Count wheel issues

(Thanks to Phil for his question that helped to formulate this part)

COUNT WHEEL PROBLEMS AND SOLUTIONS:
Cuckoo clocks have their own special set of situations. Many cuckoo clocks of the count wheel variety use only gravity (as opposed to spring activated return) to bring the levers back down after the centerpost cam or wire trips the strike gear train into the lock and then release routine. Because of this, the play in the bushings that the trip levers ride in must be as friction free as possible with as little play as possible – yet still allowing the lever to be free to move. All of the angles on the working faces of these levers are critical. The shut off lever must grab the pin on the warning wheel (5th wheel) with about the thickness of the pin to spare – usually, depending on the amount of weight used to run the particular clock you are working on. The count wheel must not be loose on its bushing mount, if it moves (wobbles) slightly then there could be shutoff problems. The weights must be appropriate for the mechanism and many of these older clocks have had the weights replaced so long ago that it may not be possible to know if they are the original or not. Have a test rack to set the mechanism up on outside of the case. Watch the levers carefully as they operate. If they pop up slightly when the strike is tripped into the “lock” position the angle is wrong or the working face of the lever where it meets the pin in the 5th wheel (warning wheel) is defective. The pin in the warning wheel may be slightly loose. Watch the trip and shutoff levers while the mechanism operates they should not move around “much”. The “much” is the caveat because it takes a lot of experience to know just how much wiggle in a shut-off lever is too much.

Consider the play in the center post, the warning wheel bushings, the trip lever and the lift levers’ bushings, and the count wheel bushing: 2 thousandths of an inch off on each makes 5X2 or 10 thousandths of an inch – enough to cause problems, and the position of each may come together in the additive mode irratically causing problems in a very chaotic way, or there may be a pattern to the additive errors every 360 degrees or 180 degrees since we are deaing with circular motion. Getting the feel for how a mechanism should act is the key to success. After watching enough of them you will have enough of an idea of how they should look that it will get easier to find the problems.

Now spring drive mantle clocks of the T&S count wheel variety… Most of these (but not all) will have return springs on the shutoff lever. Often these springs are fatiqued or have been replaced with material of incorrect strength. This is a weak point on this type of mechanism. The end of the shutoff lever that fits into the slots on the count wheel can get a groove worn in it over many years of operation. This little square groove in the lever will move back and forth as the shutoff lever’s endshake allows; thus causing the strike to shut off irratically. The same groove can get worn in the trip lever on the center post which will also be irratic depending on endshake modulated position. On old (1800’s) T&S clocks the shutoff levers’ pivots are often worn – this will cause the strike to be irratic. These pivots must be smooth and true (the same is true for cuckoo clocks). They will need to be replaced or reshaped and polished. This can be very difficult because to chuck them up in a lathe and spin them is downright dangerous. If you have wire chucks it is possible to do this but it must be done, as you can imagine, very very carefully and it takes a long time to accomplish this task. Since the angles on these levers are absolutely critical I do not recommend trying to make a new shutoff lever unless you have lots of experience setting them up. If you can devise a way to accrurately measure all of the angles before you disassemble them that might be a viable solution.