cut is made with the rebate plane down to that depth and the convex curved surface of the moulding is formed by taking several cuts with a paring chisel.

Rough out the ovolo profile with a paring chisel. It is a good idea to practise on a piece of scrap first.

It is possible to complete the curved profile with a paring gouge but sandpaper on a block is equally effective. Work all around the door edge, keeping the ovolo as even as possible. If you scrutinise that sort of detail in old country-made clocks, you will often find that the hand-cut mouldings are quite uneven, a feature that otherwise goes unremarked. The door is finished with progressively finer sandpapers, finishing at about 300-grit size.

The hinges in most longcase clock trunk doors are of a special type: the proper term is odd-leg finial butt hinges. They are odd-leg because one flap of the hinge is longer than the other. As on the hood door, the hinge pin-line is in front of the door to allow better opening and closing.

Mark the position of the hinges and cut away that part of the ovolo moulding. Attach the short leg of the hinge to the door edge.

To fit the door to the frame, first place a packer on the bottom cross-rail to ensure clearance for the door to swing.

An in-cannel gouge is useful but not vital; sandpaper on a block will give a neat finish.

Odd-leg hinges are almost always used in longcase trunk doors.

The blade of the screwdriver should exactly fit the slot of the screw.

A thin packer will give the necessary clearance for the bottom edge of the door.

Mark on to the frame the position of the hinges to indicate where the frame will have to be cut to recess the hinge flaps.

Cut out the hinge recesses, taking care to make a clean straight cut across the bottom of the recess. Use a sharp chisel to ensure that the wood is not ‘dragged out’.

Brass hinges are usually supplied with brass screws. For the unwary, small brass screws are quite fragile and liable to shear off in the wood. Whereas the short legs are screwed to the sweet chestnut of the door, the long legs will be screwed to much harder oak so it is prudent to run a steel screw of the same size into the pilot hole first.

Mark lightly with a sharp pencil.

Work away from the front edge.

Brass screws are prone to shearing off inside the hole, so pre-drill the hole and then use a steel screw of the same size to cut the thread.

Keep checking that everything will assemble properly.

Fix the hinges to the frame and check that the door swings and closes correctly.

When the door is satisfactory, the lock and escutcheon may be attached. Select an appropriate lock, which might be found on some piece of scrap furniture. Small single-lever locks of this type are readily available and it is not difficult to adapt a new key to suit. Mark out and cut the recess for the lock and mark the location of the pin so that the keyhole may be cut through the door.

The escutcheon protects the edges of the key hole and is a little embellishment. We found an appropriate model for our new escutcheon in an early eighteenth-century clock case in our workshop. It was a simple shape, in keeping with the almost puritanical style of our clock, in contrast to the more complicated and decorative escutcheons that became popular after the mid-eighteenth century.

A small steel lock will stay in place better if it fits neatly.

A pattern for the brass lock escutcheon on the door of an early eighteenth-century clock case. The shape is copied on to paper glued to a piece of brass.

Glue a piece of card on to the 1mm thick brass blank and mark out a copy. Cut around the pattern with a piercing saw.

The escutcheon is drilled for the fixing screws and then finished with emery paper ready for polishing.

The escutcheon is attached to the door only after the case has been coloured and polished.

Keep the work close to the jaws of the vice to stop the vibration.

Relieve the sharp edges with a file and then finish with metal polish.

Simple and unobtrusive would be in keeping with the rest of the case.

COLOURING AND FINISHING

We have no way of knowing whether the maker of the Benjamin Shuckforth clock case applied any colour to the new oak case he had made. It is well known that oak (like most woods) darkens gradually over the years, but the process can be accelerated in order to create an aged look. The darkening effects of a solution of the oxidizing agent potassium permanganate on oak have been known for centuries; indeed, the makers of fake Jacobean furniture are known to have made use of it for many years.

Potassium permanganate salt is dissolved in water at a rate of 25 grams to 1 litre. Care must be taken to avoid contact with skin and, as with any chemical treatment, the instructions and warnings must be carefully read and understood.

We opted to darken our case more because the fresh look of the new wood was somewhat obtrusive and not in keeping with the clock.

Having prepared a sample of wainscot oak and tested it for reaction to potassium permanganate solution and a couple of different chemical wood dyes, we decided to treat the clock case with the potassium permanganate solution, with the option of applying a further dye if necessary.

The case was left to dry out for a couple of days and the surface was rubbed over with fine wire wool and boiled linseed, because the water in the potassium permangate solution raises the grain from the wood surface, making it rough and impossible to polish. The linseed oil was allowed to soak into the wood for a couple more days. Finally, the surface was rubbed over with shellac polish to seal it, before burnishing with a beeswax polish.

Potassium permanganate solution (front) gives a more natural colour than the two synthetic wood dyes.

Apart from finding authentic old glass for the hood door and the apertures in the hood side panels, the burnishing finished our work on the case. Because we are professional restorers, we were obliged to mark the case so that it could not, at some time in the future, be passed off as the original case of the Peter Bower clock.

Native hardwoods should have a soft lustre and not a bright shine; the finishing process should reveal the figure in the woods.

Finished in the workshop, ready for glazing with some salvaged Georgian sash windows with the right sort of blown glass.

The overhauled clock movement is fitted into the new case ready for return to the client.

There are infinite approaches to restoration and conservation. This project was one involving restoration, because the clock was restored to a previous state rather than preserving what was left.

The dial exactly fits in to the bezel.

A small but important detail: Georgian glass is The overhauled clock movement is fitted into the new uneven and gives a distorted reflection. Modern float case ready for return to the client. glass is noticeably flat.

Chapter 5

A Clock-Case Restoration

This chapter describes the restoration of a severely damaged clock case. It does not cover all the faults that a conservator might encounter – one of the features of restoration and conservation is that every new day brings new unknowns and new challenges.

THE CLOCK

In November 2013, an eighteenth-century Dutch longcase clock was sold in an auction in Essex, UK. It had been seriously damaged in a fire and the successful Irish bidder commissioned us to undertake a complete restoration, with the objective of returning the clock to a condition more or less as could have been expected before the disastrous fire.

The description in the auction catalogue was quite detailed:

The following four lots are fire damaged. The cases are significantly burnt, the veneer will need replacing and the movements are smoke damaged. A Dutch longcase clock, 18th century, by Johannes Pieter Kroese, Amsterdam, the arched brass dial with a moon phase over a silvered chapter ring containing a seconds dial, day, month and date apertures and scrolled appliqué engraved ‘Pieter Kroese, Amsterdam’, the eight-day five-pillar movement with passing quarter striking on two bells, dial 12¼in, 31cm case 232cm high.

The auctioneer’s condition report also recorded that the clock was ‘complete with pendulum and two weights’.

Our research usually starts with Brian Loomes’s Watchmakers and Clockmakers of the World, Complete 21st Century Edition, which contains a brief entry for Pieter Kroese:

Kroese Pieter, Amsterdam, son of J P Kroese qv c 1770–late 18th century.

Pieter is known to have worked at the same workshop as his father Johannes Pieter, in Kalverstraat, near the centre of Amsterdam. The tradition of clockmaking in Holland dated back to the Middle Ages. The Dutch were expert mariners and in the early seventeenth century substantial wealth was generated by the Dutch East India Company. Although there is some debate about whether it was the Dutch scientist Christiaan Huygens or the Italian Galileo Galilei who discovered the isochronous behaviour of the pendulum, it seems clear that it was the former who developed the idea, and it was a clockmaker in The Hague in 1656 who first made a pendulum clock.

Our project longcase clock was made a little over one hundred years later, by which time the Dutch longcase clock had evolved a recognizably different style to its English counterpart.

The clock is a very fine example of the excellence of eighteenth-century Amsterdam clock-making; in addition to hours, minutes and seconds, it also indicates date, day of the week, month, phase of the moon and high water at Amsterdam. In keeping with the prevailing style of Dutch longcase clocks of the mid-eighteenth century, the burr walnut case is ornamented with marquetry and gilded highlights. The movement is recognizably Dutch rather than English and strikes the hours and quarters on two bells (Dutch double-strike) with a repeat and strike or no-strike option.

The Dutch double-strike is more properly called the Dutch two-bell, quarter-strike system. On the hour it strikes the number of the hour on the large bell and then, at the first quarter, one strike on the small bell. At the half-hour it strikes the number of the coming hour on the small bell and at the third quarter it strikes once on the large bell.

In a sorry state – the fire damage had destroyed some of the veneers and mouldings, especially higher up the case where the heat was concentrated. It was probably the rescue from the fire that caused the serious structural damage to the case.

Although it was marked by the fire and had sustained some permanent damage to the painted surfaces, there are a few features that alerted the buyer to the unusual quality of the clock. It is unusual to find a Dutch clock of this period with two segments in the dial (day of week and month): the small aperture to the left of 3 o’clock is for a strike/no strike lever and the small aperture above the moon phase is an indication for the time of high tide at the place where the clock was intended to reside. It is correct in local time for Amsterdam.

The original of this complicated striking system is unclear but Thomas Tompion had made his No. 145 with an English variant of the Dutch double-strike before 1690. Its presence in the Pieter Kroese clock is further evidence that it was a high-status object and would have been extremely expensive to buy in the late 1760s.

The fragile condition of the damaged clock was not improved when the auctioneer mixed up the lot numbers and the clock was mistakenly shipped to Amsterdam instead of Dublin. The buyer was notified about the mix-up and eventually the clock was delivered to our workshop for restoration.

PREPARING FOR THE RESTORATION

We use the word ‘restoration’ rather than conservation in connection with our work on this clock case because we were required to restore the appearance and function of the clock to the way it was before the fire damage. The word ‘conservation’ applied in its correct sense would imply preserving the fire-damaged clock with no attempted reversal to a former state.

For our guidelines on the restoration and conservation of horological objects, see Appendix.

The arrival of the clock coincided with the commencement of a three-month internship for two restoration/conservation undergraduates from the Finnish University of Applied Science and they were assigned to work on the restoration programme, under strict supervision. Third-year restoration students mostly have a good grounding in the theory and principles of restoration and conservation but they benefit immensely from practical experience with real projects. Although they are naturally inexperienced in hand-craft work, they can sometimes have a misplaced confidence in their ability. Consequently, they must be very closely guided.

When the clock was unpacked, several things became obvious. First, it was in an even more fragile state than we had anticipated. Second, there was an unusual feature in its construction: the case had been made as three separate and detachable units – the base, trunk, and hood frame and removable hood sub-assembly. The base, trunk and hood frame (on to which the hood slides) were each fixed together with pairs of sliding mortise and tenon joints secured with removable pegs.

Because of this type of construction, the restoration project was broken down into several modules and the movement was restored separately.

The Condition Report

Before any restoration work can commence, the object must be thoroughly researched, examined and described in photographs, sketches and notes. The actual dimensions, materials, damage, deterioration and any other information are recorded along with the relevant historical research. Photographs are useful but sketches are preferred because they can highlight certain details. All of this information is compiled into the Condition Report.

The Condition Report provides the basis for decisions about how the restoration work will be done. Naturally there will be a wide range of options for restoration, each with its own outcomes and budget. The role of the restorer or conservator is to set out the facts and options to the owner or guardian.

The most frequent cause for disagreement and debate in clock restoration and conservation is the conflict between allowing a clock to continue ticking, and hence wear its parts, and the over-riding principle of preservation, which seeks to prevent further deterioration and conserve the clock indefinitely.

The arguments against letting a clock continue to run are about the controlled and meticulous preservation of an object of cultural heritage in as intact a condition as possible, with a minimum of intervention. Those in favour of allowing a clock to run cite the sound and movement of a clock as an essential part of its integrity. In other words, they believe that it is the sound and movement that should be preserved

Each part of the clock was measured, described and photographed. Even the parts that were damaged beyond use were recorded.

Surface finishes and decoration were photographed, measured and described.

Physical dimensions and features were recorded as a basis for the Condition Report and to record the restoration work.

The Condition Report drawings are somewhat stylized but they highlight the areas for consideration in the restoration plan. It is not for the restorer to decide on a plan of action; his role is to inform the owner or guardian, who then makes the decisions.

The restoration and conservation of cultural heritage is full of conflicts and differences of opinion, but it always remains the prerogative of the owner or guardian to make the final decisions, based on his own judgement and enlightenment offered by the restorer or conservator.

The Condition Report, with its drawings, photographs and text, should be kept with an object for reference by future owners in case further work becomes necessary.

The Restoration Plan

As a matter of procedure the restorer or conservator should formulate a plan about how the restoration work will proceed and how that work is intended to preserve the heritage object. The pros and cons of various approaches are assessed. Again, budget is a factor, but the objective of a restoration plan is to reach unambiguous agreement with the owner or guardian about how to carry out the work and how the work will be monitored and recorded. A restoration or conservation plan cannot foresee the unexpected but it can make provision for alterations in the programme of work as new information comes to light during the work. That implies a need for good communication with the owner or guardian.

THE RESTORATION WORK

With all the agreements and procedures in place, the work can commence, always bearing in mind the Code of Conduct of the Institute of Conservator Restorers in Ireland: ‘Any action of the conservator-restorer must be governed by a respect for the aesthetic, cultural, historical, and physical integrity of the object.’ The spirit of that tenet does not come naturally to a beginner but gradually it is indelibly imprinted into a conservator’s thoughts so that it governs all of his work.

Restoration of the Base Section

Primarily, the work on the base section involves the removing of scorched shellac, the application of a new polish and re-gilding of the feet.

Apart from a few loose or missing mouldings, the base of the Dutch clock was intact and the fire damage seemed to be less severe nearer to floor level. The veneers were still firmly attached but the shellac had deteriorated. Solubility testing a small area with ethanol on a swab (ordinary methylated spirit or alcohol on a cotton bud) confirmed that, as expected, the damaged finish was shellac. (Where ordinary grime discolours the swab, dissolved shellac leaves it sticky.)

The scorched shellac polish was removed from the surface of the wood veneers by covering areas with a poultice of absorbent paper towel soaked in alcohol and after a few tens of minutes wiping off the softened debris. The poultice should be covered with polythene sheet to minimize evaporation of alcohol into the working environment.

The yellowish-grey opaque surface deposit is heat-damaged shellac. Shellac and animal collagen glues both melt at quite low temperatures so, if there has been enough heat to melt the shellac, it is possible that the veneering glues also melted.

An early glimpse of the burr walnut veneers as the first alcohol poultice is removed.

The potentially fragile marquetry inlays required careful cleaning.

With all of the old polish removed, the affected areas were scrubbed lightly with boiled linseed on very fine wire wool, which lifted any remaining debris. New shellac polish was applied to the base panels and mouldings prior to cleaning the two lion’s-paw feet.

The same marquetry inlay, all intact. The cleaned surface is wiped with boiled linseed oil to prepare it for re-polishing with new shellac.

The front and canted corner panels of the base with their original burr walnut veneers, embellished with a neo-classical leaf and scroll marquetry design. It is not unusual for the side panels to be finished in a plainer, straight-grained veneer.

One of the recurring themes in restoration and conservation relates to how much or how little to do. After the first priority of achieving stability, it was necessary to consider the most appropriate treatment for the lion’s-paw feet. The Condition Report had noted the presence of traces of gold leaf on a green undercoat, which testing had shown was not a conventional gilder’s bole. (Bole is a mixture of clay and rabbit-skin glue that can be rubbed to a very smooth finish. It softens in hand-hot water.)

In order to preserve the aesthetic integrity of the original, the restoration plan called for the reinstatement of an impression of gilding without making it look obtrusive.

An underlying colour is usually visible in worn gilded work; in English furniture and clocks, a red or orange bole would be the rule but in Continental Europe green is more common.

The feet were cleaned and coated with a paste watercolour paint that matched, as far as we could tell, the original undercoat. After smoothing with fine wire wool, a 23.5-carat gold leaf was applied using an oil size.

Behind the encrusted deposits of shellac and other debris, there were small traces of a green surface on to which gold leaf had been applied.

Viridian Green watercolour paint applied in its paste form direct from the tube.

Gold leaf applied to an oil size. The somewhat obtrusive effect was likely to over-power the composition of the whole clock.

The gilded feet were rubbed back to reveal the ground in patches. The result was an impression of the foot having been gilded and now being somewhat distressed.

Gold leaf rubbed back to leave the impression of gilding with the new look.

Defining the ‘integrity’ of an object often calls for judgement to be applied, and choices that are more cosmetic than structural need not be the basis for complicated arguments about applying the principles of conservation, as long as the cosmetic finish can be reversed with no long-term damage.

Restoration of the Trunk

This part of the restoration dealt with the broken backboard, loose veneers, loose and broken sliding tenons, veneers damaged beyond repair and other general fire damage.

Repairing the Backboard

When the trunk section was removed from its packaging it was in several parts: the two side panels, the front section including the door, and the backboard, which was itself broken into two pieces by a split down the grain.

In order to be able to rebuild the solid structure of the trunk, the oak backboard was the first component that needed to be rectified. In almost all longcase clock cases it is the foundation of the structure and without a structurally sound backboard the rest of the clock case is fragile. The break in the backboard, which divided it into roughly two halves, was surprisingly fresh and unscorched, from which we concluded that it had occurred after the initial fire damage.

The extent of the damage to the trunk. The backboard is broken from the side panels but not entirely at the glued joint.

Likewise, there were fresh and unscorched breaks at the outer edges of the backboard, with remnants of the backboard attached to the side panels of the trunk.

The backboard parts were glued back together and then, to reinforce the joint, three dovetail ties were let into the back surface. Dovetail ties are the traditional way of holding a rubbing joint together. They work well when they fit tightly but it is essential that the tie is cut first and that the grain-line of the tie is arranged to be across the joint. Using the tie as a template, the boards are scribed with a fine scalpel blade and the scribed cut is then deepened and developed into a Vee cut around the inside on the area to be removed. Very sharp chisels will be required and, in order to cut cleanly into the acute angled corners, skewed dovetail chisels are preferable. (You can make skew chisels out of any spare ½-inch chisels but they must be ground slowly to avoid overheating, which would lose the hard temper of the edge.)

Cross-section through the trunk showing the construction of the components and the arrangement of the pegged sliding tenon that secures the trunk to the base section. There is a similar sliding tenon arrangement to secure the hood frame to the top of the trunk. The case-maker has used thick vertical members for the front panel, to accommodate the canted front corners.

The badly broken back-board, with a second fracture visible. It was flexed open to insert glue while the two major parts were being glued up.

The cutting tools that are needed to let the dovetail tie into the back-board: 1-inch and ½-inch paring chisels and left- and right-handed dovetail chisels.

Scribe around the dovetail tie and then open up on the inside of the scribe with a Vee cut.

The outside face of the back-board, showing the dovetail ties. The two lower ties straddle the second fracture, uniting the entire back-board. The ragged outside edges are visible.

Re-Assembling the Trunk

With the backboard stable, the side panels were attached, taking care to keep the correct separation for the front panel. Frames were made up to hold the assembly square and provide a reaction member for the clamps.

In common with the majority of veneered clock cases of the mid-eighteenth century period, the side panels were plainer, made from walnut stem wood. A badly burned section of veneer at the top of one of the side panels was stabilized and left without patching. The conservation principle was to minimize intervention, and preserve evidence of the fire that promoted restoration of the case. The justification for leaving that part unrestored exemplifies the ‘least intervention’ approach to restoration:

•  The affected area is at the side of the clock case and not immediately obvious so it does not compromise the aesthetic integrity.

•  It does not compromise the long-term stability.

•  Even if a veneer patch could be blended to the original, there should be no attempt to disguise the effects of the fire damage.

In order to fit the front frame, the door was removed from the front panel to facilitate its restoration as a separate unit. The front frame was then re-glued into the trunk. The veneered, canted front corners are a special feature of the case and great care was taken to preserve the veneers. Inevitably a few small patches were required to prevent an otherwise obtrusive appearance.

The side panels of the trunk ready for re-attaching to the back-board.

The side panels are glued to the back-board. The frames ensure that the gap between the front edges of the side panels will give an interference fit for the front panel, which must fit between them. On the right, the mortise blocks with their square-headed pegs are the fixings for the hood-frame tenons.

Seen from the back, the side panels are fitted back to their original locations.

Any old furniture or clock case carries a legacy of historical repair work and there was some evidence that the internal faces of the backboard to side panel joints had been reinforced with glue blocks and metal brackets. We had no way of knowing whether glue blocks were part of the original construction or not, but, in view of the scale of the re-building work, we opted to insert a series of glue blocks at those joints.

The left-hand side of the trunk below the hood frame: the veneered canted corner has been reinstated. There is evidence of an impact to the top of the side panel, with a loss of scorched and deformed veneer.

Oak is notoriously unwilling to accept glue and old dirty oak is unlikely to be any more amenable. To ensure a strong bond, the gluing surfaces were scraped to expose fresh wood and then moistened to raise the grain, which allows the glue to bond more readily to the wood fibres. It is important to apply pressure to any glued joint and this can be problematic on the inside of a clock case. The easiest procedure is to use a flexible sprag (a load-bearing prop in the style of a mine roof support). The sprag is flexed against the glue block, with the other end held in the opposite corner of the case.

The method of applying pressure to internal glue blocks using diagonal sprags.

