Worm gear on 3-train cuckoo mechanism

lbrott

Newbie
Jan 2, 2015
23
6
3
Country
I bought a cuckoo clock dumped in a cardboard box with other old clocks from an antique store. I cannot guarantee that I have all the parts.

I cleaned everything and am slowly putting it back together. I have gotten the time portion to talk with the "cuckoo" portion, and now I'm trying to get the cuckoo portion to talk with the music portion. I am almost there, except for the gears that turn the large music fan. The round traditional gear would rather push the worm gear downwards instead of turning it.

I looked closely at the base of the worm gear, which is different than most photos I've found of this mechanism (for example, look at the photo in this post "https://mb.nawcc.org/threads/musica...tween-plates-strike-and-music-problem.185297/" ).

Should I have a ball bearing trapped at the bottom of the worm gear? The worm gear turns freely when I turn it with my fingers. It just doesn't want to turn when the traditional round gear tries to turn it.

Any suggestions are greatly appreciated!

Mechanism.jpg Close up 01.jpg Close up 02.jpg 2 Door cuckoo clock 01.jpg
 

Willie X

Registered User
Feb 9, 2008
17,145
2,999
113
Polish the worm gear. A muslin buff, charged with Tripoli, held in line with the grooves, will do it.

The lower worm gear pivot tip should be spherical, or pointed, and the little thrust disc should be rotated to a place with no wear (flat).

A small amount of thin clock oil can be wiped on the tips of the driving wheel, to help get things started.

Once it runs a for a while it will probably be fine, assuming the train is good and the weight is correct. Willie X
 

lbrott

Newbie
Jan 2, 2015
23
6
3
Country
Thank you, Willie X! I hadn't thought about buffing the worm gear. I thought a thorough cleaning would be good enough. I will give it a try.
 

lbrott

Newbie
Jan 2, 2015
23
6
3
Country
I am pleased to say that everything appears to be working well, and the mechanism is now going through its weeklong test on the stand.

To conclude, I'd like to share some observations for any future person with this mechanism:
  • The mechanism uses 2 "cuckoo wheel coil spring right strike side" springs from Timesavers (part # 10568). It uses 1 left strike side (Timesavers part # 10567).
  • The "cuckoo" and "time" chain wheels are very close to each other and would rub against each other. This was the cause of my mechanism mysteriously stopping.
  • The mechanism's beat rate is approximately 7928 bph.
  • The chain is 62 links per foot (see the attached photo).

Chains.jpg
 

lbrott

Newbie
Jan 2, 2015
23
6
3
Country
The mechanism has performed flawlessly this past week, so I decided to attach the music box. Everything still performs well, though the music plays awfully fast. I'm currently using 750-gram weights, and 500-grams won't trigger the music sequence. The huge fan doesn't seem to slow the music down much. I may experiment by adding a fan to the music box mechanism itself.

I have added additional photos of the working mechanism to help future repair people, with an emphasis on the levers. Notice that there is about a 0.5mm gap between the long lever from the cuckoo side over to the music box levers (see photo "Levers 05").

Levers 01.jpg Levers 02.jpg Levers 04.jpg Levers 05.jpg Mechanism 01.jpg Mechanism 02.jpg Mechanism 03.jpg
 

Willie X

Registered User
Feb 9, 2008
17,145
2,999
113
The speed on the music depends on that big fan. The fan is usually pretty loose but it can't be to loose. When the train stops the fan should continue rotation for maybe 2 turns.

Looks like you went from one extreme to the other there. :)

Willie X
 

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