There are four general categories of clock mechanisms; quartz, electro-mechanical, electric, and mechanical. Mechanical clocks be they antique or vintage types are the focus of this post and if your clock has stopped perhaps I can help.
It may surprise some to know that mechanical clocks need periodic winding
Perhaps you have a newly acquired mechanical clock that you inherited, was given to you, bought at an antique store, purchased online, and so on. You managed to get it running but now it has stopped.
It may surprise some that mechanical clocks need periodic winding. Eight-day clocks must be wound once per week and 30-hour clocks, once per day. 31-day clocks need only be wound once per month. 400-day clocks, sometimes called anniversary clocks, are wound once per year. There are even many German and some American clocks that run 14-days.
Winding a clock
What does winding a clock actually mean? It means providing enough power to a mechanism that will allow it to run for a given time.
Winding the mainspring implies turning the key until the clock winds no further. Time and strike clocks will have two winding arbours, chiming clocks have 3 winding arbours and if there are no winding holes on the clock face the clock uses weight chains that must be pulled up.
Most spring-driven mantel clocks have winding arbours on the clock face. One key is required for all arbours. Weight-driven clocks may either have a winding crank that came with the clock or the weights are pulled up by hand to the top of the clock to begin the weekly cycle.
In the case of clocks with mainsprings that provide the motive power for the time, strike, and chimes, wind each arbour until resistance is met and you cannot wind any further. One key will fit all the arbours except the regulator arbour which requires a smaller key.
Clocks generally wind clockwise but it is also common to find winding arbours that must be wound counterclockwise.
Overwinding a clock is a myth. A clock that stops when you have wound it fully means that there is dirt, old oil, and grime on the mainspring causing it to seize in place. Even if the mainspring provides plenty of power it needs cleaning, requiring disassembly of the movement, and an inspection for other issues. A clock in good working condition should run its full cycle be it 30-hours, 8 days, 14 days, 31 days, and so on.
Why has my clock stopped?
- Is the clock in beat? Put your clock is on a level surface. Listen to the tick and the tock of your clock. Try to minimize the sounds in the room you are in so that you can listen closely to its rhythm. It is in beat when its ticks and tocks are even….tick…tock…tick…tock…, and is out of beat when they are uneven, either, tick….. tock or tock tick…… Put another way, there must be an equal amount of time between the ticks and the tocks. When a clock is out of beat, it will not run, or it will run for a short time and stop. A clock’s beat must be regular to work properly.
- Is the clock level? There are two ways to put a clock in beat. The first is to tilt the clock sideways, one way or the other, and listen for the beat to even out. When the beat is even, prop the clock to stay tilted that way. If it is a wall clock move the bottom section from side to side till you hear a steady beat. Now it will run in beat but it will obviously not look good.
- Adjusting the crutch Adjust the crutch to one side or the other until the beat is even. The crutch is the rod that extends down from the pallets which rock back and forth on the escape wheel. The pendulum rod passes through either a loop (called a crutch loop) or a forked foot at the end of the crutch as indicated in the photo below. Incidentally, that rod needs to be in the middle of the crutch loop and can’t be tight inside the loop nor too loose. The crutch is attached to the pendulum leader which is then attached to a post with a suspension spring. Other mantel clocks require similar adjustment to the crutch and instructions may be provided on a label or a pamphlet that came with the clock. A clock with a balance wheel or lever-type escapement rather than a pendulum will operate on a non-level surface.
- Have repairs been done recently? Unless you had a friend fix your clock most reputable clock-makers will offer a warranty, typically 6 months to a year. If your clock stops within that time frame, contact the clock-repairer who may offer a few suggestions over the phone prior to taking it back to the shop. If it still does not work have that person take a look at the clock.
- Do you have the correct pendulum? Other than the winding key, it seems to be the item that gets lost the most. Make sure that you buy a pendulum that is correct for your clock. One too light may mean that it does not run at all, too heavy and the centre of gravity is lowered and the clock might run too slowly. Clock suppliers such as Perrin or Timesavers will have the correct pendulum for your clock.
Something is broken? If there is no resistance when turning the winding key, the mainspring has broken or a click has let go. If the mainspring winds but releases in your hand, the most common cause is a broken or worn click spring. This is a repair that requires removing the movement from its case, taking it apart, and replacing the worn or damaged part.
A loud BANG when you turn the key indicates the mainspring has broken or let go. It is not as simple as replacing the mainspring. If it breaks it might have taken out other parts with it such as pinions and gear cogs. This is called collateral damage. An inspection and a full servicing of the movement is the only solution. Occasionally a broken mainspring is the only problem but the broken spring must come out of the barrel. Sometimes the barrel is removable. Even if the barrel is removable, a correct mainspring must be sourced to replace it and installed in the barrel which is a job for an expert.
If the clock has springs within barrels the mainspring might have become unhooked. The mainspring might have become unhooked because an attempt was made the wind the clock backward or the hooked end is split or broken. This means tearing down the clock, opening the spring barrel, and determining what caused it to become unhooked.
In a clock with open mainsprings, the break may be on one mainspring on the movement or the other or both. The clock must be completely disassembled, mainsprings replaced, the movement inspected for other issues, reassembled, and tested.
Why does my weight-driven clock stop? If it is a new acquisition of a grandfather clock the three weights have a specific location. Look underneath the weight shells for marks indicating their location “L”, left side, “C”, center and “R”, right side. If there are no markings, use a scale to determine the one that is the lightest weight and put that on the left side.
When bringing up the weights to the top of the clock be careful that they are not run past their stops. You should have a full view of the weights on a weight-driven clock once wound.
Antique Ogee and other weight-driven shelf clocks often do not come with weights. Eight-day clocks typically have heavier 8 or 9 lb weights while 30-hour clocks have lighter 2 1/2 lb or 3 lb weights. Incorrect weights for these clocks will cause them to stop.
Is the weight cord or the brass cable binding in any way? The cord or cable should be just long enough to accommodate the weights. Cord or cable that is too long will bind while being wound and stop the clock.
Some clocks like weight-driven Vienna Regulators can be adjusted by a transverse regulating screw assembly where the crutch inserts into a slot in the pendulum. Turning a screw in one direction or the other will correct the beat.
Since all clocks require motive power, weights resting on the bottom of the baseboard will stop a clock and a completely unwound spring-driven clock will not run.
Should you have a unique issue not covered above I suggest consulting a professional clock repairer or someone knowledgeable concerning the repair of mechanical clocks. There is a certain element of risk working with mechanical clocks as the power contained in the mainsprings may cause injury if not handled properly.
While this article may not cover every conceivable situation I hope at the very least it gives you a better understanding of your clock issue.