One of several 17 × 17mm glue blocks that stiffen the back-board joint. Also visible is the new sliding tenon pegged into the mortise block of the base section.

The Sliding Tenons

It is not clear why the case was made in three demountable sections. This unusual construction was probably for ease of transport but obviously we also attach importance to the presence of the sliding tenon construction. Of the two sliding tenons that fix the trunk to the base section, one was loose but the other had cracked across the screw holes and was replaced with a new part.

The Trunk Door

At first sight it seemed that the door was in a very poor state and unlikely to survive. It was recorded in minute detail against the eventuality that it would have to be replaced, then we proceeded with restoration work.

Stability is the first priority in the restoration or conservation of any fragile artefact and the three features of most concern on the Dutch clock were the following:

•  the unstable marquetry;

•  the loose and damaged dust bead that was overhanging the front face to cover the gap between door and frame; and

•  the large areas of loose veneers.

A broken sliding tenon (43 × 8 × 95mm). Stability over-rides retention in this case because the tenon had been snapped off, either during rescue from the fire or during transit. A replacement was made up from similar European oak. Whether it is restoration or conservation, as a matter of policy, stability of the whole over-rides the preservation of a part.

The door still in the front panel of the trunk. The fire damage is concentrated at top left but all the veneers are disturbed.

Loose sections of trunk-door dust bead glued back on the veneer surface prior to applying heat and pressure to re-glue the veneers.

We concluded that the heat from the fire had been sufficiently intense and prolonged to melt the glue so that the veneers and marquetry had lifted unevenly from the flat oak ground. We opted to attempt first to save the veneers by applying heat and pressure to re-melt the glue and press the veneers back on to the ground. We did not to attempt to clean the charred shellac until we had attempted to re-glue the veneers because of the perceived risk of inadvertently transferring cleaning debris contamination through fractures in the veneers into the voids between the veneers and the solid ground of the door panel.

With the dust beads secured and replaced as needed, the veneers were pressed down by first heating with a medium to high temperature flat-iron, and then by applying firm hand pressure through a flat wood block until the re-mobilized glue set. This is always a slow process, made possible only because the glued surfaces had been freshly separated and were not contaminated.

Carved flower and ribbon bow ornament on the top of the door. Precariously loose marquetry veneers are more pronounced at the top of the door than at the bottom.

Marquetry tends to become unstable when individual pieces become dislodged and the few missing parts were cut from box-wood salvaged from an old chisel handle.

Early longcase clocks often have a lenticle or small window in the door, through which the pendulum is visible. The Dutch clock was fitted with a peculiarly Dutch brass bezel that secured the lenticle glass. It is not a unique design and the identical brass lenticle bezel was fitted to Dutch clocks in the mid-eighteenth century. From the discoloration on the surface, it had apparently been coated with a lacquer to inhibit tarnishing. It was removed for separate cleaning and re-lacquering prior to the work of reattaching the door veneers.

The cast-brass lenticle bezel in a design that is often seen in mid-eighteenth-century Dutch clocks.

The bottom of the trunk door. Veneers have been successfully re-glued and burnt shellac has been removed from a small test area by dabbing with alcohol on a swab.

A more widespread application of liquid alcohol softens and dissolves the burnt shellac almost immediately.

The marquetry ornament appears to be relatively undamaged.

A final wipe with boiled linseed and the door is ready for polishing.

Push the shellac polish on to the work with a padded cotton rubber that is only slightly moistened with polish. The polish will build up gradually as long as it is not applied too wet.

The effect of shellac polish should look like burnished wood, not a thickly applied varnish. If the shellac is rubbed back occasionally during polishing, it will keep the thickness of the polish to a minimum.

Masking tape protects the freshly shellac-polished surfaces. A red bole was used here; where the hollows in the carving are awkward, persistence is needed to get a cover of gold leaf.

Any repaired veneered surface should be checked carefully before applying shellac polish because, if there are any voids, they will only get worse. The preferred method is to tap all over the surface lightly with the fingernails or the edge of a steel paint knife and listen for the characteristic hollow sound that indicates a void.

The carved ornament was cleaned of burnt shellac and re-gilded over a red bole.

The Hood Frame

The hood frame was designed to be attached to the trunk assembly by two sliding tenons in the same manner as the fixture of the trunk to base section. We do not know of any other clock case constructed with a hood sub-frame in this modular way and, although it appears to have been made to be easily portable, the presence of the high-water indication on the dial suggests a fixed abode. (We only assume that the high-tide indication was set for Amsterdam because at full moon the clock indicates high water at 3 o’clock. Modern tide tables agree when converted to solar time but it would also be correct in certain other geographical locations.)

The hood frame showing a combination of fire damage, impact damage and a legacy of historical repairs.

The front moulding section, complete with part of the left-hand up-stand, which supports the seat-board. Sections of burr walnut veneer are missing from the top (vertical) surface.

Replacement hood-frame moulding, cut using simple hand tools by an inexperienced restoration student. When finished, this oak core was veneered in walnut stem wood to match the opposite moulding.

The historical repair work that joined the two parts of the hood-frame back-board was removed and the badly charred straight edges removed to glue in a new section.

The hood frame had arrived in two large parts, with several loose fragments. It was rebuilt using as much of the original as possible. The backboard section was in two parts, which had apparently been joined during some historical repair work by two crude cross ties. The previous mend was removed, straight edges were cut on the edges of the original pieces and a new piece of similar oak was inserted. A replacement for the missing left-hand side trunk moulding was made up in oak to match the opposite side.

The completed hood frame has been made structurally sound with the minimum of intervention.

The Hood

The hood presented by far the greatest challenge, not just in the work that was required but also in the interpretation and application of the principles of good restoration.

It was quite clear from the degree of damage that the heat from the fire had been concentrated at the hood; veneers were burned beyond repair or missing, the fretwork was damaged and broken, some of the mouldings were missing and some of those remaining were charred to the point at which much detail was lost. However, we established that, apart from the top section of the hood, which was absent, there remained sufficient material at least to use as templates for new parts.

The hood is constructed from a base frame that slides on to the hood frame of the case. The two side panels and the front door frame are united by the break-arch pediment. The whole construction was then embellished with burr walnut veneers to the front and mouldings were applied to the bottom frame, above the arch and to the pediment. Pillars were applied to each side of the hood door, with mitred capitals fixed to the tops and bases of each pillar. The use of ornamental pillars or balusters fixed to the door seems to have persisted longer in Holland than elsewhere. By the second half of the eighteenth century in the British Isles longcase clocks were being made with free-standing hood balusters.

The hood-door half-pillars (pillars are square in section, columns are round) have attached capitals at the tops and bases. The front pillars are repeated at the back of the side panels with quarter pillars of the same design. Various segments were missing and copies of the two profiles (top and bottom) were made up to match using chisels and gouges.

Visitors to our workshop often ask where we get the router bits for such one-off moulding profiles and the answer is, of course, that these profiles are all cut by hand by following a section of the original. The students learn quite quickly that it is impossible to find off-the-shelf parts for two hundred and fifty-year-old clock cases. Every replacement part must be crafted by hand.

The hood with widespread losses and severe fire damage. The remnant of moulding over the arch was reduced to a charcoal-like texture but it was still possible to measure for a replacement. Despite the appearance, the frame, side panels, pediment and door were useable and there was enough left to complete the conservation.

The hopelessly damaged fretwork panels viewed from the side. They were backed with a thin fabric – we were not convinced that these were the originals and, in any case, they needed to be replaced.

The circular moulding over the arch was made up on a lathe face-plate. The moulding sections were all mitred together so that the details of the profile aligned correctly.

Replacement parts, the arched section of the bezel, the circular moulding and the new pediment veneers, which have been cut to the profile of the surviving crest moulding.

The hood door was re-veneered and replacement parts carved for the missing capitals and bases of the pillars. In keeping with common practice in clocks of this sort, they were gilded.

Simple moulding section for the hood-door pillars cut by hand with simple tools.

Re-gilding the capitals and bases of the restored and re-veneered hood door.

Restoration of the Carving

For the beginner, wood-carving can seem to be an impossibly difficult task but, over the years, different students have successfully taken on the challenge of making up replacement carved parts for a variety of antique objects.

The hood crest carving. The upper section had been burned away but it was possible to assume that the ribbon bow in the trunk door carving was repeated here. The asymmetric design suggests the rococo influence, which spread to the British Isles in the 1770s. Traces of gold leaf were apparent.

The ribbon bow reinstated. After a few practices in lime wood, a block of fresh walnut was glued to the top of the remnant carving, and the bow carved into it. A red bole was applied before gilding.

Because decoration is purely an artistic addition, it is important for the new restoration work to be in keeping with the original.

The carved detail on the top of our clock hood had lost the top section, which, based on a smaller version on the trunk door, we believe was originally an open ribbon bow.

There are no secrets to carving – it only takes practice. The student assigned to the work learned the hard way that modelling a mock-up in clay is not necessarily helpful. Clay modelling adds material to build up the solid form, but carving removes material. Eventually, after a few attempts, a passable result was achieved.

Re-Veneering

The trunk door gave us a good model for the style of burr walnut veneers, which we found on the case of a scrapped early-twentiethcentury upright piano.

Veneer thickness is a consideration because modern veneers are much thinner than the eighteenth-century sawn equivalents. From the remnants of veneer on the hood that we could measure, we estimated the thickness to be roughly 1.5mm, almost twice the thickness of modern machine-cut veneer. We took 1.5mm slices off the piano panels so that we could join new with original without a palpable step. Leaving a thin layer of the ground wood on the salvaged veneers keeps them stable and makes them much easier to handle and lay.

It is possible to buy new burr walnut veneers but salvage is better because it is easier to match for colour and figure when it has been cleaned and polished. Every part of a piano case, regardless of size, is carefully stripped of its veneer.

Debris and old glue was removed from the hood parts using a domestic steam-cleaning machine. Laying new veneers on to previously veneered surfaces is not easy; mostly, old wood surfaces were scored with a toothing plane and the roughened surface tends to hold residual glue. To give the assurance that the new veneers will be fixed soundly on to wood fibres rather than on to old and dirty glue surfaces, it must be thoroughly scoured. The procedure for laying veneers is described in detail elsewhere.

Steam is potentially harmful to wood but it can be the best option for removing old animal collagen glues and dirt. It is also useful for removing veneers.

A sharp, thin-bladed knife is used to cut thin veneers. Craft shops sell scalpels but we prefer a home-made knife made from an old hacksaw blade.

The work gets easier once some progress has been made.

Restoration of Four Fretwork Panels in the Hood

After careful examination we concluded, on the basis of materials used and the design, that the two larger pieces in the side panels were replacements and that the two smaller panels in the pediment were original. However, they were all made from composite wood laminate material.

There was almost enough of the top frieze left to design a replacement. A trace of the missing part appeared on the smoke stain on the silk fabric.

Condition Report drawings are easier to interpret than photographs.

Following the original as far as possible, a template is made up for the replacement fretwork.

The coping saw on the left is far too heavy for fine work. A piercing saw or jeweller’s saw fitted with spiral cut blades will cut accurately but it is still advisable to temporarily fix extra sheets of veneer to the work to prevent rag and splinters.

In any event, all of the fretwork panels were beyond repair so we set out a design and made up blanks from which to cut replacement panels.

Gluing thin sheets of wood together with their grains running crosswise was a relatively new technique in the mid to late-eighteenth century. Although composite laminates (equivalent to modern plywoods) are known in eighteenth-century French furniture and in the glazing bars of English Georgian bookcase doors, a patent describing the manufacture of plywood was only granted in 1797. The design was transferred to a composite blank made up from five sheets of mahogany veneer, glued with water-based resin glue and cured in a heated book press. Cutting out is best done with a jeweller’s saw, using a spiral or twist type of blade that will cut at any angle.

The new panels are glued into the hood.

Careful planning, setting out and preparation of the blank results in acceptably good fretwork panels. Conservation students are sometimes surprised that they have to learn these sorts of skills as a new aspect of restoration.

The outcome of our conservation programme is as sympathetic to the original as we could achieve. We have tried not to introduce anything about which we were not sure.

The finished clock case, with its restored movement and dial fitted. As restorers and conservators, our responsibility to the clock does not stop there. We also provide advice to the owner about keeping the item safe and secure so that it might be handed on to subsequent generations.

The clock movement has been restored to a good condition.

The clock case has lost little of its presumed former appearance.

The woodwork repairs to the back-board have not been coloured to mask the work, which has now become part of the clock’s legacy.

We have not achieved a miracle but what we have done is to work systematically through the project, from the initial unpacking, recording and preparation to the Condition Report, via all the questions and alternatives presented in our restoration plan, to the finished restored clock.

The outcome is the result of research, judgement, experience, guesswork and compromise, and all the work was documented for the benefit of future guardians and restorers. There is no upper limit to expertise and the next clock-case restoration project will undoubtedly entail a different set of challenges in uncharted territory.

Chapter 6

Some Wooden Clock Cases and Their Restorations

There seems to be an almost infinite variety of wooden clock cases but, actually, if they are not longcase clocks, almost all of them fall into one of two main categories:

•  Type 1 cases have an ornamental front with a box-like structure behind to house the clock. All access into the case is from the front and the backboard is solid.

•  Type 2 cases are solid wood constructions with all access to the clock movement through a rear door.

Type 1 cases can be either wall-hanging or shelf (mantle) clocks but Type 2 cases are almost always shelf clocks.

EXAMPLES OF TYPE 1 CASES WITH SOME TYPICAL FAULTS AND REMEDIES

English Single Fusée Wall Clocks of the Mid-1800s to 1914

Also known as the railway clock or school clock, this type of peculiarly English clock is an anachronistic extension of the use of the fusée, which had been shown to be unnecessary by the American and European clock trades. Restorers should be aware that the German company Winterhalder & Hoffmeier made thousands of similar movements for export and, more recently, twentieth-century copies have also been produced, often stamped ‘6472 LONDON’.

The dial is fixed into a solid turned hardwood bezel and the movement is fixed to the steel dial by three dial feet. The dial is secured to the case proper (that is, the box behind the dial) by four tapered wooden pegs.

An English single fusée clock of c.1900. The winding hole just below centre indicates the presence of a fusée; the 12-inch steel dial is screwed to the turned mahogany bezel.

In the clock illustrated, the pine backboard is rebated into the half-inch mahogany sides of the box and a veneered pine curved lower section that encloses the short pendulum. Two doors are fitted, one at the right-hand side and a curved one in the underside (for access to the pendulum-regulating nut).

The most frequent and noticeable of the faults that affect this type of clock case is a curl that develops in the wooden bezel. The bezel is often turned from a single sheet of approximately 1-in mahogany so it is also prone to splitting on the short grain. A curl is often precipitated by a loosening of the framing that locates the box to the dial assembly and, since the back of the bezel is of unfinished wood, the ingress of moisture tends to curl the bezel to form a bow in the back and a complementary sag across the front. The remedy is to remove all traces of polish and then moisten the bezel and place between flat cauls to dry gradually – over a period of weeks rather than days.

The vertical framing pieces locate the box that houses the movement but, if they come loose, the bezel is liable to curl in adverse conditions of humidity.

Dovetail joints and precise detail in English fusée clocks usually suggest the work of an individual cabinet-maker rather than a factory production line.

All the railway companies used fusée clocks.

A long temperature-compensated pendulum fusée clock that is believed to be a former shop regulator in a watch and jewellery shop in Limerick, Ireland. The 14-inch (350mm) dial is for public display. Irwin Bros Jewellers was located at 22 Patrick Street, Limerick, until 2011.

A late nineteenth-century imported German single fusée movement is supported by four dial feet attached to the heavy steel-plate dial. The turned oak bezel is made up from four segments, arranged so that the wooden rails designed to locate the dial on to the case overlap three of the four joints.

A heavy oak case is constructed along the lines of English cabinet work rather than American clock cases.

Gadrooned ears are a concession to the late Victorian taste for the embellished. The case has been made far deeper than was necessary to house the clock.

The basic single fusée layout was adapted for use in larger clocks for commercial premises. The early railways in Great British had used local time but in 1847, because of mismatches in timetables, a national standard time system was introduced. It was initially called ‘Railway Time’ but later became known as ‘Greenwich Mean Time’. A parallel time-keeping development, the electric telegraph system, which was introduced in the 1840s, allowed synchronization of railway clocks. The railway clock with the company logo marked on its dial spread with the railway system across the country, bringing a new level of time-consciousness to the British population.

Fusée clocks were also used in shops and other public buildings, quite often with a longer pendulum housed in a drop below the dial.

American Ogee and Drop-Dial Wall Clocks

These types of clock were made from 1840 by new mass-production methods.

Ogee Clocks

Ogee clocks were one of the earlier successful designs for American high-volume clock production. The mass-produced movement is driven by weights, which require a certain vertical fall between re-winding. The characteristic ogee moulding (an ‘S’ shape in classical architecture) is both decorative and functional. It supports the door, which is recessed to facilitate stacking so that the clocks could be transported in large numbers. Thin veneers of exotic woods such as mahogany and rosewood were fixed to long sections of moulding prior to mitre-cutting for assembly.

A typical early American ogee clock from the Jerome Clock Company (which had ceased to exist by the early 1850s). Three different curved moulding profiles are used on the front of the clock: the larger, the ogee in this clock, is veneered in flame mahogany veneer; the outer convex facing and the concave door mouldings are veneered in rosewood.

A previous attempt at restoring lost veneers. The veneers conspicuously do not follow the hollow of the door moulding, so the intended effect is lost.

Apart from re-assembling loose structural components, the most significant restoration work in ogee clock cases relates to the veneers that are applied cross-wise to both convex and concave surfaces. A canvas bag filled with hot sand is the best way of applying pressure to veneers laid on the ogee moulding but the narrow concave surfaces of the door frame are better re-veneered by using specially made up round-faced cauls that exactly match the moulding, and then pressing the veneer into the hollow. In order for the veneer to sit into the curve of the moulding, it should be as thin as the originals. It may still need to be soaked in very hot water just before laying on a water-based adhesive or animal collagen glue.

As examples of the early development of clocks in America, ogees retain an interesting feature that was commonplace in much older English clock designs. The clock movement, instead of being screwed directly to the backboard, as it was in later American clocks, stands on a separate seat-board, which itself slides into two grooves in the upstanding plates that support the dial. The stability of the clock movement depends on how well the up-stands are fixed to the backboard. When an ogee has been hung with its backboard in contact with a damp wall for years, the nails are apt to rust and the glue will deteriorate. The resulting movement in the up-stands may stop the clock.

The seat-board arrangement in an ogee clock is designed to withstand the force of the driving weights.

American Drop-Dial Wall Clocks

Drop-dial clocks were made in huge numbers for export to Europe. The movement was a spring-driven development from the earlier weight-driven ogee movements. It is screwed to the solid backboard and the dial is supported by a wooden bezel, usually veneered and decorated with inlaid bands of contrasting woods. Drop-dial clocks were imported into Britain in large quantities and retailers would often mark their name and place of work on the dial.

Although the movements are surprisingly robust, the cases tend to suffer from the effects of a harsh domestic environment: airborne greases from cooking and tar from tobacco can accumulate on polished surfaces, obscuring the decorative effect of the variegated inlays.

A typically distressed American drop-dial clock. Missing ears and loose or missing veneers are often a result of storage in a damp atmosphere. The triangular dogtooth inlay band is difficult but not impossible to copy – off-the-shelf replacements may be the wrong style and size. Fallers Jewellers was established in 1879 in Galway and is still in business.

A restored drop-dial clock. The ears and the fretwork in the pendulum door are replacements as is the inlay band around the dial.

The Black Forest Wag on the Wall Clock

These quite familiar wall-hanging clocks were exported in huge numbers from the Black Forest area of Germany from the mid-nineteenth century, but give the impression of cottage industry rather than factory. The alternative name of ‘postman’s clock’ is an allusion to the alarm element. Because the movement is constructed along the lines of that of a medieval striking clock, with the strike (or alarm) train behind the going train, the box-shaped case is relatively deep. In common with English lantern clocks, the movement is supported within three wooden plates that are fixed to top and bottom boards.

The Black Forest alarm clock. Similar clocks are depicted in the illustrations in the mid-nineteenthcentury novels of Charles Dickens.

The doors are hinged on the back-board.

Somewhat crude but very effective.

The back of the clock, with the going train of wheels to the right and the alarm to the left.

The cases are not strictly Type 1 and the sides are typically of thin (3mm) sheets of pine with simple pin and loop hinges made from steel wire. The side doors tend to disappear, which renders the clock movement susceptible to airborne dust. For restoration, hard-drawn piano wire is a good material from which to make replacement hinges and catches.

Various Shelf Clocks, European and American

In the 1880s, the American clock trade developed a form of shelf clock that is now known as the ‘Gingerbread’ and almost all the major American clock companies produced versions of the type. There are two forms: the earlier, usually in walnut, with incised carved detailing, and a later, embossed oak type. The baroque embellished style fell out of favour with the advent of Art Deco fashions and restoration work is often related to abandonment and rediscovery by successive generations of owners of this type of clock. The construction is simplified for mass production, consisting of a box on a base-board with the ornamental front glued on in three sections.

Schematic layout of the major components of a ‘Gingerbread’ clock case. The ornamental front, which is made up in the three sections, is prone to damage by splitting along short grains.

