Repair

Firstly, I should explain the meaning of the terms service, repair, restoration, and conservation, in relation to clocks:

Service implies that all aspects of the clock are working and is analogous to a routine car service. It usually involves stripping, cleaning and lubricating the clock.

Repair means getting the clock working and possibly improving its appearance. It usually involves fitting, making or repairing parts.

Restoration is similar to repair but implies using the methods, materials and parts available at the time the clock was made.

Conservation implies preventing deterioration without adding to, or altering, the clock in any way. Taken to extreme, conservation implies that the clock is no longer allowed to tick!

In reality, the ‘repair’ is usually a combination of all four aspects. However, whatever work is done, it should be done sympathetically, with due regard to age, condition, type, and cost of the clock. For example, a 200-year-old clock must not be made to look as thought it was made yesterday. Of course, the clock repairer can only recommend a course of action. It does not follow that the customer will (or can) take his advice – cost being an important factor.

For brevity, throughout this site, the word ‘repair’ is used to encompass all the above. Also, the terms ‘clock repairer’ and ‘clock maker’ will be used in their strict literal sense to distinguish between someone who repairs, and someone who actually makes clocks.

Decision to Repair: To repair a clock properly takes time and skill, and that costs money. The customer needs to consider whether to repair, scrap, replace, sell, use as decoration, or put the clock in the loft and forget it! If the clock has no sentimental value then the decision should simply be a matter of raw economics. Ironically, sentimental value, or otherwise, often determines the fate of a clock.

The cost of the repair does not necessarily relate to the value of the clock. For example, the work involved in repairing the movement (mechanism) of a mass produced, 1940s, chiming clock, which may have cost just a few pounds from a car boot sale, is similar to that of repairing the movement of an antique chiming clock worth several thousand pounds. In fact, mass produced clocks are often more problematic to repair because the parts are less robust, the wear which has taken place is often greater, and the movements generally more difficult to assemble.

Another consideration is: Does the clock have investment potential? For example, the English Dial clock shown on my Home Page cost £2.50 thirty years ago and is probably worth £500 + today, so it was undoubtedly worth repairing. However, it is not easy to predict what will, and what will not, be a good investment.

Unlike many modern appliances, most clocks can be repaired even if they are in poor condition. Many parts are still available off-the-shelf, but parts which are not can generally be made by the skilled repairer or specialist supplier. Again, it is a matter of cost.

Finding a good clock repairer: As I said earlier, horology has more than its share of bodgers. In choosing a repairer, one should look for someone who has: a British Horological Institute qualification, Higher National Diploma in Horology, or certificate from West Dean College. In addition, one would expect to see evidence of the quality of their work. Personal recommendation is useful, but the recommender needs to be knowledgeable. The clock repairer should advise the customer on technical matters, history, current and potential value of the clock, as well as provide an estimate of the cost and time to repair. Lastly, try to use a local repairer – clocks do not like being sent thought the post!

The following section deals briefly with servicing, repair, restoration and conservation in more detail and is based on current best practice:

Preliminary inspection: The mechanism/case should be inspected in order for the clock repairer to recommend a course of action. It is important that both parties are in clear agreement regarding the work to be undertaken.

Very dirty clock complete with dead spider!

Service: A routine service consists of taking the clock movement apart, cleaning the parts individually, assembling, lubricating, testing the mechanism, and finally regulating the clock. Minor repairs, such as bushing some worn pivot holes, are normally included in the price of the service. The important point is that, to do this work properly the clock has to be completely taken apart. The reasons for this are that there is no other way of inspecting/cleaning/repairing parts such as pivots, springs and pivot holes.

Parts of Westminster Chime clock

Mainsprings removed from barrels

The cleaning method and chemicals used will depend on the type of clock and finish used by the manufacturer. For example, if the clock plates have been lacquered, one would avoid the use of harsh chemicals and ultrasonic cleaning methods. It goes without saying that reassembly must be done very carefully!!! The types of lubricant and method of lubrication is vitally important. One of the worst offenders used by the general public is a popular brand of water repellent spray lubricant. This causes etching/discolouration of the brass parts and evaporates to form a 'dry' film eventually causing the clock to stop. The clock repairer should use proper clock lubricants such as those made by Moebius, Switzerland.

The question is: What is the service interval? I am not aware of any quantitative research, but the general consensus amongst clock repairers is between five and ten years. For a long case clock, which has been ticking day and night for ten years, this represents over 300 million ticks!

Common problems

This section is written with the clock owner in mind, and describes briefly common problems, how they arise, how they can be avoided, and how they are best corrected. The photographs on this page are of some of my own repairs and some of the problems and bodges encountered. It is not my intention to provide a DIY guide to clock repair. However, for those interested, my 'Information' page suggests some useful publications and study courses.

