Chains on cuckoo clock spontaneously keep jumping and falling from sprocket wheels

silverstreak

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Apr 11, 2021
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I bought used cuckoo clock few months ago. Over time chains spontaneously keep jumping and falling from sprocket wheels. It happened six times this week. So i finally decided to disassemble the clock and found out that chains are to big and don't fit properly in sprockets. Am i interpreting something wrong here, or do i really need new chains? IF so where can i buy them in EU?

20210411_212449.jpg
 

Dick Feldman

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Not near enough information.
If the chains are derailing from the sprockets, I would guess you have the wrong chains.
Too bad you had to take it apart to find all of that out.
A clear photo of the back plate on the clock will help.
Best Regards,
Dick
 

POWERSTROKE

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Jan 11, 2011
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Worn chains or incorrect chains. Brings up great question I have. Is there a way to tell Hubert Herr vs regula chains, both 1 and 8 day?
 

Willie X

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Feb 9, 2008
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Those chains appear to be way to big. Lots of clocks are just thrown together to make a sale. A chain from here, a weight from there, throw in a pendulum, you know. Willie X
 

silverstreak

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Apr 11, 2021
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As said before i still believe that chains are too big. My clocks wheels sprocket has 7 cogs. It is one day clock so wheel moves 14 links of the chain per hour. Effective sprocket wheels diameter is 22mm. So I calculated the ideal chain for this clock is roughly 62 Links Per Foot. I'm still wondering what chains do i need, and where to buy them in EU?
Here are some more images, but i doubt that they will be helpful.

20210412_162335.jpg 20210412_162412.jpg
 

shutterbug

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I think in your country you would use Cousins. There's another popular one too, but the name escapes me now. Look under the chain section when you click on the link.
 

shutterbug

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Oh. You'll be paying for shipping and perhaps customs as well. You'll have to find which country charges least for shipping costs. You might find something on Ebay. Avoid items from India. Their quality is often quite poor.
 

shutterbug

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When you get the new chains, take the weight end off your old chain and hook the end of the new chain to the bottom link in the old. Then just pull the new chain onto the wheel just like you were winding the clock. That will save you a lot of frustration ;)
 

silverstreak

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Thanks for advice shutterbug, but my clock is already disassembled. Cheapest chains i could find are from Cuckooclocks. Two of them cost 16.45€, and a friend of mine can bring them to me free of charge in about two weeks. But they only have Regula 1 day chains and my mehanism looks like Hubert Herr. Which brings up another question. Will loss of those two chain links per foot make any difference? Or do i need Hubert Herr chains?

Tomorrow after work, im also going to check a few local watch repair/shops, but without too big expectations.
 
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silverstreak

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Yes,you need the Herr chains. Trying to use chains of the wrong pitch will cause binding and jumping,same problem you've got now.
Just calculated that chains i was using until now have 47 links per feet. That is a difference of 12-14 lpf. Than again is my clock Hubert Herr? Mechanism doesn't have any marking whatsoever.
 

Willie X

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I can't positively ID that movement but the harp shape in the back plate leans heavily to Regula? Is it stamped H Herr? Willie X
 

silverstreak

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After spending little more time reading about Hubert Herr and Regula difference, im convinced my clock is Hubert Herr. As POWERSTROKE noticed lever on the strike side is silver, and bird movement looks exactly like Hubert Herr. Didn't have any luck with local watch repair/shops. Cheapest Hubert Herr 1 day chains i could find with shipping cost me more than 70€. Since i paid my clock about 30€, those chains are out of the question. Also read here that you can use Regula chain on Hubert Herr movement, which sounds kind of logical (difference of only 2 links per foot). So im gonna try my luck with that.

Will post results in few weeks when i get a chance to test the chains.
 
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POWERSTROKE

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Jan 11, 2011
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The regula chains will jump. If the chains you have now are Hubert Herr you can manually with needle nose pliers carefully close the open links back into shape 1 by one. I’ve done it and it will work.
If not check your pm.
 

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