A typical Gingerbread restoration project, with a few missing parts and extremely distressed from a long period in damp storage. The dull brown colour appears to be a mixture of grime and a tarry substance (cooking grease and/or tobacco tar).

The box sections are made up from a rebated profile and mitred together so that the back-board can be inserted flush.

The remnant of a label reading ‘ANSONIA’, still attached to the woodworm-infested back-board. Preserving labels is a good idea; buying new replacement labels is not really good conservation practice.

The door frame was also made up from lengths of special moulding mitred together, with the mitred joint reinforced with a flying tenon. It was an early form of what developed into the biscuit jointing system.

Cleaning with alcohol and linseed reveals that this ‘walnut’ is made from North American white oak. Rules always have exceptions and this type of hybrid is far from unique.

The finished restoration.

While the embossed oak cases represented the technical advance of powerful presses and dies, the earlier walnuts were embellished by hand-cut incised carvings around the fringes of the scroll-cut front section. The tools required are quite simple: a carver’s Vee tool, a small gouge and a plain round-nosed paring chisel. After experimentation in our workshop we think the time taken to complete the carving in the case illustrated would have been no more than two minutes. In order to understand clock cases of the 1880s to 1914 period, it is necessary to appreciate the rate at which clocks were manufactured within the competitive marketing climate at the time.

German, Austrian and Other Vienna-Type Wall Clocks

The term ‘Vienna’ is used to describe clocks made in increasing numbers from the middle of the nineteenth century in Germany and Austria, to satisfy a growing demand as European economies expanded. The term ‘regulator’ is often applied to Vienna clocks by the antiques trade, but this is almost always incorrect. In fact, a regulator is a special accurate clock, usually with a dead-beat escapement.

Although Viennas with American movements turn up occasionally, Brooks Palmer’s 1967 book A Treasury of American Clocks does not include them as an American clock type, although there are parallels with Connecticut wall clocks of the early to mid-nineteenth century. The exact origins of Vienna-style clocks with American movements are unclear but, since the American clock trade had adopted and adapted European black-stone clock designs, a similar imitation process seems reasonable.

Through more than a century of changing fashions, Vienna clocks evolved from early and valuable hand-made weight-driven clocks to the more commonplace factory-made spring-driven products that are more recognizable as Viennas.

From their introduction in the late 1700s, Vienna clocks evolved through a series of distinct styles up to the beginning of the twentieth century, each style shift following current tastes in domestic furnishing. A brief history of their stages of development is given below.

The transition from Biedermeier to baroque was a gradual evolution.

The Empire Period – Pre-1800 to 1835

At this time Austria was aligned with France, with Napoleon declaring himself Emperor of the Roman Catholic Empire. Empire-style architecture and furnishings were in fashion, with buildings displaying a straight-sided structure with pointed pediments. The laterndluhrstyle clocks of the time contain hand-made movements and are generally of good quality. They are plain and devoid of baroque curves, resembling a stack of three boxes: dial, trunk and a widening at the bottom for the pendulum. The structure of the case relies on thin wooden frames fixed to a rigid backboard and stiffened by panels of glass. Early Vienna clocks were weight-driven so they tend to be quite tall, to allow for the fall of the weights over the space of a week.

Biedermeier – 1835 to 1848

After the close of the Napoleonic period, the middle class rose to its ascendancy in the Biedermeier period (1835–1848). Society was on the change in Europe, culminating in the year of revolutions in 1848 when the people demanded rights. Even in England, which was governed by the land-owning establishment, the Chartist movement, campaigning for equal rights, reached its zenith in 1848.

These significant political events influenced fashions in furnishing and the style of Vienna clocks became simpler, with the original angular glazed boxes of the Empire period mutating into curves and the style evolving into the Serpentine style. There was a marked influence from the neo-classical movement that had been popular on and off since the Renaissance.

Serpentine and Transitional Styles – 1850 to 1875

Clock cases became increasingly decorated. The straight lines of the Biedermeier were replaced by flowing curves, and embellishments were added. As spring drives were introduced, it was possible to make the cases shorter.

Alt Deutsch and Baroque Styles – 1870 to 1895

Vienna clocks of the late nineteenth century are more plentiful. The Alt Deutsch style of the clocks stands out, with ornate cases that often feature full fluted Corinthian columns on the doors.

Baroque – 1875 to 1895

The baroque style was ornate, similar to Alt Deutsch, but distinguishable by the typically lavish carving and the asymmetric crown and sub-base. Baroque-style clocks do not have Corinthian columns. During this late period, exotic veneers including mahogany were used more.

Jugendstil – 1890 to 1914

The last stage of evolution of the Vienna clock was in the Art Nouveau style of the 1890s. It rejected frivolous embellishment and, so to some extent, represented a reversion to the Biedermeier style. The cases are plain and quite simple but often embellished with leaded glass and those flowing shapes that are so characteristic of Art Nouveau.

A parallel thread of evolution developed Dutch wall clocks into a somewhat similar style but without the glazed door.

Our Restoration Project

Our project had many of the problems frequently found in Vienna clocks. It arrived at our workshop having been in a damp outbuilding for decades and naturally it had deteriorated in the harsh environment.

Although it is of a type usually called Vienna – in other words, a wall-hanging clock usually associated with Austria and Germany – this one is American. It is only slightly unusual to find an American Vienna because the American clock trade seems to have utilized successful European designs. It has an American Newhaven spring-driven movement, which appears to be original to the case since there are no empty screw holes in the backboard where a different movement might have been mounted. The backboard is quarter-veneered in very thin walnut of a type usually called Italian walnut (in other words, it has a strongly defined grain structure of the type once used in herringbone inlays in early eighteenth-century furniture). The plain break-arch pediment is veneered and the arch in the top of the door had apparently at some time the same diagonal veneer pattern, traces of which remain.

An American movement in a Vienna clock is a little unusual. The general state of deterioration is apparent, but we were sure we had enough to work with.

Mildewed and loose veneers, losses and woodworm infestation – all the symptoms of prolonged exposure to a damp climate.

The main structural elements consist of top and bottom boards linked by a solid pine backboard and two glazed frame side panels. The glazed panels are one feature of Vienna clocks that persisted from first to last. The door is a simple softwood glazed frame with half lap joints at the corners; a semi-circular arch in the top of the door frames the dial. Walnut veneers are applied to the vertical edges of the top and bottom boards as cross-bands and the entire construction was further embellished with turned finials and a cornice moulding on the break-arch pediment.

Woodworm attack in veneered pieces tends to concentrate just under the veneer.

From the three empty holes in the top surface of the pediment, it is apparent that there were once three finials.

The quartered veneers on the back-board are in a very precarious state but there are minimal losses. This is a significant part of the clock case.

Another victim of the damp climate, the wood bezel that supports the clock dial has fallen apart at the glued joints.

The drop below the bottom-board is a characteristic of later Vienna types. Laying veneers on to curved surfaces is slightly more complicated (see Chapter 3 for detail).

We were able to get a very good idea of the shape of the missing decorative parts of the door from the imprint left behind.

A damp environment is never good for a clock and, as well as rust and corrosion in the movement, the case had also suffered from the ingress of moisture, which can lift veneers, loosen animal collagen glues and increase the likelihood of woodworm infestation. The case had lost pediment mouldings and all of its finials except for the stumps of two below the bottom board. The disintegration of the wood bezel that supports the dial is a good example of the type of damage caused by loss of adhesion through dampness.

There were a number of items on our work programme:

1.  woodworm treatment;

2.  damaged and loose veneers;

3.  missing veneers;

4.  missing finials;

5.  missing pediment moulding.

Woodworm Treatment

The Common Furniture Beetle (Anobium punctatum) has a well-documented life cycle, which gives clues about the best line of treatment. The female lays eggs in crevices on the surface of wood (in the joints or old flight holes). The eggs hatch into larvae, which then bore through the wood for up to four years. They can sense the surface of the wood and so they pupate just under the surface, after which they emerge between May and August from characteristic new flight holes as small brown flying beetles. These beetles then mate and perpetuate the life cycle.

Woodworm flight holes. First treat the wood and then decide whether to fill the old holes or not. The arguments are generally against. If you do decide to go ahead, opaque materials such as putty or car-body filler will always show.

Plenty of effective products are available to treat woodworm infestation. Their effectiveness is only as good as their absorption into the affected wood but, when they are applied properly, the active chemicals soak into the surface of the wood creating a continuous barrier through which the burrowing larva cannot pass. By a lucky coincidence, the sapwood preferred by wood-boring insects tends to be more porous than heartwood.

The presence of impervious finishes on the wood surface will limit the effectiveness, so polishes or varnishes should be removed prior to treatment.

One of the most frequent questions asked by visitors to our workshop is, ‘How do you disguise the woodworm holes?’ The answer is usually that we do not, or at least very rarely, because that would be an unnecessary intervention. If flight holes must be filled, the best advice is to avoid materials such car-body filler and putty because they are opaque and will be just as noticeable at the open flight holes. Waxes are effective as fillers and the preferred method for the darker woods used to be boiled beeswax mixed with the finely divided dust from rusted iron. Nowadays, restorers might prefer microcrystalline wax because it is pure and inert and several colours of natural ochre pigments are available. To make up and apply a coloured wax, warm the solid wax in an old steel spoon over a low flame (natural beeswax from honeycomb should be kept warm until it no longer boils and all the volatiles are driven off). Add the pigment and apply the mixture generously to the flight holes with a warmed paint knife. Scrape back the excess when it has solidified and apply the surface treatment.

Damaged and Loose Veneers

It can be impossible to match strongly figured veneers, and in our project almost all of the exterior veneers were no longer usable. We decided to rescue the quarter-veneered backboard but replace all of the exterior veneers with similar stem walnut. We considered patching what remained with the best possible match and then colouring the patches to blend because that would be a preferable conservation approach. However, in practice, patches laid across the original grain-line of strongly figured woods are almost always obtrusive.

Veneers in American clocks can be extremely thin, so when they become loose they are very fragile and prone to splitting apart. Consequently, removal and re-laying would be a high-risk, last-resort option. We decided instead to rely on a water-based resin wood glue to reattach the loose veneer. Once the glue is slipped under the lifted edges of the veneer using an artist’s paint knife or pallette knife, the veneer is pressed down with heavy weights placed on flat cauls lined with a thick fabric. If there is a risk of glue squeezing out and fixing to the cauls, a sheet of plastic film is placed over the veneer first (the best type is the plastic lining of breakfast cereal packaging).

Quarter matched veneers re-glued to the back-board.

It is essential to clamp the new glue joints tight.

Missing Veneers

Laying new veneers is easier; the two large areas of veneer on the front of the pediment and on the arch of the door were laid with the grain-lines on a diagonal to match the pattern on the backboard. The choices are glue film or water-based resin adhesive, but in special circumstances hot animal collagen glue could be used.

It should be apparent that the left/right symmetry of the veneers is an essential part of the design to keep in harmony with the backboard, so it is important to find a veneer with a strong grain structure and then lay it to create the symmetrical diagonals. There is always a tendency for the veneer to split off where the grain runs diagonally across the corner so it is best to cut the veneer oversize and trim it after.

When a significant proportion of veneers are missing, it is more likely that an acceptable finish can be obtained only by completely re-veneering. Matching veneers for colour and figure is difficult but finding something that is acceptably close will work only if it is not an obtrusive mismatch with the original. Remove old veneers with a paring chisel or apply some heat with a flat iron.

Missing Finials

When all of the finials are missing, there is obviously no extant pattern so research will be needed to identify the shape and size that is most appropriate. Online research, especially on marketing and auction sites, can be productive.

Missing Pediment Moulding

It is clear from the traces left behind on the pediment that the original moulding was an unbroken arch mitred to flanking mouldings, which were mitred around the front corners of the pediment.

The first step is to design a suitable moulding profile. There is nothing left of the original so we needed to design something that would convey the sense without inventing something complicated. Comparison with similar clocks is a good starting point and a simple ovolo should achieve the aim. Scale is important so a good drawing is helpful.

Second, we needed to establish the outer diameter of the arch moulding so that it can be turned on a lathe face-plate.

Drafting by hand on to paper or film works well but drawing software is far more convenient for all sorts of restoration and conservation work. The centre of the arch is not on the line of the top of the rest of the pediment, but three known points (width and greatest height) on the pediment are used to estimate the diameter of the arch.

Setting out detail for the replacement pediment coving.

Third, we needed to calculate or draw the angle of the mitre between the arch and straight sections of moulding.

Making up the moulding is a turning exercise, which requires a face-plate.

Removing the required moulding from the disc of the blank calls for some accurate measurement. The blank is deliberately chosen to be a few millimetres thicker than the required moulding and, when the inner edge of the moulding is defined with a groove, cut using a parting tool. The turned disc is then removed from the lathe and the excess thickness sliced off in the band-saw, liberating the moulding, which will now be of the correct thickness.

Screw a suitable blank on to the lathe face-plate first and then scribe the circle after.

With the blank thicker than the required moulding, it is just a matter of removing the turned blank and then removing the excess thickness in the band-saw to liberate the moulding.

Mitres are cut according to the design drawing.

The finished restoration. Check that the clock fits and everything works before final polishing.

Nothing spoils a cornice moulding more than a mismatch of angles cut into the mitres. In this arrangement, with flat mitres, when the tangent line is drawn at the intersection of the arch and straight, the bisector between the tangent and the straight is the angle at which to cut the mitre. It is easy to see that the original maker helped by arranging for that half-angle to be exactly 60 degrees.

Last, the mouldings are fixed into place, coloured and finished.

Careful setting out and advance planning will always pay off.

A late nineteenth-century German factory-made clock in the style of Dutch wall-hanging clocks. Not exactly a Vienna, but often described as such.

EXAMPLES OF TYPE 2 CLOCK CASES

Type 2 clock cases are of solid wood construction with access to the clock movement through a rear door.

English Bracket Clocks of the Period c.1700–1900

The English bracket clock developed in the late seventeenth century and soon became a prestige object for the wealthy land-owning classes. By the mid-1700s wealth had been distributed more widely and the new class of rich entrepreneurs of the Georgian age were spending their new money on decorative and complicated clocks that were the acme of the golden age of horological craftsmanship.

Cases are usually oak with quite thick hand-sawn veneers and delicate cast-brass embellishments. The replacement of ebonized woods and exotic veneers by mahogany after about 1730 coincided with a general shift in London clockmaking from longcase to bracket clock production. Clocks of this type made in the Georgian period in more or less original condition are valuable and the remedial treatments are usually more in the remit of the conservator.

A classic three-train bracket clock. The maker, William Hughes, was renowned for his musical clocks. (Steve Daniels)

Details of the door (left). Unlike the 19th century door on the right, there are no 45 degree mitres. (Steve Daniels)

From the method and detail of construction of early to mid-Georgian bracket clocks it is apparent that the case-makers adapted the techniques refined in longcase clock cases. The movement is mounted on a seat-board in much the same way as in a longcase and it should be similarly securely fixed. Styles of veneer often distinguish original from later work. In applying the veneers to door frames, for example, it is usual to lay the veneer as cross-band except it is butted together at the corners, not mitred as it might be in later provincial longcase clocks.

Stephen Daniel worked in London and was accepted into the Worshipful Company of Clockmakers in 1698. (Steve Daniels)

The glazed case is veneered in the ebonized style that was fashionable in c.1700. (Steve Daniels)

The movement is fixed on to a sub-frame within the case. (Steve Daniels)

The filigree cast-brass basket top is susceptible to damage. (Steve Daniels)

It is one of the features of high-status or valuable clocks that they have usually been carefully looked after and damage tends to be restricted to lost veneers, loose hinges, lost feet and damaged brass filigree work. The bracket clock style continued throughout the nineteenth century, with increasingly cheaper clocks being made, using mass-produced movements.

European Shelf Clocks from Mid-Eighteenth Century to c.1900 and Later

The rise of the Napoleonic regime brought about a leap in fashion, away from the flowing curves of French neo-classical and baroque to a more angular architectural elegance. Clock cases of this new style tend to include architectural shapes in black and gold. Several decades before the development of mass production, clocks were hand-made and the cases were equally costly to construct.

The clock case illustrated here is for a three-train quarter-chiming clock made by a prestigious Vienna maker. Very thick wood is used in its massive construction and at 530mm high it was obviously intended to be displayed in a large room. In common with most European clocks of this period, the wood is a dense, close-grained pine. The turned finial above the classical architectural pediment is at odds with the overall composition but we have no doubt that it is original. The brass castings, which are fixed on with small brass nails, all show traces of lacquer. As an alternative, gold leaf would not be unusual in clocks of this type and status.

The elegance of the French First Empire (c.1800) became fashionable throughout Europe.

The back door is a replacement and unfortunately the repair work included cutting slots into the inner faces of the side panels.

The gongs have been reversed, making it impossible to align the hammers correctly. The gong bracket is mounted on a rough piece of wood.

The lower back door that gives access to the pendulum for time regulation has been screwed to the case. One of the original catches remains.

The underneath removable panel remains intact, held in the case by two original steel catches.

Catches twist open to allow the door panel to be removed.

The fashion for black and gold was not restricted to the Napoleonic Empire. It was also popular in the equivalent English Regency period, with the same neo-classical devices, including animal and caryatid figures, being abundant.

The black colour on the wood surface appears to be lamp-black, applied either as black ink or as fine soot mixed with shellac polish. The black has rubbed from the edges to reveal the brown colour of the underlying wood. Whether or not the rubbed black should be reinstated is a matter of opinion and down to the preference of the owner.

English Shelf Clocks of the Late Victorian to Art Deco Period

Late Victorian Cases and Restoration Work

The shelf or mantle clock form continued to be popular for clocks made for smaller rooms and the Type 2 case is generally the most practical for pendulum and gong-striking clocks. During the nineteenth century, industrialization and consumerism combined to create both the means of production and the market for the evolutionary progeny of earlier English and European bracket and shelf clocks.

An Edwardian shelf clock. According to the trademark the movement was made by Badischen Uhrenfabrik, AG, Furtwangen, Germany, but it is not possible to say definitely whether the case was made in Germany for export to Ireland, or more locally made.

The vestiges of traditional cabinet work and the overall style strongly suggest a British origin for the case.

The style of Edwardian shelf clocks was mostly copied from Georgian bracket clocks, but they were made smaller to suit the smaller rooms of the new consumers.

The middle classes favoured good-quality, factory-made movements fitted into well-made cases that carried the legacy of the Victorian conservative establishment that tended to be oriented towards the neo-classical. As a result, the better-quality clocks of the 1880s to the 1920s are more European in their design influences and construction. By contrast, cheaper clocks of that period, favoured by the wage classes of society, were more American-influenced – ostentatious but in new styles.

Cases of English-style shelf clocks of the period continued to suggest cabinet-making skills and, in general, the appearance is often refined with an acknowledgement of the neoclassical in geometric or floral inlays in, typically, mahogany. Occasionally, the European baroque style surfaces, especially in European clocks exported to England.

A typical veneered shelf clock restoration project: This Edwardian clock case is missing a pediment coving from the front plinth moulding.

Chipped veneer is a result of a loss of the protective coving. Patching is difficult and the options are either complete replacement of the veneer on the top panels or, preferably, a neat cross-band along the edge.

The dull shellac polish is rubbed lightly with fine wire wool soaked in alcohol.

In late nineteenth- and early twentieth-century furniture, a mixture of white mineral and tallow (filling-in) was used to flatten the work prior to polishing. It reappears as the old polish is removed.

The most frequent restoration work on clock cases of this type involves repair to chipped veneers and the removal and replacement of original shellac polish that has degraded to an opaque greyish yellow.

The filling-in will lift with linseed oil.

Fresh shellac is applied to the cleaned veneers. Without replacing the filling-in, several rubs of shellac will be required to flatten the surface.

The practice of filling in mahogany and other fine woods prior to polishing was developed in the late Victorian period. Finely ground white mineral (marble dust, for example) was mixed with beef tallow and applied hot to the wood surface. When the shellac polish was applied, the marble dust became invisible but, with the passing of years, fine yellowish flecks appear as the polish degrades. There should be no necessity to remove the filling in but, with the original shellac removed, boiled linseed will again render it invisible prior to re-polishing.

Art Deco Style and Restoration Work

After the First World War, greater equality and improved civil rights changed society, but the mood of optimism about the future was tainted by economic depression and unemployment. For the masses across Europe and America who lived in poverty, it was the cinema that provided a welcome escape from the reality of everyday life. Hollywood and the European film industry attracted bright young designers and their work on the new movies went on to exert a profound influence on fashion and taste in all aspects of life. In addition, advances in materials allowed different shapes to be used, and facilitated new manufacturing processes.

The Art Deco style began to appear in the early 1920s and, although the technique of making moulded plywood objects including chairs and aeroplanes is more associated with the 1930s and 1940s, wooden clock cases of the Art Deco period are dominated by moulded plywood. The manufacturing process is simple, with layers of thin laminated wood being glued and pressed into a mould. It was a high-volume, low-cost factory process, creating seamless three-dimensional forms that would not be economically feasible otherwise. The most popular decorative veneers of the period were the varieties of walnut, the light woods, often figured, mahogany as a base against which to lay bold contrasting inlays. Chrome-plating was introduced in about 1930 and chrome soon became the icon metal of that decade. It was extensively used in hinged dial glass frames and bezels.

