Antique Clocks/Clock hands don't move
I recently bought an old cuckoo clock. The movement stamping is: Hubert Herr Triberg Germany unadjusted and no jewels. It seems to be ticking OK, but neither the minute nor hour hand move on their own. If I move the hands manually the cuckoo section appears to work. There is little back-resistance when moving hands manually. If a gear is stripped, will I have to replace the entire movement? Can I repair or replace one or two gears?
I doubt your problem is caused by a defective gear. The torque on these gears which drive the minute hand is extremely low. Possibly, the gear may have shifted position and is, therefore, not driven. A more likely cause of your problem is a defective minute hand drive clutch. This clutch is what enables you to turn the hands and it should be fairly snug. Usually the problem is caused by the collar which maintains tension on the clutch spring oxidizes, weakens, and slips on the minute hand shaft. This greatly reduces or completely eliminates the pressure on the spring which causes the minute to rotate as the clock runs.
To remove the movement from the clock, you may have to remove the cuckoo whistles. On some of the larger clocks you do not have to do this. In any case, remove the movement and first check gear alignment. Keep track of which rods actuate the whistle bellows and carefully disconnect them. Be careful to not place too much stress on the bellows as they tear easily. The repair will probably require disassembly of the movement or at least removing the front plate. The little collars take the form of thick washers and are pressed on to the various staffs of the movement. It will be apparent where the problem is. I have not had much success buying parts for clocks and generally make my own. Possibly a local jeweler or clock repair facility could help you there. That hole has to be very precisely drilled using the appropriate number drill chucked in a drill press or lathe as it has to stay in position once pressed on.
It may be necessary to pull the gear on the front of the minute hand shaft. A puller for doing this would be available from Merritts (www.merritts.com).
Sometimes there is room on the staff for a set screw type collar or there may be one there already that could be causing the problem. This would do away with the need for the precise drilling of the hole. A suitable collar could be made in a metal working lathe, however, you would have to get a number drill of the exact size to drill the hole. You could make the collar out of aluminum if you do not have brass available.
The cuckoo movement has some precisely timed gears like the timing gears and chain used on gasoline engines. They will not cuckoo correctly if you do not get it back together exactly as you took it apart.
New cuckoo movements are available from Merritts. I do not know the price, you would have to contact them for this information. I met a gentleman in Pecatonica, Illinois, who operates a clock shop that makes gears and other parts for clocks. His name and number are Tick Toc Clock Shop, Inc., Matt Clark, (815) 262-2281 and his email is: email@example.com
I hope you have success in fixing your clock.