Conservation

Conservation has become a 'buzz word' and is perhaps over used, but in the field of Horology as in other disciplines that deal with old artefacts, it is important.

It is often said that as the owners of clocks, they don't really belong to us, we are keeping them for future generations. In which case we ought to ensure that the clock those future generations receive into their keeping is the same one that we have now.

This is particularly difficult in the case of clocks. Unlike say a piece of art or furniture, in order to be appreciated they need to be working. Unfortunately a working mechanism wears. If we don't maintain it, it will eventually wear out. The rectification of that wear changes the clock, but if left worn and not working it may be discarded. Here lies our principal dilemma!

It may well be helpful to define some terms now to help us understand the complex issues involved. These definitions are generally accepted in the field of Horology and have been taken from 'The Conservation of Clocks and Watches' published by the BHI in 1995.

Repair

The mending, that is, the putting into functional order of a clock. This can include work on a part or the whole of the mechanism. It may involve fully dismantling, cleaning, re-assembling, lubricating and adjusting a clock. The outcome of the work will be that the item is fit for further use without risk of damage or rapid deterioration.

Restoration

The reinstatement of a clock to its conjectured former state and function. The item would be restored to the condition that it is believed the maker intended. It is likely that research will be necessary to determine the design and finish of damaged or missing components. The degree of intervention will depend upon the type of item and its un-restored condition:

Inappropriate components can be removed.
Missing components can be replaced.
New parts may be purchased or made, or similar parts adapted to suit.
Previous changes from its original state can be reversed.
Surface finish can be returned to the style of original.
It is not acceptable to alter the 'structure' of the clock to accommodate new components.

Conservation

The stabilisation of a clock so that it is preserved in its existing state. The conservation of a working clock will necessitate periodic cleaning and lubrication; any further work should be, as far as possible, reversible and be limited to the necessary minimum intervention:

The clock will be cleaned to remove surface dirt, congealed oil, etc.
The patina present on plates, etc, should remain.
Restoration of component/s is only considered appropriate to safeguard against future damage which would result from breakage of a part or accelerated wear because of worn or unsuitable components.
Design faults that seriously affect the operation of the piece may require modification to ensure reliable working or to prevent future damage or accelerated wear.
Corrosion should be treated to prevent further deterioration, but there is no attempt to refinish areas to remove signs of corrosion.
As far as possible, all aspects of its 'life' up to the present are considered to be part of the history of the clock or watch and should be retained.

More recently the BHI issued a document to give guidance to students and established repairers. As well as repeating the above definitions, it sets out some new ones recognised by PACR and ECCO, organisations that principally recognise conservator-restorers working within museums. I am not registered by either of these bodies and do not consider it appropriate in the area of 'commercial clock repair'. Those who are PACR Conservator Restorers are obliged to apply their principles to all their work, ruling out approaches that vary depending on the age, quality and value of a clock. However for Longcase, Bracket, French Clocks and some others, they have a definition which matches my own approach fairly well - but not rigorously. It is called Conservative Repair: I show my main exceptions in italicised parenthesis.

Conservative Repair

The mending, that is, putting into functional order of a clock or watch with the minimum of necessary intervention and ensuring, where possible, all work is reversible.

The purpose of cleaning is to only remove substances detrimental to the preservation of the object – the soaking of movement parts in ammonia solutions is not acceptable. It is permissible to wash visible movement parts in such solutions to remove excessive tarnishing.
Action should be taken to arrest and/or remove corrosion.
The re-polishing/graining of surfaces for aesthetic purposes is generally not acceptable. (Carriage Clock plates are lightly polished, as they are visible in normal use).
Care must be taken to ensure that evidence of original finishes, such as gilding, is not destroyed during the repair process.
The surfaces of pivots, striking levers, pallet faces, etc. may be re-finished but it is not necessary to remove all signs of wear; this is not usually required to ensure the continued reliable functioning of the item.
Bushes should be fitted with the minimum loss of structural material and driven flush to the inside of the plate to avoid filing and refinishing. New oilsinks should not be formed if it requires metal to be removed from the plate.
Whenever possible replacement parts should be wholly in accordance with the original detail; e.g. rubbed in jewels should be replaced with similar jewels.
Any replacement parts, essential for the safe operation of the item, must be made so that changes to the 'structure' of the piece are not required.
An existing mainspring may be retained even though it results in a reduced duration. (Rarely).
New parts would be fitted as given in 'Repair' (f and g) but only if essential to the functioning of the clock or watch or to prevent damage or increased wear in the future. The removed parts would be retained and, where possible, new parts made clearly identifiable by marking.
Appropriate records, both written and photographic, should indicate which parts were replaced and when. (Usually kept as my working records but available in printed form with photographs at additional cost).
Laser welding techniques should be considered to overcome worn components, e.g. clock pinions, but there must be a careful consideration of the possible result. For example a “refurbished” pinion could increase wear on the adjacent driving wheel. (Rarely).
Dials, should only be sympathetically restored after very significant deterioration and when they are no longer serviceable. (Usually I contract such work out to specialists).
Replace 'consumable' components, e.g. batteries.