The design of shelf clocks was influenced by the system of striking or chiming the hours and quarters. Quarter-chiming clocks were popular and the adoption of a set of four or five or more brass chime rods required a clock case of sufficient width.

Art Deco styles were a complete jump from tradition made possible by new materials. The chrome bezel dates this clock to post-1930.

Contrasting veneers and the streamlined shape are characteristic of Art Deco.

The extra width of the case is specifically to accommodate the gong rods that chime on the quarters.

In our experience, restoration work on plywood cases is usually about shabby finishes, missing feet, loose door hinges and dents.

Shellac was still widely applied as a polish until the advent of modern sprayed chemical varnishes in the 1950s and thin veneers with shabby shellac polish are a feature of unrestored 1920s and 1930s clock cases. It is common to find that the shellac polish has deteriorated by absorbing tar from tobacco smoke. The symptoms are an opaque, crazed or crackled appearance for which the only remedy is removal and replacement.

Feet are usually of wood, either two or four plates glued to the base-board or bun-shaped feet screwed into the corners of the base-board. It is surprising how often those little bun-shaped feet go missing. It is not a difficult job but it does take a wood-turning lathe to do it right. The fixing screw should be well countersunk and the right type of screw is a tapered slotted wood screw, not a parallel cross-head chipboard screw. If the screw hole in the case looks oversize, we usually glue in a softwood plug and re-drill.

Likewise, the glass dial door hinges can be problematic. Usually, the glass is set into a brass rim that is often chrome-plated. The hinge is usually soldered to the rim so, when it fails, the easy way is to remove the old hinge by melting the flap with the tip of a hot soldering iron and then tinning and soldering on a new hinge.

Moulded plywood technology was in its infancy in the 1920s and 1930s and it is natural that the manufacturers learned from experience about how thick or thin to make plywood clock cases.

Impact damage to thin plywood can be pressed out from inside and stabilized by gluing additional veneer to the inside.

Discoloured and scratched shellac detracts from the overall intended appearance.

Plywood does not resist impacts well and dents are difficult to repair because they are invariably in an otherwise smooth surface, on which reflected light shows up any deflection. The best method we have found is to press out the dent from inside and then reinforce the area by gluing a patch of thick veneer on to the inside surface.

It is tempting to dismiss Art Deco clocks as unworthy of careful conservation and restoration but the same temptations are common to horology, which is why seventeenth-century clocks with original verge escapements are so scarce (and valuable).

‘Napoleon’s hat’ clocks were fashionable until the 1950s when modern designs made them look old-fashioned.

EXCEPTIONAL CASES

There are all sorts of clock cases that do not conform to our Type 1 and Type 2 categories and one remarkable type is found in marine chronometers. The point of a marine chronometer is that, before the days of radio, it had to remain accurate for the purposes of navigation until the ship made a landfall. Just one minute of inaccuracy in the ship’s time-keeping could result in a navigational error of over 17 nautical miles at the Equator. The precision-made balance-wheel chronometer movement was mounted on gimbals inside its protective brass-bound wooden case and it would have been the property of a ship’s officer.

The obvious high status of the chronometer and its case reflects the social position of the owner and, from the serial number on the instrument illustrated here, the date of 1840s is entirely in agreement with the expensive rosewood veneers applied to the case. We can conjecture that it was made for a British naval officer in the days of wooden battleships, thirty years or so after the Battle of Trafalgar, which confirmed the supremacy of the Royal Navy across the world’s oceans.

Chronometer cases such as this are rare and valuable and they often show the signs of scrapes and impacts. The need for restoration work on rare horological objects should be considered carefully. The objective should always be the preservation of the object of cultural heritage over cosmetic renovation.

Rosewood veneers on mahogany with the usual brass corner bindings. (Steve Daniels)

The case is double-hinged; the top section opens to reveal a glass plate that protects the chronometer. (Steve Daniels)

Chapter 7

Stone Clock Cases of the Nineteenth and Twentieth Centuries

This chapter is about the many different types of stone that are used in clock cases and how to restore and conserve them. Stone cases are mostly of marble, limestone or slate, but many different stones are used as inlays.

In the late nineteenth century stone was a popular material in clock cases. The fashion for black seems to have originated in Europe in the late nineteenth century but it spread to America quite quickly. Particularly desirable were the black stones, various marbles, and cases with more than one type of stone in them. The stone commonly called Belgian black marble was in great favour, although it was neither marble nor, in many cases, Belgian. The huge Belgian stone trade would import rough slate stone from various locations, cut and finish it and then reexport it. Green stone cases, often described as onyx but actually marble, were popular in their own right. Pieces of green mineral, especially the emerald-green malachite, were also combined into cases as ornamental features.

Stylistically, late nineteenth-century cases were usually architectural in character, made to look like ancient Greek temples, often with columns or pillars supporting pediments. Simple, more austere marble cases were particularly popular. Marble could also be used as a stand for the clock – French mantle clocks and skeleton clocks that have a glass dome covering the clock are often set on a marble base. Cast-metal ornaments made from brass or spelter often decorated the case, and gilding and gilt-filled intaglio engraving were widely used to create the impression of baroque opulence.

A French black slate clock case with decorative marble and gilded intaglio.

This German Junghans Brothers clock of the late nineteenth century represents the style and taste of the time. It imitates the classical architectural style that was popular in American clocks of that period, which European clockmakers eagerly imitated.

A typical black stone clock. Stylistically, the architectural layout has been combined with the characteristic Art Nouveau hour numerals. The copper used in the friezes is also an Art Nouveau feature. Although many black stone clock cases are slate, this one is limestone.

MATERIALS

Marble

Geologically, marble is a metamorphic calcareous rock, but many attractive limestones (which are sedimentary rocks) are sold as marble and sometimes it is difficult to tell one from another.

Marble is the product of alteration and recrystallization (metamorphosis) from dolomite (CaMg(CO₃)₂) or calcite (CaCo₃) under great heat or pressure. This gives marble its typical granular structure; although it cannot always be seen with the naked eye, one of the diagnostic features is the twinkling reflection of light on a fractured surface. The duration of metamorphosis affects the size of crystals; the longer the rock is influenced by pressure and heat, the bigger the crystals grow. Metamorphic rocks do not display any traces of fossils or sedimentary structures. Other non-calcareous minerals present in the sedimentary limestone rock do not remain unaltered; they are re-composed into characteristic suites of metamorphic minerals and redistributed through the rock matrix.

Marble is easily cut with a steel saw. This is the replacement part that we needed for a clock-case restoration.

The colour of marble may vary, from white, grey and black to green, brown and pink. It can also show included veins, patches, mottles or other features. Some marbles are translucent to varying degrees.

Marble is quite a soft material, around 3 to 4 on the Mohs scale of hardness, but it can be quite variable. A very simple test differentiates dolomitic marble from calcareous marble. Calcite marble dissolves in dilute hydrochloric acid solution with a powerful effervescence but the dolomitic equivalent dissolves more slowly, with only intermittently visible bubbles.

Connemara marble from the west of Ireland shows the wide variety in colour and texture that is typical of the material. The composite slab illustrated is of a type that used marble waste products in the production of decorative floor tiles. We salvaged this piece to make replacement parts.

Calcite dissolving in dilute hydrochloric acid solution. The effervescence is visible and even audible.

Marble and limestone are slightly alkaline, so they can be affected by acidic substances. Changes in temperature and humidity can also affect marble quite significantly. Some marbles have a tendency to warp, a strange rheological feature they share with several of the white evaporate type minerals. Humidity can affect marble as moisture gets into the pore structures in the matrix of the mineral grains, with the result that the granular structure starts to crumble.

Limestone

Limestones are sedimentary rocks. Layers of particles are deposited from suspension in water and cemented together by a high calcium carbonate content in the water so typically they are formed in shallow tropical seas. The solid mineral particles are characteristically fine-sized weathering products, originating from a wide range of continental rock types – magmatic, sedimentary and metamorphic. Any super-saturated calcium carbonate solution is likely to precipitate crystalline calcite and careful examination usually gives clues about the geological processes of deposition and rock-forming.

Limestones, especially when used in clock cases, usually have a very fine granular structure with a wide variety of colours, from pale straw to dark grey. Depositional layering and fossil traces are common. (Fossils are used by geologists to date the sediments because the species tend to evolve over geological time.) There can be many different markings and from the same stone it is possible to obtain a wide range of patterns and textures, depending on such factors as the quarry location and cutting direction. Like marble, limestone reacts easily with dilute hydrochloric acid so it is vulnerable to erosion from the effects of temperature and humidity.

A historical repair. A dislodged pressure fracture has been re-attached and it is clear from the nature of the fracture that the material is more isotropic than would be expected of slate. Uneven fracture surfaces are typical of limestone and marble.

Many different limestones that can be brought to a high polish are sold as marble. Pure and almost pure limestone is white but most limestones contain more than one mineral that gives them different colours. One of the most common components in limestones is clay, either as a primary mineral deposited during the sedimentary rock-forming process, or as the products of secondary alteration of the primary deposition mineral. High clay content usually indicates that the rock will take a higher polish. Limestone is not suitable for intaglio engraving because of its coarser and more irregular matrix.

Because of the huge variety in mineral composition, limestones can be categorized in many different ways. The Dunham and Folk systems of classification both use variations in grain size and fossil content to define limestone rock types.

Clastic or detrital rocks are products of erosion of already existing stones. Many of the commercial breccia or Breche marbles are really clastic limestone.

Chemically formed limestones build up when calcium carbonate precipitates from water. Onyx marble is one of these chemically precipitated limestones. It is perceived as horizontal stalagmite because it forms in the bottom of non-flowing water areas. Despite its name, onyx marble does not contain onyx (a cryptocrystalline quartz and far harder than limestones or marbles), and it is not metamorphosed, so it is not marble either. Onyx marble is actually an exceptionally fine-grained and translucent calcite. It is usually striped, with colour varying from nearly pure white to ivory, yellow, green, reddish, red-brown and brown. It is very popular and is highly valued as an ornamental stone that is easier to work than real marble.

Stalagmites and stalactites are precipitated from solution when water saturated in calcium bicarbonate drips from the roof of a calcareous cave. The mineral builds up in layers to form stalactites in the roof. Beneath the hanging stalactite, a stalagmite grows upwards as calcium carbonate continues to precipitate from the running water. Sometimes, calcite covers the entire floor or walls of cave.

Limestone can sometimes look similar to marble but marble is translucent, with a crystalline matrix composed of tiny crystals. This piece of ornamental marble was found in an architectural salvage yard. It had been left out in the weather and the surface has been etched by rain water. The green colour is an algal growth.

Organic limestones are mostly or entirely composed of one or more types of fossilized shellfish, coral or algae. Shells of living creatures form from calcium carbonate that is filtered from water by the animal. The empty shells that are deposited are preserved as fossils, either whole, partially broken or completely pulverized.

Slate

Slate derives from shale or mud-stone-type sedimentary rocks that were composed originally of clay or silt-sized mineral fragments, clay mineral or volcanic ash. Low-grade regional metamorphosis causes changes in the mineral composition and structure of the shale. With increasing metamorphosis, clay minerals re-form to micas and the slate turns first into phyllite and then, at extreme temperatures and pressures, to mica schist.

A piece of monumental slate from an architectural salvage yard. It had been blackened and then polished as part of a memorial stone. The mid-grey colour and layered structure are visible.

The texture of slate tends to be homogenous but foliated, like the pages in a book, because the parallel orientation of platy minerals gives it a characterized repetitive layering along which it cleaves easily. This characteristic makes it attractive as it can be cut easily into thin sheets. Unlike marble or limestone, it absorbs only small amounts of water, which makes it very resistant to the detrimental effects of weathering from ice expansion within the rock matrix.

Grain size is fine or very fine, as small as clay-sized particles and not visible to the naked eye. It scores a hardness of 3 to 5 on the Mohs hardness scale so it is relatively easy to work. The colour usually ranges from mid-grey to dark grey but it varies with the kind of included organic substances, as well as the oxidation level of iron. Occasionally, shades of blue, green, red, brown, buff and purple are seen.

Mineralogically, slate mostly consists of quartz, clay minerals and muscovite, but common accessory minerals are biotite, chlorite, and the iron minerals haematite and pyrite, which tend to produce red weathering products.

CLEANING STONE CLOCK CASES

Most stones are susceptible to staining from tobacco smoke, oils, resins or plaster. The oxidation and corrosion products of different metals also cause staining by being absorbed into the rock matrix.

As a natural and therefore inherently unpredictable material, stone may be sensitive to harsh cleaning methods or detergents. Consequently, the most important principle of cleaning stone surfaces is to use gentle cleaning agents – if the stone surface is damaged during the cleaning process, it cannot be put back. It is of the utmost importance to select a cleaning method that will not cause any short- or long-term damage or alteration.

Mechanical Cleaning

The process should start with gentle mechanical cleaning performed with a soft brush and a vacuum cleaner with a piece of fine cloth on the nozzle (this prevents loose parts getting sucked in and lost). It mainly removes dust and surface dirt.

Because calcium carbonate in marble and limestone is insoluble in water, most cleaning methods are water-based. However, marble should not be in contact with water for a long period of time, because it can get into the pore structure and cause stains. Sometimes, moisture condensing from the atmosphere is enough to cause stains and erosion. For these reasons, it is always best to use de-ionized water for cleaning stone that is even slightly porous.

Some varieties of limestone can be even more porous than marble, and absorb humidity in the air more easily. In these cases, absorption of the cleaning water is unavoidable but large amounts of water should be avoided. As on marble, soiled cleaning water can cause staining and reduce shine on polished limestone, with the surface becoming blemished, even at a microscopic level. The use of strong, bleaching cleaning agents, acids or powdered detergents can lead to long-term damage when they are absorbed into the stone surface. The damage caused by these caustic or corrosive substances may not become visible until years after the original exposure.

Stain Removal

The first step after mechanical cleaning is to start removing water-soluble dirt and soot with clean warm water and a soft brush or sponge. The amount of water used should be minimal – partly because of the problems it can cause with porous stones (see above), but also because case parts are usually attached to each other with plaster of Paris. Water softens the plaster and can cause parts to fall off. Sometimes a 1:1 solution of water and a pH-neutral soap can be used.

Poultices

In Conservation of Building and Decorative Stone by John Ashurst and Francis G. Dimes, there are many excellent recipes for different stain-removing poultices. The following recipes and instructions are from that book and from other publications including best practice guidelines.

When stains are insoluble in water, more effective cleaning methods need to be used. One gentle and efficient method for cleaning stained marble and limestone is to make a poultice from attapulgite or sepiolite clay. This may successfully draw the discoloration out of the stone. Darker-coloured and sometimes blackened slate does usually not need this type of cleaning method, but it is safe to use on it as well.

Sometimes, a hot lime poultice can be effective for cleaning limestone, bringing dirt up from the stone’s pores and softening the stains. It may be used just like that but it is also possible to add different agents. It is important to keep a poultice wet by covering it with plastic and, if needed, to spray it with water. The stone surface should also be wetted with water or sometimes with cleaning solution before applying the poultice. A poultice can be left in place for as long as a full day, depending on how resistant the stains are to removal. Most of the poultice can be removed with a wooden or plastic spatula, and remaining traces wiped off with damp cotton wool.

The Mora-poultice, named after its developers Paulo and Laura Mora, is based on a chelating agent. Ethylene diamino tetra acetic acid (EDTA for short) softens stains effectively by causing the calcium and iron salts to dissolve by complex formation. It is a mild acid and, like other acids, it should not be used for general cleaning. This poultice can also remove rust and smoke stains.

The recipe is as follows:

1000ml water
60g ammonium bicarbonate (NH₄HCO₃)
60g sodium bicarbonate (NaHCO₃)
25g EDTA
10g surfactant disinfectant
60g carboxy methyl cellulose (cellulose based wallpaper glue is an easily available option)

Rust Removal

Rust, oil and cuprous stains (from metals containing copper) are impossible to remove with plain water. Old oil stains are especially hard to remove because they have been absorbed into the stone’s pores and oxidation has darkened the colour. With tough stains it is important always to test different cleaning methods before carrying out the cleaning.

Iron stains often start from corroded fixings.

Rust stains are caused when the presence of moisture starts a corrosion process in iron or steel. Rusting screws and other fixings in holes tend to expand to the point where they split the stone while releasing a red stain through the stone matrix.

To deal with rust stains, make a solution of one part sodium citrate to six parts water, then add an equal volume of glycerine. The addition of attapulgite clay creates a smooth paste, which is then used in the same way as other poultices.

For removing very tough stains, one different method that can be tried involves mixing sodium dithionite to attapulgite clay and wetting the surface with the solution described above before applying the poultice.

Cuprous Stains from Oxidized Copper

The green products of oxidation of copper and its alloys cause stains to permeate through the stone matrix. Remedial measures involve remobilizing the copper ions and removal into a clay-based surface poultice.

The recipe is as follows:

1 part ammonium chloride (NH₄Cl)
4 parts powdered talc or attapulgite/ sepiolite clay
10 per cent solution of ammonia-water

Unlike other poultices, this one is left to dry and then removed with a spatula, wiping the residue off with water. It is safe to repeat the procedure as many times as needed in order to remove the stain.

Oil Stains

Different solutions of warm water and detergents are effective methods of cleaning oil stains. Vulpex liquid soap is a widely used detergent for different types of stains. Its pH is 10.5–11.5 and it is soluble in both water and ethanol. It does not form any foam and stays active while it is on the surface being cleaned (usually five minutes). Depending on the stain, the solution should consist of 3 to 9 parts of water and 1 part soap. Because it removes oils very effectively, protective gloves are recommended. After cleaning the surface should be wiped thoroughly with clean water.

If washing with soap solution fails, the following poultice can be used:

1 part acetone (C₃H₆O)
1 part isoamyl acetate (C₇H₁₄O₂)

Undyed cotton cloth is dipped in the solution and placed on the stained stone. A clay poultice can be used instead of the cloth if the stain proves to be stubborn; the poultice can be left on the stain for as long as three days but, in order to control the evaporation of acetone, it should be covered with a sheet of polythene.

Biocide solutions (to remove harmful organisms) can also be used on slate, marble or limestone. This type of solution is more likely to be used on buildings and statues rather than clock cases.

Self-Adhesive Tapes and Labels

It is common practice for auctioneers to stick self-adhesive lot number labels on to stone clock cases and, occasionally, self-adhesive tapes are used to keep case doors closed. The adhesives can leave a very stubborn residue if they are left in contact for a long time. Solvents such as ethanol and turpentine can be tested to soften the stains (although ethanol should be avoided if shellac polish is present). Even when all the glue is removed the outline of the tape might still be visible. That would mean that the adhesive has been absorbed into the stone matrix and may have caused the surface to corrode.

Solvent test on an old tape-glue stain on a slate clock. All traces of contamination are removed before applying a black pigment to the stone surface.

CONTINUING PROTECTION FOR CLEANED STONE SURFACES

Traditionally, beeswax was used to protect stone surfaces and give the shine a finishing touch, but recently it has been found that it is not the best option for stones because of its chemical reactivity. It can also turn yellowish brown over time, like all organic waxes, especially if it has been mixed with linseed oil. In this case the mixture will turn to complex substances that are very difficult to remove.

A safer choice is to use microcrystalline wax, which is less acidic, chemically inert and free from fatty acids. It is also more impermeable to fluids and protects the stone more effectively from contaminants in the atmosphere. Like other waxes, microcrystalline wax is mixed with turpentine to prepare a softer texture for application.

In most cases, slate was artificially coloured in order to achieve the deep black that was more popular than the natural greyish colour of the undyed material. Traditionally, Indian Black ink was used for this purpose. Basically, it is the same thing as the pigment carbon black, more specifically lamp-black, mixed with water or ethylene glycol and binding agents, such as gelatine, gums or resins. There are also commercial blacking substances that are effective and safe to use.

Microcrystalline wax is preferable to beeswax because it is inert.

STRUCTURE AND RESTORATION

Removing the Pendulum and Movement

Before studying or treating the stone case, the clock movement should be removed. A clock should not be moved with the pendulum hanging from its suspension because it is quite fragile and prone to damage. The beat of the clock – the evenness of the swing and the action of the escapement that results in the ‘tick tock’ – may also be disturbed. As a result, in accordance with the first principle of conservation – respect for the object – the first action before moving the clock is to remove the pendulum bob.

Typical arrangement of a pendulum suspension. The back of this late nineteenth-century German movement shows the relationship of the crutch – which is connected to the clock escapement and drives the pendulum – to the pendulum suspension. The suspension is supported at its top end by a transverse pin; at the lower end there is a loop from which to hang the pendulum bob.

On most late nineteenth- and early twentieth-century clocks the pendulum bob hangs by a small hook from a suspension arrangement that is the equivalent of a pendulum rod. Sometimes a pin must be removed or, in some cases, the hook hangs from a silk thread. Lifting the pendulum bob gently will usually release it from the suspension and it can then be removed from the clock case.

