Time Wizard • Repair Procedures

Clock Repair

It would be impossible to go into great detail about all aspects of clock repair on a web site, but I will attempt to provide basic information about different types of clocks and the maintenance they require.

Spring Driven

The mechanism in your clock will come out
good as new once the Time Wizard submerges
the parts in the ultrasonic cleaning tank.
Please don't let this picture frighten you.
Your clock will be in one piece again at some
point in the repair process.

Mechanical spring driven clocks should be lubricated about every two years. This includes all pivot points, escapement contact points, and the mainsprings themselves. When the oil starts to turn dark caused by the accumulation of dust and other debris in the mechanism, then it should be completely disassembled and ultrasonically cleaned at that point. If this dirty oil is allowed to circulate for a prolonged period it will cause damage and wear to the movement including but not limited to worn/oversized pivot holes, scored pivots, premature wear to gear teeth and/or pinions, poor timekeeping, sluggish or non-operational strike/chimes, and broken mainsprings.

A complete cleaning and overhaul almost always consists of the following: complete disassembly of the movement and removal of mainsprings from barrels if so equipped. This process should only be performed using a bench top mainspring winding tool and an appropriate collar to fit the mainspring barrel you are working with. It is not recommended to install or remove mainsprings by hand as this will cause the mainspring to become distorted and press against the sides of the barrel, resulting in poor performance. At this time all the parts are then immersed in an ultrasonic cleaning tank with a good quality commercial grade clock cleaning solution. The solution that I use in my shop is an ammonia based 10 to 1 fluid concentrate. 20 to 30 minutes is usually sufficient. Then it should be rinsed with clear water or commercial clock rinsing solution and dried under forced air heat.

After the drying process is complete, then a thorough inspection process begins. I inspect each of the gears and arbors individually under magnification, looking for wear or damage to gear teeth and pivots. The gears are then chucked up in a lathe and all pivots are polished with fine grade emery cloth to a mirror smooth finish. Then I partially reassemble the movement one gear train at a time, inspecting the pivot holes for looseness and wear. Any excessively loose or worn pivot holes are then marked. Then the movement is disassembled once more and all marked pivot holes undergo the process of rebushing. This involves the use of a bench top reaming tool.

The movement plates are clamped onto the bushing tool with the hole to be rebushed centered under the reamer. It is very important at this stage to insure that the pivot hole is bored out on its original center. If the hole is so badly worn that it looks like an oblong the original center must be relocated prior to reaming. If this very important step is omitted, the new bushing will not be in the proper location and this will affect the clearances between the gears and their mating pinions, either increasing it or decreasing it to the point where the clock will not run. After the holes are centered and reamed, new bronze bushings are pressed into place. The holes in the new bushings are then reamed to size using a tapered cutting broach and followed by a smoothing broach to smooth out any roughness left by the cutting broach and harden the inner surface.

Prior to reassembly, the mainsprings should be lubricated between the coils with a good quality mainspring lubricant. I do not recommend the use of grease on clock mainsprings as it tends to cause the coils to stick together. The mainspring lubricant I use is made by Keystone and comes in different viscosities. If the mainsprings were removed from barrels, now is the time to reinsert them again using the bench top mainspring winding tool. All pivot points should be lubricated at this time and all final adjustments made prior to bench testing. Most clock movements should be bench tested for a minimum of 24 hours prior to reinstallation into the clock. Timekeeping adjustmenets are usually the responsibility of the clock owner. However, while the clock is in my care, I do make adjustments if they are needed. The clock is then returned to the owner with a 2 year warranty and if the recommended bi-annual service is performed, my 2 year warranty is renewed each time.

Weight Driven

Most of the details in the preceding section will apply to weight driven clocks as well with a few minor detail differences in the handling of the chain or cable system. For clocks with chains, the chains should be removed prior to cleaning. The chains do not necessarily need to be cleaned with the movement unless they are excessively oily or darkened and tarnished. The ultrasonic cleaning process will brighten tarnished chains somewhat.

If the clock is cable driven, the cables should not be cleaned with the movement. Many clock weight cables are made of braided brass and quite a few of these have a nylon core. It's not a good idea to soak these nylon reinforced cables as the core will never dry and will ultimately rot. If the cable is frayed or broken or improper length, it should be replaced upon reassembly. Otherwise, in most cases, cable that is in good condition can be reused. I do not recommend the use of gut as it becomes brittle with age. Most of the time I replace existing gut cable with a braided nylon cable.

400 Day or Anniversary

400 day clocks or Anniversary clocks as they are commonly called require much less frequent maintenance than most other types of mechanical clocks. At best, they should be cleaned about every 10 to 15 years to renew the lubrication in the mainspring. The gears and pinions in these clocks should never be oiled nor should the motion works under the dial. Only the pivot points and the anchor impulse surfaces require lubrication and this should not ever need to be renewed as these clocks are under glass and really don't accumulate dust in the mechanism like other mechanical clocks - especially clocks in wood cases - do.

Cuckoo Clocks

Cuckoo clocks are in a class by themselves because often they have mechanical complications other than just the clock itself. Some have music boxes, some have animated moving figures or other parts. Repair and disassembly of these clocks should not be attempted without some experience or at least some serious study. The care and maintenance of these clocks is sometimes needed more often than what you might expect because of the soft wood the cases are made of and the number of openings where dust and debris can enter.

The mechanisms of these clocks, especially the ones made after World War II, are very thin and cheaply made and will not tolerate much wear before they stop running. Depending on the manufacturer and the type of clock, sometimes it is more economical to replace the movement with a new one. If the mechanism is to be cleaned and overhauled, the procedure is very much the same as with any weight driven clock powered by chains.

Electric Clocks

There are two basic types of electric clocks. Those with a motor, and those with a rotor. A rotor generally refers to a sealed encapsulated electrically powered gear train with an output shaft which drives the hands and/or chime mechanism. A motor is an electrically driven disk with a shaft attached and some sort of drive gear on the end to turn the mechanism which drives the hands.

There are several variations. For example, there are many electric clocks where either the chime or the time mechanism is powered by a mainspring which is kept wound by the electric motor or rotor. The main purpose of an electric clock with a spring powered time mechanism is so that the clock will continue to run for a time if the electric power is interrupted. Once power is restored, then the mainspring is rewound again. On electric clocks with spring powered chime and/or strike mechanisms, the only real advantage appears to me to be that a standard spring driven mechanism can be adapted with some modification to accomodate an electric motor driven clock that keeps itself wound.

On clocks with rotors, if the rotor is inoperative or noisy, it may be replaced if a suitable unit is available and these are becoming harder and harder to find. If a replacement cannot be obtained, the sealed rotor must be chucked up in a lathe and cut open to affect repairs, then reassembled and resealed. After all necessary cleaning and repairs have been completed, these clocks should be lubricated and serviced just like any of the mechanical clocks described above.