Lubrication: Over time the oil and grease dries out or is drawn away from the sliding parts and the clock stops. However, before this occurs airborne dust is trapped in the oil and forms an abrasive paste which causes wear. In other words, do not wait until the clock stops before servicing - damage may already have been done. A common bodge is simply to re-oil the clock without stripping and cleaning. In which case, the abrasion remains and the wear continues.

Worn bearings and pivots: The correct method of repair is to bush the clock plate, remove any scoring from the pivot, burnish the pivot and broach the hole to give the correct fit. If done properly the repair should be hardly noticeable.

Winding arbor bearing bush with oil sink

Punched region around a hole!

A common bodge is to punch the area around the hole to make the hole smaller - this is a HUGE NO NO!

If the pivot is so badly worn that removing the wear would make the pivot too weak then the pivot has to be cut off, the arbor (shaft) drilled, and a new pivot fitted. This is one consequence of not servicing a clock, or re-oiling without stripping and cleaning.

Badly worn pivot

Damaged pivot removed and new pivot fitted

Mainsprings: The three common problems with main springs is hooking, setting and lubrication. Hooking relates to the fastening at the inner and outer end of the spring to winding arbor and spring barrel respectively.

Broken and repaired hooking

The problem is that the hooking may be torn or completely broken and this usually occurs at the outer end of the spring. If broken, the clock key can be turned easily without any resistance. The danger is that if the hooking breaks, the ensuing shock may damage wheel or pinion teeth. This is another reason for stripping the clock and correcting the problem before it occurs.

Spring on the right has 'set'

Setting relates to loss of 'springiness' with time. In other words, if the spring is removed from the clock, it is smaller in diameter than it should be. This can cause the clock to stop prematurely (there are also many other problems which cause clocks to stop). Most clocks are designed to run for 8 days (wound every week). Setting of the mainspring/s can only be diagnosed by removing the springs. Refitting a mainspring requires a special tool and care to prevent damage to the clock and damage to one's fingers!

Thick degraded oil/grease

In many clocks, main springs are enclosed in barrels. The temptation for the bodger is to not to remove the spring from the barrel (see above) but merely to pour in more oil. The problem is that, over the years, the oil thickens and becomes a dark gummy paste which prevents the coils of the spring sliding across one another freely. The clock stops. To diagnose and correct the problem, the spring must be removed from the barrel, cleaned, checked for any problems, lubricate with reputable clock grease, and reassemble.

Wheels and pinions: Wheels and pinions are clock-making terms for gears. The wheels are the larger and are usually made of brass and the pinions are steel. There are two main problems associated with wheels and pinions - wear and broken teeth. Ironically, wear is often caused by lubrication. Clock wheels and pinions must never be oiled! The problem is that dust becomes trapped in the oil to form an abrasive paste, the particles of dust become embedded in the softer brass and cause the steel pinion to wear. There are two possible solutions. In some clocks it is possible to move the pinion along the arbor (shaft) so that an undamaged region of the pinion engages with the wheel. If this is not possible then a new pinion and possibly new arbor has to be made which is relatively expensive.

Damaged ratchet teeth

Damaged barrel teeth

Damaged teeth are caused by fatigue or by shock if a mainspring breaks. A skilled repairer can remove a broken tooth and 'dovetail in' a new tooth so that the repair can hardly be seen.

Damaged teeth removed using dovetail cutout

Teeth blanks

Teeth blank soft soldered in place

Teeth filed to shape

If several teeth are missing the repairer may decide to make a new wheel. However, for restoration purposes replacing individual teeth is preferred. A common bodge is to remove the broken tooth, drill a hole in the edge of the wheel and knock in a peg. This looks awful, is weak, and prone to rapid wear.

Lantern pinion with bent trundles

Lantern pinion with trundles replaced

There is another type of pinion called a lantern pinion which is commonly found in German and American mass produced clocks. The structure is open and the 'teeth' comprise of small rods called trundles. Wear is treated as above. If a trundle is bent or missing it should be replaced.

Trundles should not be soft soldered in place!

Trundles are held in place by peening and not, as often seen, by soft soldering. Indeed, the use of soft solder in clock repair is very limited.

More information

There are many, many, other clock problems that can arise but which are outside the scope of this site. My 'Information' page includes a suggested bibliography for those who would like to learn more about clocks. However, the best way to learn is to enroll on a recognized horology course and my 'Information' page also gives brief details of courses. In my case, I studied Horology for three years full time at the University of Central England.