Unlike American cast iron clock cases, the movement is not fixed directly to the case. French-style movements in stone cases are round and are held in position in the case by clamping the dial, to which the movement is attached, and the back-door bezel or back plate to each other with two metal straps. The back bezel plate is attached to these with two screws. When loosening these screws the dial should be held with the other hand so that it cannot fall off when the screws are opened. When the screws are removed the back piece will detach and the dial and movement attached to it can be removed by being pulled forward.

Before cleaning the dial, the movement must be detached from it, but first the hands must be removed. The minute hand is usually attached to the end of the minute or centre arbor by a transverse pin through the hole near the end of the arbor but occasionally a screw nut is used. The hour hand is almost always a friction fit and will come off just by a combination of careful pulling and twisting. The movement is in most cases attached to the dial with three or four tapered pins, but the style of fixing has been modified over the years by various innovations.

Dial, movement and back door removed from the case and attached back together to illustrate the fastening mechanism.

Detail showing the two connecting screws that attach the movement and dial assembly to the back-door assembly.

Three posts holding the movement on the dial.

The back of the dial with the movement removed.

Make sure that you are removing the pins holding the movement on the dial and not the pins that hold the movement’s front and back plate together.

Composite Stone Clock Cases

There were two common methods for the construction of stone clock cases. The simpler clock cases were made from just a few parts shaped from solid blocks. Using this method the case was very heavy and, with some consideration for the materials and production costs for the mass market, a cheaper but more complicated type of stone clock case was developed. The structure of a composite stone clock case relies on a covering of thin plates of the decorative stone attached to an inner case made from cast-stone plates. The result was a thinner but stronger case, but more importantly it was also easier to produce in a factory.

The adhesive used to attach stone plates to cast stone is usually a shellac mixed with stone dust, ground from the waste products of the same stone as the decorative outside of the case. Testing the materials that are present is still necessary during any significant restoration or conservation.

First, in order to remove remnants of adhesives from the loose components and cast-stone core, they are gathered together in a container. Shellac was surprisingly widely used in all sorts of applications, including bulk adhesives. To check that the adhesive material present is shellac-based, its solubility can be tested with ethanol. After the test has been performed, a small amount of ethanol can be added to the salvaged adhesive and left in a closed container to re-dissolve the shellac. After a day or so, when the adhesive has turned into a smooth thick paste, it can be applied warm to both surfaces and the loose stone sheet attached to the core of the case. Gentle pressure should be applied until the adhesive is dry but it is important not to apply too much pressure with the clamp because stone is brittle. If resin trickles from the seams it can be wiped off with a spatula. After the resin has hardened, any clamps can be removed and any residues of resin wiped off with ethanol

Two clocks pictured from the back to show how the outer layer of the cases are constructed. The greenish case is made of Swedish green marble, commonly referred to incorrectly as onyx. (Onyx is as hard as glass, about 7 on the Mohs scale of hardness, and it does not react with hydrochloric acid because it is formed from silica mineral.) The black case is in the Art Nouveau style and has a very typical construction for a stone case.

Pieces of shellac and stone dust mix removed from the slate veneering.

A shellac and stone dust mix dissolved in ethanol and spread on the cast-stone core and stone slate.

The piece is clamped to the case with wooden blocks between it. The block protects the stone surface and allows the pressure to be applied on the piece more evenly.

If it is impossible to re-use the original adhesive, or if there are missing pieces, a putty can be made up by mixing acrylic or polyester resin with stone dust. The putty mix is thixotropic (it becomes more runny as it is mixed). The easily spread and mouldable mixture can be applied with a spatula but it is better to tint the putty with pigments to suit the original stone rather than paint the patches. Retouches made with plaster of Paris are not usually durable and it is very difficult to achieve a match with the original stone.

The wooden base of the stone case. Small screws attach to wooden blocks fixed inside the case. The large nut holds the gong in place.

The bottom board of the case may be wood and screwed in place, or it can be solidly attached to the case walls and not easily removable. In these types of movement, the bell or gong and pendulum can be removed from the back or from the front of the case.

Metal wire attachments inside the case. Part of the cast stone is painted black from the inside to make the appearance of the case more uniform.

The stone or reconstituted stone components of the case are attached together with thick metal wire ties bonded to the cast stone with plaster of Paris.

Case Decoration and Ornament

Case surfaces might be decorated with gilded engravings (intaglio), brass, tortoiseshell, mother of pearl, ivory or stone inlays. If the decorative parts are allowed to remain loose, they are likely to disappear. Many of the inlay materials are very fragile and should be handled with care when being cut.

Fine stone dust created when stone is cut or ground is potentially harmful if it is breathed in.

A new inlay piece should exactly match the gap in the stone to which it is being attached. Most decorative stones used in clock cases are soft enough to be cut and shaped with steel tools. The same paste that is used to retouch cracked pieces is also suitable for attaching inlay pieces.

Sometimes, whole sections of the decorative stone slates are missing and need to be replaced with new components. Fitting the new part into the case should always be done carefully, to avoid damaging the original. As a last resort, if the whole structure needs to be dismantled, care should be taken when removing the plaster of Paris that holds the metal wires in place. That can be done by just scraping the plaster with a scalpel or equivalent. Alternatively, if it is very tight or out of hand’s reach, the plaster can be broken by gently tapping the stone pieces with a hammer so that they come loose. Before taking any action, the case should be thoroughly examined and the method of construction fully understood.

The outer stone should be protected with a wood block so tapping with a hammer will not cause any damage. When the parts are detached, the necessary restoration work can be carried out and the case re-assembled, with the metal wires being re-attached in place with new plaster of Paris.

Ornamental columns are often hollow, made from thin pressed brass, and are often attached to the case with threaded rods.

Abrasive papers. The roughly flattened stone surface is gradually smoothed using progressively fine abrasive papers (available from car-body suppliers). They are used with soapy water.

Sanding and Polishing

After repairs, a scratched case can be sanded back with progressively finer wet and dry abrasive paper, working with soapy water. If sanding and shaping are necessary, it is important to remember that stone should always be worked wet. The fine dust that forms from shaping stone will easily become airborne and spread widely; it is very harmful when inhaled. Abrasive paper also needs to be frequently rinsed with water because the stone dust will clog it.

The weathered and corroded surface comes off quite quickly with 220-grit abrasive paper. The depth to which the surface is etched will determine the amount of rubbing-back that is necessary to create a flat polished surface.

After working through the grit grades from 220, through 400, 600 and 800, the job is finished with 1200 paper.

There is a progression from coarser paper to finer, typically through the grit sizes 220– 1200, in steps of about 200. After the stone has been sanded with the finest paper, it can be polished. There are many suitable polishes available but the one chosen should be appropriate for the particular stone that is being worked, and should not contain harmful, corrosive, or otherwise reactive substances. Always follow the instructions.

Sanding with wet and dry paper may not be necessary if the scratches are only small as they will tend to blend in and disappear with a wax polish (see below).

After polishing, the recommended surface treatment is a coating of microcrystalline wax. This will protect the surface and fill any small cracks; it should be applied with a soft, clean cloth or brush. Carefully warming the stone surface with a hairdryer will cause the wax to melt and fill the cracks, but there are a number of issues to consider with the warming process:

•  If the case has gilding on it, the heating may dislodge the gold leaf.

•  Some types of stone crack easily if heated too much.

•  Sometimes, cases have been assembled with adhesives that can soften with heating.

After cooling down, the extra wax can be removed by rubbing with a piece of cotton fabric. The procedure will also give the surface an attractive final polish.

Polished marble surface. The etching is still visible so we might have to start again with the 220-grit to achieve a less pitted surface.

Gilded Intaglio or Incised Carving Repairs

When cleaning the case, incised engravings should also be cleaned. This should be done carefully because, even if it seems that the gilding has worn off, it may just be obscured under a heavy layer of dirt. Debris from cleaning tends to accumulate in engravings, covering the gold leaf.

The question about whether or not to replace gilding naturally involves wider questions about conservation, but if the aesthetic character of the clock case has been lost along with the gilt decoration, then there is a strong argument in favour of reinstatement. Once a decision to replace gilding has been made, the remnants of the original gold leaf should be completely removed before re-gilding. Study whether the original gilding is pure gold leaf or a synthetic alloy, which is slightly cheaper. (However, the cost of gold leaf for a typical incised carved clock case is so trivial that pure gold is usually the better option.)

Internal carvings being cleaned with a soft wooden stick.

Removal of old gold leaf is most conveniently done before the final application of wax to the case. Scrape out the old gold leaf with a needle, scalpel or other similar tool that fits in the engravings, making sure not to scratch the stone surface. When the engravings are clean, the case can be waxed; this will isolate the stone from the adhesive used to attach the gold leaf.

Suitable adhesives for applying gold leaf to stone clock cases are the oil gilding sizes. Once applied, the size develops a tackiness – the approximate waiting time after applying the size is marked on the container (typically one hour), along with the manufacturer’s instructions. Gold leaf can be loose between sheets of paper or it can be attached to a transfer sheet. Loose gold leaf can be lifted with a gilder’s tip (a specially designed brush for gold leaf) or any clean soft brush. If the leaf needs to be cut into smaller pieces it can be done on a gilder’s leather pad with a gilder’s knife.

Gold leaf is applied by lifting the loose leaf with a brush or even a piece of cotton wool and gently placing it on to the size. It is then rubbed very gently so that it adheres properly on the size but does not break – the size will still be soft and unstable. The gilding is left to ‘set’ for as long as the instructions recommend and then the excess leaf is softly removed with the same brush or cotton wool, using a circular rubbing action. Quite often, there will be small parts that have to be re-gilded and that can be done by applying more size and repeating the procedure. Two applications of gold leaf will give the best result. Transfer leaf can be simply laid on the right place and the paper rubbed with cotton wool to detach the leaf, but this is not really satisfactory for incised carving.

When all the gilding is covered properly, the size should be left to dry thoroughly; usually a few hours will be enough, but longer is better. Some extra gold always attaches in unwanted areas and this can be removed with a soft brush or, if it is very tightly attached, with a wooden stick. When the result is satisfactory, the gilded area should be covered with microcrystalline wax to protect it.

It is not unusual to find that attempts have been made in the past to repair damaged gilding with gold paint. This should not be done for two reasons: the result differs from the original gilding and the solvents in the paint can soak into the stone surface, leaving marks that look like a halo around the gilding. Because gold paint can be very stubborn and might require strong solvents, the safer method of removal is rubbing with the finest grade of wire wool (0000). The erosion caused by gold paint is irreversible and can only be removed by sanding the surface. Usually, however, the risk of losing the detail of carvings is too great and it is not a recommendable action to take.

Gold paint was carelessly applied in the past outside the edges of the carvings.

After removing part of the gold paint with finest wire wool, it can be seen that the gold paint has eroded the slate surface.

CASE STUDY: FRENCH ROBLIN BLACK SLATE CLOCK CASE

This clock was produced by a good Paris maker, towards the end of the nineteenth century but prior to the introduction of the Art Nouveau style. Brian Loomes’s Watchmakers and Clockmakers of the World lists the maker as ‘Roblin & Fils Frères, Paris c.1875–c.1880’. Being a good-quality clock, it would have been somewhat more expensive than the average item. Its simple design and minimal gilded engraving ornaments would have appealed to the middle classes, who saw themselves as more refined than the lower waged classes, who generally favoured the more lavish baroque styles.

Roblin slate clock case before restoration.

In common with most European stone cases, this one has a pale grey cast reconstituted stone inner case to which the dark grey exterior slate parts are fixed. A thin brass tube is used between the dial and the circular back door to support the movement and provide an inner dust barrier.

The clock also has a solid cast-stone base with a glued green paper on it. This is slightly unusual, as a wooden base screwed in place would be more common. Under the paper it is possible to see the outline of metal wires that hold the parts together. This kind of base not only makes the clock a little heavier than the equivalent wooden base, but also complicates the restoration procedures if dismantling should become necessary.

The case itself has some minor chips on the corners and a few scratches. The gilding in the engravings is quite worn off and dirt has accumulated in the engravings.

Sheet metal tube inside the case.

Solid cast-stone base with glued-on green paper.

Muck- and grime-filled internal carvings, a scratched surface and some liquid splashes.

The material was tested with dilute hydrochloric acid solution and the resulting effervescence confirmed that it is calcareous. Geologically, it is either a calcareous slate or siltstone or an argillaceous limestone, but in any event it is a matrix of very fine rock particles cemented together with calcium carbonate. The other significant characteristic is a foliated structure, which suggests a calcareous slate. The appearance of the sub-conchoidal fracture surfaces, where it has chipped from the corners, is more in agreement with the slate classification for the material.

Lighter spots all over the case seem to be some kind of discoloured superficial substance. They can be seen as small spots distributed over the lower parts, and larger areas around the dial and sides.

After the case had been studied, it was cleaned with a small amount of water and extra fine (0000) wire wool, the moisture being wiped off immediately with a clean paper towel. This initial cleaning also removed some of the blacking from the stone. When thoroughly cleaned the state of the gilding became clearer: it was partially worn away and a decision to re-gild was taken. Residues of old gold leaf were removed carefully with a steel needle and scalpel, and the round pits were gently cleaned with a twist drill bit rolled in them.

Discoloration around the dial.

The case had suffered many scratches on all the major surfaces, so it was carefully sanded with wet and dry abrasive paper. Care should be taken not to use any more water than necessary during the rubbing back process because water getting into the joints can cause them to loosen. It is a good precaution to protect any areas not being worked on with plastic film (attached with masking tape if needed), and to wipe the sanded surface dry with clean paper towel every time when rinsing the abrasive paper.

Most parts were started with 400-grit, but some with deeper scratches needed 220-grit first. It became apparent that marks had been caused by a liquid dripping on to the clock case and the drop-shaped traces seemed to be very hard to remove. When it was sanded to the point at which only the edges of the drops were visible, it was possible to see that they had been etched on to the stone surface. Although slate itself is a reasonably resistant and durable material, we suspected that the calcareous fraction of the stone may have reacted with the unknown liquid.

The whole case sanded with 400-grit abrasive paper. The light spots around the dial and elsewhere on the case seem to become more visible.

The same effect of a series of uneven marks was present around the dial and on the case sides, and the marks around the dial followed the edge too systematically to be explained as natural to the original surface of the stone. It was most likely that cleaning with a strong or acidic cleaning agent had caused erosion of the stone surface. This is a very good example of deferred damage caused by chemically active substances on relatively soft or vulnerable stone surfaces.

The case was sanded down through the paper grades to 1200-grit, then polished with a paste made from cerium oxide and water, using a soft cloth dipped in to the paste and polishing one part of the case at a time. Spent polish was rubbed from the finished areas with a damp cloth to keep the case tidy.

It is not vital to use cerium oxide power as a fine polish – commercial polishes are available – but it is preferable because it is chemically neutral. It is important to make sure that the polish is suitable for the stone being treated so that it will not give rise to the sorts of deferred damage seen in this clock case.

When the polished appearance of the case was satisfactory, it was checked again for any residue of polishing paste, rubbing carefully over the surfaces with clean, damp cotton wool or a cloth. The engraving was cleaned with a toothpick or cotton swab.

The next stage was to blacken the case with Indian Black ink, which is applied in circular movements with a piece of clean cotton wool dipped in the ink. It should be left for a while and then any extra ink is removed with clean cotton wool. It is left until the next day to dry thoroughly and then waxed with microcrystalline wax.

After this the engravings were gilded using a loose 23.5-carat leaf on one-hour oil size. The size is applied only in the engravings with a small brush and left for about an hour, after which the gold leaf is applied with a soft brush. It is left to dry for a couple of hours and then the extra leaf that has attached itself outside the engravings is removed with cotton wool. This cleaning procedure tends to remove some gold leaf from the engraving as well, so the gilding procedure needs to be repeated to give a full cover of gold. A covering of microcrystalline wax is then applied to protect the gilding. (Unlike synthetic gold leaf, 23.5-carat gold will not tarnish so the wax is not to protect from oxidation, just to protect the microscopically thin layer of gold from physical damage.)

Gilding in process: Gold leaf applied and waiting to be removed around the internal carvings.

Blackened, gilded and waxed case.

The back door, which is of patinated brass, was covered in a thick layer of grime. It was decided to remove the grime but leave the patina on the brass. A solvent test was made with ethanol and white spirit, which removed some of the dirt. As a conservation matter, mechanical cleaning to remove the patina would be an unwarranted intervention – in general, polishing the patina from metal surfaces is a mistake that well-intentioned restorers are apt to make.

A heavy layer of grime on the back door.

Solvent test and careful cleaning on the rim; under a heavy layer of grime some patina has worn off and a copper-coloured brass surface is visible.

Merely wiping with solvent was not enough to remove the thick dirt layer, so the door was left to soak in ethanol for two hours. Even after that, the grime was not sufficiently soft to remove, so the soaking was repeated with white spirit. The grime was then soft enough to be removed with a soft brush and cotton wool.

The restoration of a stone clock case follows a well-defined series of steps, which start, with identification of the clock in its social and historical context, and an assessment of the nature of its materials. Test pieces are often used so that we can stick as far as possible to the principles of good conservation. We were careful throughout not to do anything that might cause the sort of deferred damage that was already evident on the clock case, and had to be rectified. Balanced judgements were made about rubbing back the surface of the clock case to remove scratches. There were arguments for and against: on the one hand, the preservation of the object had to be considered, but on the other hand there was an argument for reinstating the original aesthetic composition. Copies of all the records, including workshop notes, photographs and sketches, will go to the owner of the clock and hopefully the clock and the records will remain together for the benefit of future guardians and restorers.

Chapter 8

Metal Clock Cases of the Nineteenth and Twentieth Centuries

SOME HISTORICAL BACKGROUND

The earliest metal clock cases are known to date from the fourteenth century, but, as very early clocks are scarce or non-existent, hardly anything is known about the relative proportions of metal and wood clock cases from that time. Since wood is relatively vulnerable, it is naturally more susceptible to all sorts of damage and destruction so more metal cases might be expected to have survived. Portable clocks, in particular, were made from iron or brass (a tradition that can be seen in nineteenth-century carriage clocks) and fitted with handles in the sides or on the top of the case. A variant of the portable clock was the table clock, which had a very similar case, often drum-shaped with a horizontal dial but without handles.

There is plenty of evidence that iron was used for clock wheels and the introduction of guns advanced the state of ironwork. It seems that brass, which was relatively valuable, was reserved for expensive cases. Metal mining in Europe in the medieval period had been primitive, but with the advent of rock-blasting and water pumps, brass became cheaper than iron and its use spread rapidly through Europe in the seventeenth and eighteenth centuries. Nevertheless, making brass from its constituent metals, copper and zinc is a surprisingly difficult process.

One of the early metal clock types that appeared in the fourteenth century was also one of the first domestic clocks – a shelf clock that was similar to the later lantern clock, except that the pendulum was not incorporated into the clock until the mid-seventeenth century. There is some debate as to whether their name derives from their appearance or from the construction material – the old word latten, used to describe brass, is obviously similar to the English word ‘lantern’.

English brass lantern clock purporting to be by Joseph Knibb (1640–1711), but actually made in the mid-eighteenth century.

The Renaissance or rediscovery of the knowledge accumulated by the ancient civilizations created an economic revival that sponsored artisans and craft-work from the end of the fifteenth century. The better-quality metal clock cases were of cast brass or bronze and the process of gold-plating by the mercury fire method was developed.

The Renaissance period also saw the development of time-awareness and the consequent spread of clocks from religious and public buildings to private homes. Alloys of zinc, copper and tin became more readily available as the demand for clocks expanded. Clock cases of the Renaissance period were often painted with gold-like paint to mimic more valuable clock cases but at that time clocks remained the prerogative of the rich and powerful, both religious and secular.

The eighteenth-century industrial revolution made metals more easily available and, by the mid-1800s, mass production was bringing clocks and other manufactured items within the reach of the new waged classes of society. In Europe and America cheaper clocks were manufactured in a variety of cases, with companies launching illustrated catalogues to sell their wares. By that time the shift from hand-made to manufactured clocks was complete. The hand-made clocks of the eighteenth century gave way to cheaply made products but, regardless of any deterioration in quality, the market still demanded luxurious decoration, according to the taste and fashions of the day.

Illustration from the 1851 guide to the Great Exhibition in London. The accompanying text reads: ‘CLOCK, designed by Mr Woodington, the well-known sculptor; it is truly a fine work of art. Between four figures indicating the “Seasons” is one of “Time”, in the attitude of repose; above the dial is a bas-relief representing the winds and their various attributes and surmounting the top is Phoebus driving the chariot of the sun; the composition of this group is full of spirit, and the whole of the figures are extremely well modelled.’

THE MATERIALS

Copper Alloys

In its pure state, copper is a soft, red-coloured and ductile metal that is difficult to cast, but alloying it with tin, zinc or lead improves its casting characteristics. Brass and bronze both consist mainly of copper. The alloy of copper with about 12 per cent tin is bronze while alloys made from copper and about 37 per cent zinc are brass. (Early alloys used a wide range of mixes.) These two copper alloys are often confused and the metal called bronze in early clock cases may actually be the more common alloy, brass. Sometimes it is not that simple to specify a metal alloy because copper could be alloyed with almost any metal available.

Brass

Brass clock cases of the industrial period (1750– 1900) are usually of cast metal or a combination of cast and sheet metal, sometimes in several pieces that are soldered or screwed together. The front and sides of brass clock cases tend to be decorated with great detail, while the back is left plain.

The proportion of zinc affects the colour of brass. Gilding metal that contains less than 5 per cent zinc and 95 per cent copper is reddish-yellow in colour. Alloy containing 5–10 per cent zinc has very similar tone to bronze but, as the proportion of zinc increases, the reddish colour fades and the alloy appears more yellowish.

When brass contains 37 per cent or less zinc, it is metallurgically a simple single-phase alloy called alpha brass. This type of brass is easily cold-worked but is prone to hardening and requires periodic annealing during prolonged working. Most historic brasses are more or less alpha brass.

With a higher percentage of zinc the properties change. These more complex alloys (beta brasses) are suitable only for hot-working because they become more brittle.

The resistance of brass to corrosion is almost as good as that of pure copper, although alloying it with zinc does degrade it to some extent. As a casting material brass is cheaper than bronze, melts at less than 1000 degrees centigrade and has good casting properties.

Bronze

Bronze is a reddish-brown, easily ductile alloy of copper and tin. It has been a very popular material for statues and other ornaments.

When bronze contains 11 per cent or less tin, it is called alpha bronze. With a higher tin content, a brittle epsilon-phase is formed; bell metal, which is about 20 per cent tin, has special resonant properties to do with its brittleness but is prone to cracking. Cast bronze can have a higher percentage of tin without the formation of this brittle epsilon-phase.

Other than tin, bronze can be alloyed with several elements, including lead, nickel, bismuth, aluminium, phosphorus, manganese and arsenic. It is softer and easier to work than iron or steel, but at the same time it is about 10 per cent heavier than steel depending on the metal used to alloy copper.

Although bronze has been a very popular material for use in statues and jewellery for thousands of years, there are very few clock cases made from it. The most famous bronze clock cases are the so-called Orpheus clocks, of which there are only eleven known examples in the world. They were made in the sixteenth century in southern Germany and their rarity makes them extremely valuable. These remarkable table clocks, with horizontal dials and cast-metal cases, take their name from the ancient Greek mythological character Orpheus depicted in the friezes. They originate from the great clockmaking centres of Augsberg or Nuremberg but the maker or makers are unknown. The only clue lies in the initials ‘MTA’, marked on some of the clocks.

The author’s copy of the definitive work on Orpheus clocks, formerly presented to Hugh Tait of the British Museum in 1972 by Joseph Fremersdorf, who made his two Orpheus clocks available for research for the book.

Iron

There is evidence that, although the cases of some early portable clocks were made of wood, it was replaced by metal. It is reasonable to conclude that, since the clock wheels and frames were made of iron, the clockmakers would naturally extend their skills to making iron cases as an improvement on wood. Iron was a readily available and commonly worked metal, used in all sorts of artefacts in the medieval period, including weapons. It was only replaced by brass for making clock wheels and cases much later.

Wrought iron is an almost pure malleable form of the metal, which is easily worked and moderately resistant to corrosion.

Cast iron is a hard, brittle material that can break easily. It has a melting point of about 1200 degrees centigrade, 300 degrees lower than that of pure iron, and its casting characteristics are good. Any ferrous metal that contains over 2.5 per cent carbon is classified as cast iron. All of the carbon content is not chemically joined but occurs within the metal as free graphite or carbon particles.

Making cast-iron objects is difficult and in many cases the cast objects contain casting faults. Cast irons are classified by the colour of the fractured surface, which depends usually on the form in which the carbon has precipitated. When carbon is precipitated as cementite the fracture surface is white and the metal is called white cast iron. Graphite flakes in the metal cause the fractured metal to appear grey and then it is called grey cast iron.

Baroque-style Ansonia cast-iron case from 1880. The asymmetrical embellishments are typical for European baroque and these kind of clocks were popular in America and Europe at the time. The clock was not from the cheapest range and was aimed at the middle classes.

Cast iron has never been widely used in clock cases, with the exception of a type of mass-produced American clock developed in the 1880s. These were painted black and decorated with gilt brass or ornamental stone detailing.

Other Metals

Gilded base metals were popular from the late seventeenth to the early nineteenth century, with clock cases being manufactured from various metals and made to appear like gold with a very thin covering of gold leaf or plated gold. Zinc alloys became particularly popular in the late nineteenth century as cheap and easily workable materials. Casting moulds would last longer when used for zinc alloys because of its lower melting point. As the technologies for coating metals developed, most of the zinc alloy clock cases were successfully masked to resemble more valuable materials such as gilded brass or bronze.

In 1920, sculptors began to identify the disadvantages of cheap and easily workable base-metal alloys: large and heavy cast objects struggled to hold up their own weight and sometimes broke under the stress. There were problems with clock cases as well. Because of the casting properties and low melting point of zinc alloys, manufacturers found that they could be used to produce hollow figures and ornaments. Unfortunately, these cast-zinc features were fragile and prone to fracture when stress was applied.

Decorative zinc alloy parts covered with brass alloy are nevertheless fragile. Note the zinc exposed in the fracture surface.

FINISHES

Metal clock cases were finished in different ways, to alter their appearance and to improve their resistance to external factors such as handling, humidity and natural oxidation caused by air. The finish could be achieved by gilding, lacquering, painting, waxing or dyeing by oxidation with different chemicals. The character of the finish also sets some limits on restoration procedures.

Gilding

One of the more common finishes is the application of a thin layer of pure gold to the surface. Gilding was known in ancient times and relied then on the property of metallic gold, which allows it to be beaten to a very thin sheet. In fire-gilding, gold is dissolved in mercury and painted on to the surface. When the mercury is driven off by heat, the gold remains. The method was used until around 1840, when electrolytic processes started to be introduced for industrial gilding.

Gilded bronze ornament on a clock case. The gilding has been worn off at the highest points and has been patched with gold paint that can be seen as a different colour.

All that glitters is not gold and sometimes a clock case that seems to be gilded is not. For example, brass cases could also be cleaned by dipping in acid and lacquering with yellow-dyed lacquer. Few of these lacquered objects have survived because many of them were subsequently gilded. Synthetic gold alloys have been and still are used to give the impression of gilding at a lower cost. Various copper-rich brass alloys are used to make synthetic gold leaf. Occasionally, clock cases and parts were even painted with gold paint.

Lacquers and Patinas

The term lacquer is ambiguous and it can refer to the application of modern synthetic varnishes. However, in its proper use, it means a shellac coating that is usually applied to polished brass to prevent tarnishing.

Sometimes, solving the original coating (or lack of it) requires more than superficial investigation. For this completely matt, worn brass case, it seemed that it had not been originally polished, let alone lacquered. However, dismantling revealed a polished surface with partially yellowed lacquer under the hood ornament.

Cast zinc-alloy ornament on a clock case that has been chemically patinated to greenish-black.

Lacquering brass objects that were not previously lacquered is not advisable because it always affects the appearance of an object. It is, however, acceptable to re-lacquer the object if it has been originally lacquered and lacquer layers need to be replaced. It is difficult to apply a thin, even layer of lacquer but the preferred method is to pre-heat the metal surface to hand hot (without touching it) and then, with a soft camel-hair brush, lightly to apply a shellac polish that has been well diluted with alcohol.

In 1800 the French clock trade started to invest in different finishes on metal objects. Makers competed on the quality of their finish patinas and created new ways of producing them in different colours and shades. Pigments were usually mixed in different waxes and lacquers. A natural-looking patina was no longer the desired finish and a case could be finished to imitate more valuable materials such as marble, wood, gold or bronze. These finishes were done by galvanizing or distressing.

Finishing techniques developed in parallel to the rise in industrial manufacturing. While clock case parts had been previously finished by hand, different methods were innovated for immersing the parts in various solutions.

Paint

Paint finishes are most commonly found on nineteenth- and twentieth-century cast-iron cases for American clocks. They were painted black apparently, often straight on to the bare metal, to imitate the more expensive European black slate clocks. Traditionally, cast iron was painted with solvent-based or oil paints made from turpentine, linseed oil and, in many cases, lead and other noxious substances.

Wax Coatings

A wax coating provides a shield for a metal surface against deterioration caused by the environment and by handling. One suitable wax is microcrystalline wax but, in general, a wax should not contain any synthetic substances such as polyethylene, because such substances make it very difficult to remove. Natural oils and waxes such as beeswax and carnauba wax (a wax made from the palm leaf) react with metals and form organometallic complexes, which can also be difficult to remove later. Natural waxes are usually either acidic or turn acidic over time.

Wax mixed with solvents can be applied with a soft brush and then left to allow the solvent to evaporate. If the metal is not attached to wood, or another delicate material, it can be warmed after the wax is applied; the warmth will cause the wax to melt and flow, forming an even layer.

Applying microcrystalline wax with a soft brush on a gong.

Excess wax can be removed with soft, clean fabric while the metal is still warm. After the wax is completely dry it can be burnished with a lint-free cloth. As a surface coating, wax has the advantage that it protects the metal from staining and is soluble in white spirit so it can be removed easily. Waxes, especially passive waxes such as microcrystalline, do not affect lacquer or paint finishes but a preliminary test should be always done on an unnoticeable area before waxing the whole object.

IDENTIFICATION OF METALS AND METAL ALLOYS

Metal alloys used to cast clock cases are sometimes hard to identify, especially as all kinds of leftover scrap metal were melted and re-used. The term ‘pot metal’ came to be used in the twentieth century for zinc-based re-melted scrap. It is unworkable and difficult or impossible to solder or even glue.

The difficulty of identifying grey-coloured metal alloys without a specialist laboratory creates all sorts of challenges for restoration and conservation. That difficulty is compounded by the fact that many metal clock cases are painted, patinated, lacquered or plated with other metals. Lead and zinc look much alike but their characteristics are very different. Lead is a much softer and more malleable substance than zinc and can be scratched with a fingernail. Zinc is only slightly less dense than iron, but their corrosion products are very different – zinc forms a layer of whitish-grey powder of zinc oxide on the surface, while iron forms rust that can vary in colour from bright orange to almost black.

Indeed, the easiest way to identify a metal is to study its corrosion products (assuming that the object has formed them). These form when a metal reacts chemically with its environment, usually with oxygen in the presence of moisture. Ions formed in the oxidation process either dissolve or remain on the metal surface as solid oxide or part of the secondary salts.

Heavily corroded brass case; the iron pin that secures the back is also very rusted.

Normal oxidation should not be confused with damaging corrosion and cuprous metals such as brass and bronze form a dark brown oxidation layer of tarnish. This actually protects the metal underneath so it is either an attractive finish in its own right or just a cosmetic fault. When moisture and certain acidic contaminants are present, the surface of cuprous metals oxidizes to copper sulphate or carbonate. This corrosion appears as a light green or blueish-green matte surface encrustation.

When iron is in a passive state its corrosion product is reddish-brown or black and tightly attached on the metal surface. These layers of iron oxides and hydroxides can flake or break away with mechanical stress and expose the underlying iron surface, which leads to further corrosion.

Metal objects composed mostly of zinc react vigorously when in contact with other metals, especially if there is humidity involved. In conditions of high humidity zinc alloys corrode without the presence of any other metals and the corrosion appears as a greyish-white powder-like zinc oxide.

Handling metals without gloves will also corrode the surface because of the moisture, acidity and oils on the fingers. Eventually these contamination substances can cause a fingerprint to be etched into the metal surface.

Pitting is a phenomenon, which, as the name suggests, causes pits to form on the metal surface. This occurs when small areas of metal surface become reactive while surrounding metal stays non-reactive (passive). Only the active spots of metal corrode and leave small pits on the metal surface. It applies to most metals but especially to alloys or impure metals.

Active and passive corrosion seen inside the cast-iron case.

Heavy corrosion of zinc-alloy ornaments has left a zinc oxide residue on the painted cast-iron case.

Heavily corroded zinc-alloy ornaments that have been coated with brass. Pitting has permanently scarred the surface of the ornaments.

For more advanced identification, chemical analysis or an X-ray fluorescence spectrometer are required. Such analysis is a highly technical service provided by specialized laboratories.

STRUCTURE OF METAL CLOCK CASES

Brass and other alloy cases were usually casted from a few parts and in cheaper clocks the back was made from just a plain sheet of metal. Some cases were cast as top, centre and base parts, and joined together with threaded rods. In these cases, the back could also have some decoration.

Almost all iron clock cases are made up from separate cast parts, which were easy to assemble on a production line. A seemingly infinite variety of cast legs and other decorations and ornaments are fastened in place with threaded rods and nuts. The vast majority of these peripheral parts are cast iron and the American manufacturers seem to have developed some kind of flash-gilding process. The back panel is typically in cast iron although mild steel was used occasionally and the base-board, which often supported a gong, was usually of wood.

The top of the brass clock case fastens on its place with two threaded rods that are attached to the top and go through two lugs on the base. The whole item is tightened in place with nuts.

Cast-iron case partially dismantled. The wooden base and nuts holding the casted ornament parts can be seen when the back is removed.

Fractured arm of an ornament statue on a clock case. The material is very thin zinc alloy coated with brass.

As consumerism developed in the late nineteenth century, clock cases took on a rather ostentatious appearance, which apparently pleased the uncultured eye of the new waged classes. In these cheaper clock cases, the inspiration for decoration tended to be the neo-classical, rococo and Empire styles, with plentiful ornaments, architectural constructions and compositions of human-like figures in a variety of poses, from the classical to the rustic. Gold-like finishes are commonplace, although in many cases the finish was not of real gold. It was common to mix different styles very freely.

Cast figurines are usually attached to the case structure by threaded rods that go through the case and are secured from the inside with nuts. To minimize weight and save material, figurines are usually hollow, and sometimes made so thin that they are very fragile.

It is possible to find more than one metal alloy in the same clock case and different alloys have specific uses. Spelter, a zinc-rich alloy, has excellent casting properties so it tends to be used for all of the cast figures in any one clock case. Cast zinc or spelter is extremely fragile and, despite using a steel reinforcing armature, breakages are common – the arms and legs that fall off figures are notoriously difficult to re-attach. When restoring a complicated castspelter case, it should be thoroughly studied and the materials identified before taking any action.

CASTING METHODS

The simplest casting method is the so-called direct or lost-wax casting method. The model is made from wax and some wax rods are attached to its back and underside to form sprues, to release gasses and surplus metal. The mould is formed by covering the wax model with clay or plaster and, after drying, heating it to drive off the wax. With the mould empty of wax, the molten metal is poured in and, after cooling, the mould is broken away to reveal the casting with its attached sprues.

The lost-wax process is awkward and demands lots of time. If the casting is imperfect the process must be repeated, including making a new wax model. As a result, the idea of making an intermediate model was developed so that the original sculptor’s work would not be lost if the casting failed and, in addition, copies of the original could be made ad infinitum. It is likely that an intermediate model would have been used in the production of the Orpheus clocks in the 1500s because they are self-similar.

With industrialization and the increased availability of iron, skills in iron casting developed to a peak in the mid- to late 1800s. The faster, more efficient method of sand-casting suited industrial processes and factories. It was also suitable for multiple copies because it did not require the single original model or pattern to be destroyed in the process. The imprint of the original (the pattern) is made in specially mixed sand within a mould box. The model has to be designed so that it may be removed from the mould without breaking. When making more complicated shapes, such as box-shaped clock cases, several simple parts were cast for later assembly. The production of moulds became the trade of the pattern maker.

Most ornamental spelter figures are hollow, to save material and reduce weight. This could be achieved by pouring liquid wax in the mould and allowing it to set just partially. The rest of the wax was then poured off and the wax-lined mould was filled with plaster of Paris. The core was attached with metal rods, so it would not drop in the bottom of the mould when the wax was burned off. After that, the casting was performed just like in direct casting.

Marks of sprues on the back of the clock-case ornament.

This core-mould method could not be used with zinc as the casting metal, because of the heavy shrinkage as it cools and solidifies from the liquid. However, taking advantage of its low melting point, it was possible to make hollow zinc objects by pouring molten zinc into a hollow mould and then spinning it to coat the inside of the mould. Surplus zinc was poured off and the cast object allowed to cool down.

With the distribution of wealth through society, the demand for luxury items was met by industry and the manufacture of cheaper clocks commenced in earnest in the mid-1800s using new techniques and machinery.

CLEANING AND REMOVING ACTIVE CORROSION

Corrosion is an oxidation process in which the metal ions react in two different ways: either they dissolve or they stay on the metal surface in a solid oxide or salt form. (Salt in this sense means the chemical combination of a metal with that part of an acid; carbonates, nitrates and chlorides are salts when combined with metals.)

Metals can be corroded by grease, dust, traces of the dust of other metals and contaminants that are naturally present in human skin. These corrosion products are easy to remove by polishing, but, as a matter of conservation, it should be noted that a fraction of the metal is removed from a metal surface every time it is polished, eventually causing a loss of definition and detail.

When working with a metal surface, the first factor to establish is whether or not it was polished originally, bearing in mind that many objects might have been artificially patinated during the manufacturing stage. In the conservation or restoration of antique and cultural heritage objects, it is not appropriate to renovate or modernize by removing all the patina, which is part of its character and may be an indication of its age and history.

Treating Different Materials

If there is any kind of applied finish or protective coating, potential solvents should be tested on an unnoticeable area of the object. Most metal clock cases finished with lacquer or paint can be cleaned just with cotton wool or clean fabric dipped in water. However, this requires the coating that covers the surface to be undamaged and stable so the moisture will not migrate into the coating.

Grease can be removed by wiping with cotton wool dipped in a 1:1 solution of water and methanol, using a soft brush if necessary; a drop of ordinary detergent can be added to the solution. It is not unusual to find traces of polishing agent left by previous treatments. These usually appear as grey, white or green encrustations in the gaps, hollows and angles of the object. If these residues are not successfully removed by the cotton wool or the soft brush, a toothpick or nylon brush dipped in the solution may be used.

Plated zinc behaves very differently to brass and it reacts quite strongly in contact with other metals, resulting in a characteristic white powdery corrosion. Moisture left from fingerprints includes chloride ions, which react with zinc to form a hygroscopic salt, zinc chloride, which draws moisture from the atmosphere. This will etch into a polished surface, so cotton gloves are strongly recommended when handling any metal object.

When an object has been coated with a wax, lacquer or paint, it should be established whether or not the finish is original. Inevitably, experience and judgement will be needed for this; if the finish is not original, a decision must be made as to whether it is an essential feature of the object’s history. Sometimes, conserving such finishes is problematic or unsatisfactory, but on the other hand removing them can require the use of strong chemicals. The principles of conservation and restoration suggest minimal intervention as long as the object is otherwise stable.

Polishing

Polishing is a procedure that by its very nature removes particles from the surface of the metal. If it is necessary, the polishing process should be done by the most delicate means, for example, polishing with a paste made from precipitated lime and water with a soft piece of fabric. This will clean away surface deposits without removing metal.

In addition to hard abrasive materials, commercial polishing pastes quite often contain ammonia (which will dissolve copper), so metal polishes in cans and tubes should be used prudently.

Patinated metal surfaces require only periodic dust removal and no invasive cleaning methods should be used. If the patina is uneven, moisture-related corrosion or fingerprints may be involved. The surface may be polished but not with an abrasive metal polish and traces of bare metal should never be allowed to show through the patina.

Before polishing the whole object, the proposed method should be tested on an unnoticeable area. After polishing, the surface can be allowed to re-patinate naturally by air and should not be handled without gloves.

Although the overall impression is of baroque neoclassical, the decorative motifs are somewhat stylized.

A significant difference in appearance may be achieved only through thorough cleaning and light polishing.

Cast-iron case that has been corroded so heavily that the paint has flaked off. When rusting gets to this point there is nothing that can be done to save the original paint layer.

Rust Removal

Most cast-iron cases from the nineteenth and twentieth centuries are constructed from individual cast-iron plates fixed together with screws. Dampness is the primary cause of damage that can cause the metal of the case to corrode so heavily than it lifts the paint in flakes. The mechanism of spreading corrosion is a result of the expansion of rust from the original metallic iron. As the rust develops, it swells and lifts the paint surface from surrounding areas to allow the further migration of moisture.

It is not uncommon to find that the screws holding the cast-iron plates together have rusted solid and, in these circumstances, the first action is to try to loosen the corrosion with white spirit for two hours or more. It is not prudent to apply heat to cast iron because it is prone to cracking from thermal stresses. If white spirit fails to loosen the screw, the only option is to drill it out. Before making decisions about removing screws, the objective and necessity should always be weighed against the gain or loss.

First, the head of the screw is drilled off with a suitably sized drill bit so that the tip of the bit cuts down as far as the countersink, removing the fixture. After that, the protruding stub is removed by gripping with pliers and simply unscrewing. If that approach is not possible, the stub must be drilled down the axis and a stud extractor used. The tapered extractor grips the stud while turning anti-clockwise, so that it can be twisted out.

Unsuccessful attempt to remove the screw. A massive amount of corrosion has rusted it solid, which makes it necessary to take the case apart so that the corrosion can be removed everywhere and treated to protect the case afterwards.

Drilling the head of the screw off.

Removing the rest of the screw with pliers.

A stud-extractor set.

Once all the parts have been detached from each other the removal of the corrosion can start. Tannic acid is an excellent rust removal agent for treating different iron and steel objects. It is a complex organic acid that can be bought as a powder but exists naturally in plants, for example, in tea.

Lightly corroded objects can be cleaned by soaking in strong tea (1 litre of boiling water and two ordinary black teabags). After about twenty minutes the surface can be rubbed with fine wire wool. In addition to cleaning ferrous metals, tannic acid will form a ferric tannate layer that will provide continuing protection from corrosion. The tea treatment can be repeated as many times as needed – it will only thicken the ferric tannate layer – but other rust-removal treatments can be found that are more efficient and less time-consuming. Treatment with tea cannot be used if the affected parts have a paint covering. If the restoration plan is to remove damaged paint anyway, it should be entirely removed prior to any treatment with tea.

White spirit provides an easy and safe way to remove active corrosion. It is not a chemical conversion process but it penetrates the porous matrix of the rust, allowing it to disintegrate. A test should be done on a small area by dampening with white spirit and rubbing it gently with fine wire wool.

If these simple methods do not remove all the active corrosion, a gel may be made from 10 per cent citric acid solution and methyl hydroxyethyl cellulose (Tylose MH300), which is widely used in restoration and conservation as a gelling and thickening agent. The objective is to form an active cleaning gel. The advantage of using a gel instead of a liquid solution is that gel prevents the water from evaporating and holds the active agent in close contact with the target area. A gel is also easier to apply because it is not as runny. The duration of contact should be 15–20 minutes at first, increasing if necessary. If a longer exposure is required, it should be covered with cling film to prevent it drying out.

The treated surface can be rubbed with fine wire wool to remove the softened corrosion and most of the cleaning gel. Finally, the residues of gel should be rinsed off very carefully with clean water and the metal immediately dried with a hot air gun or hairdryer to prevent new corrosion forming. It is important to ensure that all traces of the treatment have been removed because any residual traces will promote new corrosion.

Heavily corroded cast-iron clock case before cleaning or removal of corrosion.

The same case after cleaning and treatment of the corrosion.

After removing active corrosion, the surface should be immediately covered with microcrystalline wax to protect it. Because of the uneven pitted surface structure of cast iron, it is easiest to apply wax with a brush.

Paint Removal

If the case is so heavily corroded that the paint, including any base coat, has largely come loose it should be removed. This has to be carefully considered before taking any action because the ideal is to preserve as much as possible of the original. In extreme circumstances, removing original paint cannot be avoided due to active corrosion that will continue eroding the material and eventually completely destroy it.

With painted cast-iron cases, a suitable paint stripper for metals should be used. Protective gloves and eye protection should always be used and the manufacturer’s instructions must be followed closely, particularly the recommendations about ventilation.

Manufacturers of paint strippers usually recommend that their products, whether solvent or water-based, should be painted on thickly and removed before drying. When all the paint and paint stripper have been removed, the case parts will be ready for a new base coat. This is a slow process because, after each application has dried, the surface is rubbed back with wet abrasive paper, gradually filling the depressions and pits. It can take many applications of the base coat but, eventually, the surface will be completely flat and even.

Base of the cast-iron case cleaned of all the old paint and corrosion. It has already started to corrode in places and, before starting to apply the base coat, all those corrosion products have to be removed.

Before painting the case, the suitability of the base coat for cast iron has to be checked but for the restorer the original types of paint are no longer available. Lead is hazardous to health and lead paint manufacture has been prohibited. Oil- or solvent-based paint is one good option for painting the cast-iron case but it has the disadvantage of slow drying. Modern replacements for traditional oil paints are alkyd water-based paints, which are available as aerosols in spray cans, giving a faster drying time and a more even finish (with a little practice).

The starting point of the process.

The whole case cleaned and re-painted and the ornaments cleaned and waxed with microcrystalline wax.

Treatments for Zinc Alloys

Zinc-alloy ornaments with different finishes are commonly seen on cast-iron clock cases, as well as on those made from other materials, including stone. In many cases they are plated with different metals such as gilding metal (brass), or they may be covered with gold leaf.

Brass-plated zinc-alloy ornaments that have formed both zinc and brass corrosion products.

Metal on the ornaments illustrated is easy to recognize as zinc or zinc-alloy from the distinctive white corrosion product and pitted surface caused by the corrosion. They were probably finished by electroplating with brass, although most of the finish is now gone. The bezel is pressed from thin brass sheet. All the parts were cleaned in an ultrasonic cleaning machine, using a solution of citric acid and detergent in water. After cleaning, the parts were rinsed well in warm water with a small amount of something alkaline added to it (a few drops of ammonia or some sodium bicarbonate) to stabilize the pH. After a final rinse with plain water the ornaments were rubbed with the finest grade of wire wool and immediately dried in hot air.

Zinc ornament cleaned and waxed, then fixed back to the re-painted cast-iron case.

This cleaning method removes grease and dirt from the surface, but not all of the oxidation. Conservators of old coins use mild acids, such as vinegar or even 10 per cent hydrochloric acid solution, to clean zinc coins, but acid treatment is not recommended because it preferentially dissolves zinc out of brass, leaving a coppery residue.

Surface corrosion can be removed from ornaments by rubbing with finest wire wool and white spirit. Afterwards, it is important to protect the surface because of the continuing propensity of zinc alloys to corrode. Microcrystalline wax is a stable, inert substance that is suitable for corrosion prevention.

RESTORATION

There are various ways to restore metal clock cases. In many cases the imagination and creativity of the restorer are put to the test, because the restoration should be carried out by following the ethics of conservation and restoration. Sometimes, unattached support can be considered if the weight-bearing structure has been damaged. One of the problems with this type of support is how to camouflage it so that the original appearance of the case is not altered.

Conserving Metal Clock Cases – Solders and Adhesives

If the metal parts have been bent, bending them back to shape should only be tried gently – with extreme care. Before attempting to bend a metal part it is a good idea to examine it for the presence of any cracks that will precipitate complete failure. If a significant degree of corrosion is present, bending the piece will usually lead to breakage because of the way micro-fissures propagate from corrosion sites.

Soldering with soft solder may seem to be the easiest way to repair cracks, but there are a few reasons why solder is not always a good idea:

•  The cause of the crack might be a faulty casting and heat applied to the area might exacerbate the problem.

•  Heat obviously affects different surface finishes and patination.

•  Flux used in the soldering process to help the molten solder run is difficult to remove completely and even a small trace of flux can damage the surface because it is corrosive.

•  Usually, cracks need reinforcements and adhesives to achieve a long-lasting result and there is less risk involved in this than in soldering.

•  Some metals, such as cast iron, are not suitable for soldering at all.

An ornamental horse leg that has been exposed to heat, which has caused the plating to discolour.

An unsuccessful attempt at soldering. The back of this plated zinc-alloy case is made from very thin sheets of metal. Impact has broken the back leg and someone has decided to repair it by soldering. The solder has failed to flow; it has stayed as big lumps and has not formed a durable seam.

Paraloid B72 resin granules.

To get the adhesive to form a lasting bond, the surfaces to be united should be clean and, particularly, free of oil contamination and corrosion. (However, if corrosion is tightly attached to the metal and is stable, it may not be necessary to remove it.)

Any adhesive used should be stable and should not react with the metal. Paraloid B48N is specially developed to be used with metals. Paraloid B72 is also suitable if it is mixed 1:1 with acetone. PVAC is not recommended to be used in the conservation of metals, including lead, copper or silver, because it promotes corrosion. Similar problems occur in copper metals exposed to epoxy resins that include amine hardeners. If this type of epoxy resin is used, the metal surface should be isolated with Paraloid B72.

Casting Missing Parts

It is possible to cast missing metal parts where tools and the necessary workspace are available. Where an identical part to the missing one remains, a mould can be taken from it and this is then used to cast a reconstruction. In this case the new part will be slightly smaller than the original due to the metal shrinking while cooling.

It is possible to cast metals by electronically layering them on a mould. Sometimes, replacement parts can be manufactured from other materials. Polyester resin and epoxy resin can be used when a replacement part does not have to support a great weight. Resins can be painted with metal powder paints to achieve an indistinguishable restoration. Alternatively, metal powder can be applied in a mould as an even layer before casting the resin. This method gives an especially convincing surface appearance. Resins are especially useful if large and heavy metal parts are missing. A mould can be attached in situ where the reconstructed part is going to be positioned. When casting a replacement piece in situ, it is important to isolate the original metal before casting. A structure may be supported with glass-fibre woven fabric.

Another choice as a casting medium is a lowmelting-point metal, such as alloys of tin and zinc.

Lost or Damaged Screws

The vast majority of metal clock cases are assembled from their individual components with screws. Steel screws can become damaged by corrosion, or they can break or lose the definition of the slot by which they are turned, especially if the screwdriver used is not exactly the right size in both width and thickness. Sometimes, screws are simply missing and need to be replaced.

Screws are relatively easy to make when all the right tools and materials are available. For replacement steel screws, an annealed silver steel (a high-carbon steel) is most suitable, because mild-steel screws will break. For brass screws, most brass round bar is made to be easily machinable by the addition of a small proportion of lead.

The diameter of the blank must be at least the same as that of the finished screw’s head. If the blank is supported only at one end (that is, in a chuck), it is important to determine how far from the chuck it is safe to cut for any slenderness.

The screw has broken and rusted solid in the case.

When working with a lathe, it is vital always to use eye protection, to secure all the parts before starting the lathe and always to use a spring-loaded safety chuck key. Manuals usually provide information about tip speeds for various cutter types and materials. Brass needs higher speeds than steel but, in all cases, good sharp tools are absolutely essential so it is vital to really understand how to grind cutters.

By the late nineteenth century, screw threads had been standardized, but in clock cases three different types of screw threads are found:

Working on a lathe.

Making the thread with the die.

Metric (M), British Standard Whitworth (BSW) and British Association (BA). If it is not known which type of screws the clock case has, it is easy to test this with a thread gauge or otherwise by very gently trying different taps in the internal thread where the screw is missing.

The tap that screws into the thread is the correct thread type and the matching size can be chosen from the corresponding die. Thread size charts can be found online – providing the exact measurements, including the diameter of the screw blank – and one of these should be consulted before starting to cut the thread.

When the screw blank has been turned to the correct diameter, it should be slightly reduced in diameter at the end to make it easier to start the die.

With the screw blank still in the lathe, the threading is done by turning the chuck by hand against the die, holding the die square and true. For small screws, the lathe should not be turned on: it is possible to cut a thread using a lathe but that would require a different set-up. A good rule of thumb when cutting the thread is to cut three half-turns, then go back one. This allows the chips to clear the cutter; otherwise they will pile up in the die and eventually break one or more of its teeth, or damage the thread.

As the die approaches the screw-head, it is better to stop a bit too early than to tighten the die against the head because this may also break the teeth of the die and the brand-new thread of the screw.

When the thread is finished, the die can be spun off and the rod with a partly finished screw taken off from the lathe and put in a bench vice. Decide how thick to make the screw-head by following the pattern of the originals and cut it off with a junior hacksaw. The slot can be cut with a hacksaw or with a very thin file. Steel screws can now be blued by polishing and then heating in a flame. Brass screws require only a polish before they are ready for use.

The thread is cut ready and the screw can now be sawn off from the rod.

Sometimes, the clock-case parts are fastened together with a nut. These can also go missing or the internal thread can break. Replacements can be made by drilling a suitable hole in a steel sheet (check the correct drill-bit size from the thread chart), but usually the easy way is to drill and tap in the lathe and then file the flats, still in the lathe.

Comparing the original screw and the new one made to replace the missing item. The replacement still has to be polished and blued.

Drilled holes on a sheet of steel and starting to cut the thread with a tapered tap.

The thread is cut and the nut blank is ready to be sawn off and to have the final touches put to it.

In thread sets there are two types of taps: tapered and cylindrical or plug. When making nuts the tapered one should be used. Cylindrical or plug taps are used only when the hole is blind and threaded all the way to the bottom. Use the same action for the nut as the screw: three half-turns forward and one back to remove the chips.

CASE STUDY: AMERICAN ANSONIA CAST-IRON CLOCK CASE

This American clock case is a marvellous example of the results of enthusiastic but largely misguided repair methods that turn up in our workshop occasionally. The case is painted cast iron with four columns on the front. Although being very dirty, the paint layer seems to be in good condition. Some active corrosion is visible inside the case where there is no paint to protect the iron. The four columns are plated, so there is no corrosion on them.

The columns are hollow tubes that are clenched in place with top and base parts of the case. Inside the columns runs a threaded rod that keeps the columns located. It was very apparent during dismantling that the ornaments are coated zinc alloy. A rosette at the top is attached with a threaded rod and nut.

The surprise lay inside the case when we uncovered the nature of the previous repair work: a great amount of a black rubbery substance had been used in an attempt to join the cast-iron parts together. It was probably some kind of plumber’s silicone mastic sealant and it seemed to be holding the base and the main sections of the case together. Due to the natural elasticity of the substance, the case parts were not completely solid and were rubbing against each other when moved around. This had also set up stresses in the cast-iron panels, rendering them very vulnerable to further breakages.

Starting point. At first glance the case seems to be in a pretty good shape.

On further study, it becomes apparent that one of the corners has a thin crack.

The columns dismantled from the rod that is attached to the top of the case. All the parts are tightened in place with one single nut.

The bottom of the columns and the nut holding the pieces in place.

Obviously, the silicone mastic patching had to be removed to allow a proper restoration. First, it is not fulfilling its intended function, so it will not be preserving the original piece in a satisfactory way; and second, it is not a way to respect an object of cultural heritage, although it has become part of the object’s personal history. (Nevertheless, we never make judgements about the quality of others’ work; we only deal with the extant facts, the present situation and the integrity of the object in our care.)

The objective of removing the previous repair work requires the removal of some stubborn silicone mastic.

The silicone patching inside the case.

The sealant was very tightly attached to the grainy cast-iron surface, but when it finally started to lift off it did not leave any residue behind. When the adhesive was removed from the case, the reason for its presence became clear: both of the iron lugs by which the case parts are fixed together were broken and pieces were missing. One of the lugs had broken part of the case wall with it.

One of the corners broken off.

Broken cast-iron lug.

Because cast iron cannot be soldered, and pinning would crucially affect the appearance of the case, the suitable method of restoring the case was to use an appropriate adhesive. This application is demanding of an adhesive because it has to be strong enough to hold the weight of the top of the case while remaining chemically inert relative to the cast iron. In this case, Paraloid resin was not chosen for the job because it might not form a sufficiently strong adherence.

When choosing adhesive it is always important to pick one that is suitable for restored material, so that it will not cause further damage. In this case an epoxy adhesive, Araldite Metal, was used, because it was the strongest suitable adhesive. Equal portions were mixed together and a thin layer of adhesive spread on both break surfaces. They were tightly fitted together and clamped to ensure a tight plain joint. (Any glue line should be thin enough to bond the surfaces without acting as a space-filling material.)

The glued repair and a washer with a screw.

When the adhesive was completely dry, excess adhesive was removed carefully from the surface by cutting it flat with a scalpel and rubbing back with 1200-grit abrasive paper. After that, a thin layer of alkyd paint was added to retouch the seam.

Although the lugs were both broken, it would not serve the purpose to make new pieces and glue them in place. A much easier way was to use screws and nuts with large washers that would hold the rest of the lugs firmly in place.

The cleaned, restored case.

Chapter 9

Finding a Clock Case to Restore

As professionals in the horological sector we have a plentiful supply of clocks in our waiting room, a significant proportion of them recently acquired by clients. Some have been bought by astute investors (antique clocks are exempt from Capital Gains Tax in UK, so they can represent a wise investment), some are planned purchases and some are the result of an impulse buy. We also trawl the market for worthy clocks as investment opportunities, either for ourselves or on behalf of clients.

This type of clock case can usually be bought very cheaply (for as little as £10). There is no movement, but they are relatively easy to find, although the hole spacings in the dial will align to only one particular make. Beware, there were plenty of German copies of these clocks.

A somewhat naive attempt at dial re-painting but the case is structurally sound (with a few losses).

In certain regions, periodically painting furniture was commonplace. It may have served to protect the veneers.

Where to start? Record everything, including any tests to establish the types of paint.

Lots of people ask for advice about where they might find a clock case for restoration. The reply usually revolves around a number of issues: budget, the availability of facilities such as a workspace, the experience of the restorer, and whether he wants to be involved in repairing a clock movement. It would be very unusual to find the movement inside a broken-down clock case in anything like good order and, except for certain American clocks, buying an empty case on the off-chance of adding a clock movement at a later stage is just not a realistic proposition. Restoring clock cases is likely to be an adjunct to the mechanical skills that a clock-mender develops.

Brass inlays in a dark veneer that could be rosewood. As a bonus, the case contains an original bell, hands, key and so on.

Clock-case restoration is one of many specialized sectors within the much wider field of antique restoration and conservation and, as in furniture restoration, there are many areas for narrower specialization. The fact that clock cases are poorly catered for by clock interest groups is well known and clock-case restorers cannot expect the same level of support enjoyed by the mainstream of clock-repairers and restorers.

A FEW RULES

Rule Number 1

Buy a clock because it is good quality, not because it is cheap.

Sometimes, clocks with damaged cases just arrive at our workshop but that is because we are well established and well known in the horological sector. For most amateur or hobby clock-case restorers, it is a matter of hunting around to find something that is worthy of restoration while still within the available budget and not unduly challenging.

Rule Number 2

Be prepared to make mistakes in buying. It is the best way to learn.

Arthur Negus, the well-known expert in antique furniture, once said that he had never made any mistakes buying furniture, although he had often bought valuable experience. Whether it proves to be a good clock or a bad one, the experience will be useful. If anyone in the antiques trade claims never to have made a mistake, it is probably a bad idea to buy anything from them.

Self-teaching about clock-case restoration really means trying out the techniques on clock cases that are of no particular value. Unfortunately, acquiring the skills and experience inevitably entails a certain amount of getting it wrong: that is the way to learn, but it is obviously a good idea to start with a project that is not overly demanding and preferably not something that might be classified as horological heritage.

The beginner is spoilt for choice with so many clocks in need of restoration these days, but finding something suitable and worthwhile as a learning project takes a bit of thought.

Rule Number 3

Find a clock project that will be rewarding without being over-ambitious.

Finding the right clock is about a number of factors:

1.  Know what you are capable of, in terms of available resources, experience and skills.

2.  Understand something about the history of clocks in society and be able to tell the difference between early hand-made and later factory-made.

3.  Know what materials are involved and how easy or difficult it might be to find suitable sources for making replacement parts.

4.  Although a clock-case restoration does not have to be a commercial enterprise, it is a good idea to be able to estimate market values in as-found and restored condition.

A mid-twentieth-century replacement case for an early nineteenth-century Irish provincial longcase clock. The style does not suit the clock and no amount of restoration will change that. The only answer is a complete new case. (James Rooney)

A nice late eighteenth-century Cornish longcase clock in an auction sale. It is unusual, being made of pine, but sadly it has been stripped of its original paint.

Available Resources – Workspace and Tools

A longcase clock is probably not a suitable kitchen-table project but there are plenty of clocks that are. Clocks that can be stored away when not being worked on and which do not require workshop tools can be restored as indoor hobby projects.

‘Workshop tools’ are those that are too big to be used in the normal home. The band-saw and other electric saws, the lathe, and high-speed woodworking tools such as routers all create wood dust and are best used only in a purpose-equipped workshop, along with a proper work bench and plenty of storage space for all the hand tools.

A proper workspace will have plenty of storage space for stocks of wood and scrap furniture. Many different types of wood have been used in making clock cases and, for the purposes of appropriate restoration, it is necessary to have a supply of those woods, either as new stock wood or scrap pieces, or even as either new or salvaged veneers.

Any clock case can be made using only hand tools but it would be very difficult or nearly impossible to make a case using only power tools or woodworking machinery. Restoration and conservation projects are best undertaken using the same working methods and tools as those used to make the piece originally.

The greatest impediment to good woodwork is blunt tools. The ostensibly simple act of sharpening a wood chisel actually takes a lot of practice, sometimes over a number of weeks. In addition, there are plane blades, gouges, drills and so on, none of which work satisfactorily if they are not surgically sharp.

It is as well to accept that limitation (which will just be temporary) when choosing a suitable clock because, if woodwork is a significant part of the project, blunt tools are likely to give rise to frustration and dissatisfaction.

Available Resources – Skills and Experience

Much of the satisfaction for the hobbyist is in breaking new ground and expanding his range of skills and experience. Over the years, and with each new project, any restorer expands towards higher levels of competence in all the various aspects of his work, including the formal approach to restoration and conservation. In following a logical pathway from straightforward basic projects to the most difficult, it is always tempting to embark on something that is just too ambitious. Why not? Most people work well under pressure but the frustration of not being able to do a neat professional job can potentially have a long-term negative effect.

The situation for a professional restorer is not so different because, although he has little choice about the level of difficulty involved in each new project that arrives, they are all different and will present a unique set of challenges. The restorer or conservator regularly contemplates the unanticipated and, for the professional conservator, recognizing and dealing with new circumstances is normally part of the formal written conservation plan. Restorers are traditionally less inclined to formal documentation but, if they are honest, will usually admit to a whole series of unanticipated upsets and mishaps. However, restoration should not be seen as a downgraded form of conservation, just because it prioritizes continuing use over preservation of an object of cultural heritage. A restoration project should be researched and documented and the work recorded in the same way as any conservation activity.

Understanding the History

In general, old clocks worthy of restoration tend to be those made before the introduction of mass production, which began in the middle of the nineteenth century. Because of the structure of society and the lack of a need for time awareness, fewer clocks were produced for sale, but they were hand-made for the wealthy, hence they tend to have intrinsic value of rarity and quality of workmanship.

There is no doubt that maker, rarity and quality are always features that will give a clock value and it is those characteristics that the hobbyist should be able to recognize. Unfortunately, those characteristics make good clocks collectable and hard to find. It can be like looking for a needle in a haystack because there are so many mediocre and low-value clocks. However, as clocks are disappearing very fast for lack of skilled people to restore them, the scope for restoration has gradually expanded to include clocks made in the twentieth century.

Restoration and conservation of clocks does not mean doing only the tangible work needed to repair or stabilize. It also means doing the background research and generally treating the clock as an object of cultural heritage. Conservators and restorers need to have a detailed understanding of the evolution of clocks through history and to be able to make judgements about both age and social status. In the antique furniture trade, the formal assessment of a piece of antique furniture must include information about status or social context, because that is one of the strong influences on value. The most valid question that an owner or restorer can answer about a piece of furniture or a clock is not necessarily ‘When was it made?’ but ‘Who was it made for?’

The website clockswatches. co.uk is one of several useful sources of information.

Dozens of books have been produced about the history and development of clocks and most have something to offer. The Anglo-Irish writer Jonathon Swift (1667–1745) advised parents to let their children read anything because they will always find better later. The same applies to clock historians and clock-case restorers. Do read anything available and use the internet for research, including the hundreds of online auction catalogues that are now available.

One of several online auction sites. This one represents hundreds of auction houses and allows the user to do a search of all the current catalogues in a single action.

There are organizations online representing hundreds of auctioneers and a single search term can yield huge numbers of clocks presented in auctions. In a simple experiment, an automated search on term ‘clock’ entered into the website the-saleroom.com yielded 1,667 clocks across fourteen countries from Austria to the USA. The auctioneers’ guide prices ranged from £90,000 to £110,000 for a Fabergé desk clock down to £10 for a 1930s mantle clock. The value of online auction catalogues to an aspiring horologist or clock restorer is in both the descriptions (whether correct or not) of clocks and the estimates of current market value.

Knowing What Materials are Involved

Some woods are now extinct or unobtainable, other than as scrap from discarded antique furniture. Even woods such as European walnut are difficult to find and can cost up to €100 per cubic foot. Exotic veneers can be very expensive if bought from a specialist supplier, and buying scrap furniture to salvage veneers can be an expensive and time-consuming exercise, with no guarantee of success. Missing marquetry, lines and inlays are difficult but not impossible to replicate but they are often found in scrap antiques. It is obviously never safe to destroy antique furniture in the interests of restoring an antique clock case. It should be an absolute rule to make sure that the scrapped furniture itself is not a candidate for restoration or conservation.

Non-wood cases can be extremely problematic and, although it is relatively easy to find the types of dark grey calcareous slates used in late nineteenth-century clocks, the marbles are very difficult to match. The quarries that produced ornamental marbles in Europe were mostly abandoned decades ago, and those types of stone are scarce as scrap. There are, however, plenty of hopelessly broken stone clock cases waiting to be dumped.

Cast iron was used extensively in the late nineteenth century, especially in American mantle clocks (many of the so-called ‘black clocks’, which were actually made of cast iron in imitation of slate or black marble). It is a difficult material to work – brittle and prone to corrosion – and, worse, notoriously difficult to repair by welding because of the thermal stresses induced.

Discarded stone cases might not be worth restoring but they are a valuable source of materials.

Market Value and the Concept of Economically Repairable

The value of clocks varies widely – from as little as £1 to over £1,000,000 in a very few cases – and the costs of professional restoration or conservation tend to be related to that value, because a valuable clock justifies the additional expense of more careful examination, test work and documentation. Economically repairable is a simple arithmetical test based on uncertain notions of value or worth but essentially it assumes that the value of a clock will be enhanced by restoration work (which is not guaranteed), and that that increase in asset value will exceed the cost of restoration. Otherwise, there is no net value gain for the clock owner and only the professional restorer is better off.

Costs of Restoration

The cost of materials for a clock-case restoration can vary enormously and estimating those costs depends on being able to identify accurately what material needs to be used and how much of it is required. All woodwork carries a wastage factor; as carpenters used to say, ‘It’s not the wood you use, it’s the wood you don’t use.’ To the costs of materials should be added the cost of any special tools that a project may require.

A Jerome & Company 8-day ogee made in the early 1850s. Despite a dirty appearance, it is in unusually good condition. Nevertheless, case restoration is likely to be around £200. The market value of the complete restored clock might be £500 to £700.

A typical major case restoration for a long-case clock could cost several hundred pounds in materials, while the materials needed for the restoration of smaller and later shelf or mantle clocks rarely exceeds about £20. Typically costs of expensive items including hinges, locks and other metalware can be significant, as well as gold leaf and Georgian blown glass for replacements in pre-Victorian clocks.

To take an example, an American 8-day clock in poor condition can be picked up in an auction or car-boot sale for just a few pounds. The costs for professional overhaul of the movement and restoration of the case might be £400 and £250 respectively. In a restored and overhauled condition the same clock might have a market value of about £700 so restoration is just about justified, albeit marginally.

An American shelf clock in the Gothic style with a reverse-painted glass panel.

Very thin veneers are susceptible to lifting in a damp environment. Successful replacement is possible with the right materials and method.

Small chips of softwood missing from the top edge of the pediment are not insignificant. Without reinstating the profile, the replacement veneer will not lie correctly.

Ostensibly, with a cost for materials of typically £50, DIY restoration for that class of clock looks like a better proposition because it does without the labour cost. However, that is not the full story and for the hobbyist the time spent on a clock restoration, although not accounted for, still has a cost in the domestic context. It is just as well to spend the time wisely for the best possible return in satisfaction, gained experience, technical challenges overcome or even added monetary value.

Any potential restoration project can be assessed in terms of present value but the clock market, like any other aspect of the antiques trade, is somewhat volatile and unpredictable. The price of clocks tends to reflect prevailing economic conditions so that, at times of full employment and expansion, clocks increase in value, falling again during periods of recession. Consequently, the concept of economically repairable is not clear-cut.

WHERE TO LOOK FOR CLOCKS FOR RESTORATION

Junk Shops

The contents of houses often end up in high-street shops that offer a wide range of domestic items such as furniture, appliances and occasionally antiques, including clocks. It is often a matter of being in the right place at the right time.

Internet Selling Sites

Internet selling sites such as eBay, Donedeal, and so on, provide a platform for individuals and companies to sell all sorts of things, either by direct sale or by auction. Quite often, the seller will have a grossly inflated notion of the value of the items he is offering for sale but, in an open competitive auction, it is always the market that dictates the true value (on that day). Buying anything blind is risky even with good-quality pictures and it is prudent to check the selling conditions carefully.

Antique Shops and Emporia

The traditional high-street antique shops are disappearing and the trend is now for groups of sellers to combine in larger premises, creating a co-operative antiques emporium. Unlike the traditional antique shop, which was run by someone with detailed knowledge of what he was selling, pitches in a collective emporium are often operated by less knowledgeable traders who may be far less likely to spot a treasure than the clock enthusiast. Because clocks are mostly sold on their outward appearance, most antique traders recognize that a damaged or distressed clock case seriously deflates the value of the clock and consequently they are quite often willing to sell at a low price. A certain amount of haggling is always worthwhile.

The antique fair is an extension of the cooperative antique emporium concept, except that the owner of the antiques presented on each stand is more likely to be present.

This adapted longcase was acquired from a clock dealer. The top of the back-board had been removed and the hood discarded when it was converted to a drinks cabinet.

Clock Shops

Clock repairers are rarely willing to undertake serious clock-case restoration and in fact the British Horological Institute advises them to avoid the work. Most well-established clock repairers have an accumulation of empty cases and clocks that are beyond economic repair.

The unusually good quality of the workmanship suggests that this clock case is worth restoring. Because of the shape of the door, the clock must have had a square dial; the style suggests late eighteenth century.

Car-Boot Sales

The universal rule applies equally to sellers at car-boot sales and antique auctions. Because of the wide range of articles that the seller offers, he cannot be an expert in everything and from time to time good clocks will appear at car-boot sales. The trick is usually to arrive early and move fast.

Independent traders carry out house clearances and act as a bridge between supply and demand.

Antique Auctions

There are two sorts of antique auction houses: the small operators, which take all classes of domestic contents, glass, ceramics, furniture, art, silver, clocks and so on, and the large auction houses with specialists in each field.

There is less chance of spotting an unnoticed treasure in the bigger auctions but in the small country auction the general auctioneer is less likely to be particularly knowledgeable on the subject of clocks. While he must spend time and effort describing each one of hundreds of lots, the keen amateur horologist can concentrate on just a few clocks, examining them in detail and estimating the difficulties and costs entailed in restoration.

The auctioneer makes his money by charging a percentage – typically 15–20 per cent, and sometimes more – to both the seller and the buyer. To justify that charge, he provides the auction venue and organization, and for each auction he produces the catalogue of lots. He will also accept instructions from absentee bidders, and bid on their behalf.

For the novice bidder, the auction room is quite an intimidating environment, but there are a few basic rules to follow:

•  Go to the public viewing and examine any lot that you think might be suitable. Make up your own mind regardless of the description in the catalogue and do not just look at the positive aspects. Think about the faults as well.

•  Decide on how much you are willing to pay; most auctioneers add an estimate or guide price to the lot description in the catalogue, based on the auctioneer’s interpretation of the lot and his knowledge of the market.

•  Once you have decided on your maximum bid, stick to it; there will always be another clock in another auction if you miss this one.

A typical provincial auctioneer’s website. Well-established and experienced auctioneers tend to be helpful, often dealing with their clients on a personal level.

An unusual English fusée bought in a small country auction for £85 plus 15 per cent commission. The case has a few faults but the dial is interesting because of the painted watermill scene, which utilizes a moving watermill on an extension of the escape wheel arbor. Unfortunately, the clockwise rotation of the waterwheel appears to push the water uphill!

Check the back carefully to make sure it is genuine and original to the clock.

There are various bidding strategies but, as long as you catch the auctioneer’s attention with your initial bid, he will watch out for further bids from you. Individual bidding strategies vary between vigorously waving the catalogue and an almost imperceptible nod or wink. Although detailed information on the psychology of auctions and bidding is beyond the scope of this book, there are a few points worth mentioning:

•  The estimate tends to anchor the bidder’s perception of the value of a lot. In other words, the bidder is inclined towards the opinion that exceeding the guide price would be imprudent.

•  The behaviour of one bidder is influenced by the behaviour of others.

•  An unduly low estimate or starting bid tends to lead to a higher selling price.

•  A very late initial bid (a new bidder just before the hammer) can deflate the opposing bidders.

•  Overtly assertive bidding can sometimes deflate the opposition.

•  A bidder who hesitates is suggesting that he has reached or exceeded his limit.

•  An auction catalogue is not a shopping list so do not decide to buy something regardless; bid only to a defined limit.

The Grapevine

If you can develop contacts in or around the clock trade you may find that clocks will start to appear out of the blue. Most people would prefer to see a broken-down clock go to a good home rather than the waste disposal facility.

Legal Points

There are a few things that are worth knowing in terms of the legal position:

•  Depending on the country and the auction, the seller might be entitled to bid on his own lot but it is illegal for the seller to use a third party (a ‘shill’) to generate interest by bidding on the seller’s instructions. Shilling happens sometimes in online bidding where the seller uses multiple identities or family members to increase the bids.

•  It is illegal for a group of bidders to conspire together to form a ‘ring’ so that only one of them bids on a lot. That would be a conspiracy to defraud and it happens both in a pre-meditated way and inadvertently when one bidder chivalrously holds off in favour of an opposing bidder.

•  The term ‘Reserve’ means that certain rights have been reserved including the right to withdraw a lot from sale, whether or not the reserve bid has been made.

•  There is no such thing as a preservation order on privately owned antiques. An individual who owns an antique clock is entitled do with it as he likes.

•  Sale of goods and services legislation does not offer the same protection to the buyer of faulty antique furniture and clocks as it does to the buyer of new items.

•  Most auctioneers rely on the concept of caveat emptor, or ‘let the buyer beware’. The small print in most auction catalogues will include something along the lines of, ‘We have endeavoured to describe everything accurately but if we haven’t it’s not our responsibility.’

•  For the purpose of taxation on any profit, it is worth knowing that (in the UK at least) antique clocks are classed as wasting assets and specifically exempt from Capital Gains Tax. That mean that a private collector may keep any profit that he makes from selling an antique clock. (The tax implications of selling other pieces of artwork are different and it is worth checking with a professional tax advisor if you are not sure.)

A replacement hood made for a round-dial longcase clock that was found in a rubbish skip.

Appendix

Guidelines for Restoring and Conserving Horological Objects

The purpose of this appendix is to gather together and present our ethical rules about the conservation and restoration of clocks and clock cases. Such guidelines apply equally to work with objects of horological history as to work on any object of cultural heritage. Every piece needs an individual plan of action and making the necessary decisions is never straightforward. The conflicts are often greater for clocks and, because compromise is part of deciding how to do the work, ‘compromise’ can be a problematic word to use; there must be limits to the degree to which the ideal can be compromised.

RESPONSIBILITIES TO THE OBJECT

It is important to respect all aspects of a clock: the aesthetic, cultural, mechanical and historical. About a hundred years ago, F. Garrard wrote in Clock Repairing and Making that an original verge escapement of the kind found in very early clocks could be replaced with a modern anchor escapement. It was a different, non-conservation way of thinking that was of its time.

There are a number of guidelines to follow:

•--Decisions about restoration should not be influenced by profit motives and the value of the object should not alter ethical decision-making about restoration or conservation work.

•--The same standards should apply to every object.

•--Exceptions to the rules can sometimes be related to the condition of the object and every clock must always be considered individually.

•--Decisions should never be made lightly; as a rule of thumb, do not do or recommend anything you are not completely sure about.

•--When you are working on an antique clock case (or any antique object), aim to do it in a way that the original maker would approve of.

•--There is no shame in asking for professional assistance.

•--One of the principles of restoring and conserving is always to avoid doing anything irreversible. This means not using methods or materials that cannot be removed, so that the original will not be permanently changed. When it comes to clock movements, however, this principle is clearly incompatible. As mechanical devices they wear out and it is natural that the worn parts will need to be replaced to prevent further damage.

•--When making decisions about how to proceed with work the restorer or conservator should carefully consider what methods and materials to use; wherever possible, the materials should be comparable with the original.

•--It should never be the intent to make the restored or replaced parts invisible to the professional eye. Using the clock movement as an example, the restored parts should not be masked in the original; an experienced eye should be able to tell what restoration work has been done in the past. Although it was once common practice among clock menders, engraving initials and the date of repair on a clock is not appropriate.

•--Physical restoration work is not the sole aspect of caring for and preserving a clock; it should also be stabilized to prevent any further damage. This means identifying the causes of, and stopping, deterioration to protect what remains of the original.

•--No attempt should be made to improve the original. Some cosmetic wear and tear is acceptable if it does not affect the preservation or the functioning of the clock.

•--The person performing the conservation or restoration has a responsibility to protect the object from further damage. This duty can be discharged by arranging a suitable workplace, safe methods and an environment where the requirements of the object (stability) are recognized.

INVESTIGATING AND RECORDING

Because of the cultural and historical value of clocks, they should be thoroughly examined and documented by way of photographs, written notes and any other means necessary (including dimensional drawings and diagrams). The recording and documenting should be done prior to making a restoration or conservation plan.

The preparation of a Condition Report is a standard procedure among professionals. It should always be done, regardless of amateur or professional status, if only because it adds to the heritage (and monetary) value of the clock.

The Condition Report should contain at least the following: the date, the name of the restorer, the results of research about historical and social context, photographs and written description of the materials used, structure and production methods, measurements, deteriorations and previous repairs or modifications (these are usually easiest to mark on a pictorial document with a written description to clarify it), and observations and analyses of materials present.

The various treatment options should also be documented, with supporting arguments for or against and an assessment of likely outcomes. When the options have been considered by the owner or guardian, a step-by-step action plan should be formulated. It is in the interests of the restorer to have a defined plan of work, which should contain detail of materials and techniques. With clocks it is also important to write down instructions for the maintenance of the clock in question (such as winding, setting time and beat, how to move the clock around and how often it will require inspection and service).

A copy of all documentation should be kept with the object and it will become the responsibility of the owner and possible seller to preserve this. The restorer has a responsibility to make the owner aware of the significance of these documents.

RESPONSIBILITIES TO THE CLIENT

If the restoration or conservation work is being done for a third party, the restorer should acknowledge his responsibilities towards the owner of the clock, by showing due care to the object, and by providing information about costs and so on. The restoration or conservation plan is a significant document because it is the basis of the agreement between the owner of an object and the restorer. Before any work is started, the client should be provided with an estimate of the total fees, broken down in terms of time, material costs and any possible sub-contractors’ expenses.

Index

acanthus 46

adhesives see glues

alarm clocks 21

alkanet 28

amateur restorer/conservator 17

Art Deco clocks 145

Art Nouveau style 150

ash 31

baluster 42

balusters, half-round, making 60

barley sugar twists 61

beech 31

black slate 163

brass 169

bronze 170

carving 42 46 118

American drop-dial clocks 47

incised 49

cast iron 187

cast spelter 176

casting methods 177

casting 184

clock movement removal 156

clock ownership 9

column 42

classical 60

entatsis 61

condition report 102

conservation

clocks, a special case 15

definition 14

copper alloys 169

cornice 42

corrosion cleaning 177

cutting gauge 92

design

CAD 68

detail 69

factors in 12

research 68

working drawings 67

dial (origins) 12

distortions in timber 35

dovetail tie 108

Dragon’s Blood 28

drop-dial clocks 127

dust bead 111

English bracket clocks 139

English fusée clocks 123

English shelf clocks 142

European shelf clocks 141

Fibonacci 45

finial 42

French polishing 58

fretwork 120

gilding 54, 106, 166

gingerbread clocks 129

glue

blocks 110

collagen (scotch) 49

hot melt adesives 50

solvent-based 51

water-based 51

gold leaf 54

golden section 46

horological heritage 19

inlays 53

intaglio 44, 162

intarsia 44

iron 170

kingwood 34

limestone 151, 156

breccia breche 152

longcase

base 71, 74

escutcheon 96

finials 86

hinges 94

hood 71, 81, 116

hood door 88

hood door hinges 90

hood frame 114

lock 96

seat-board 81

seat-board 84

trunk 72, 107

trunk door 70, 91

mahogany

Honduras 33

substitutes 33

Swietana Mahogani 33

marble 149, 150

Connemara green 151

marine chronometer cases 148

marquetry 44

metal clock cases

conserving 183

corrosion in 175

finishes 172

gilding 169

gindling 172

history of 168

laquers and patinas 172

paint 173

paint removal 181

polishing 178

restoration 183

rust removal 179

structure 175

wax coatings 173

moulding 44, 76, 79, 117, 136

Napoleon’s hat clocks 147

oak 26

embossed 28

ogee clocks 10, 126

over-sailing 86

painted grain effect 54, 55

paraloid 184

parquetry 45

pediment 45

pillar 42

plywood 145

polishing shellac 58

postman’s clock 128

potassium permanganate 28, 98

preservation 14

railway clocks 123

rebate planes 93

restoration

formal ethical 15

case study 100

definition 14

plan 18, 103

re-veneering 118

rosewood 34

rusted screws 180

satinwood 34

screws, making 185

seat-board 127

shelf clocks 129

shellac

as adhesive 159

polish application 113, 145

polish removal 104, 144

slate 149, 152

blacking 156

sliding tenon joints 110

stone clock cases 149

cleaning 153

composite construction 158

cuprous stains 155

damage from self adhesive labels 155

gilding 162

oil stains 155

poultices (cleaning) 154

rust stains 154

sanding and polishing 161

stain removal 154

wax surface protection 156

styles and fashions 18

sweet chestnut 31

sycamore 31

time consciousness 10

tools

recutting saw 40

sharpening a chisel 37

sharpening a drill bit 38

sharpening a gouge 38

sharpening a saw 40

tulipwood 34

turned balusters 89

turnery 45

turning 59, 137

large turnings 63

veneers 135

adhesives 49

applying 49

Vienna clocks

Alt Deutch style 132

American 132

baroque 132

Biedermeier style 132

the Empire Period 131

Vienna-type clocks 131

German variant 139

Vitruvian scroll 46

wag-on-the-wall clocks 128

wainscott qak 27

walnut

burr 30

european 29

red 29

wood

colours 97

construction 22

deals 22

European hardwoods 25

finishes 97

in the history of furniture 25

lime wood 25, 61

pine 25, 71

salvaged 71

softwoods 22

types 22

use of endangered species 26

veneers 22, 29

woodworm treatment 134

workplace 36

safety 36

yew 31

zinc alloys 171, 182

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