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Cuckoo Music Box Click

MuensterMann

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Mar 23, 2008
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During the music/dancing sequence on my cuckoo clock, I would hear a steady clicking noise. I first removed the music box and found that the clicking is coming from the box and has the frequency of each full revolution of the gear that drives the worm. I don't see anything obvious that could be causing this. Has anyone had this problem and if so, what was it and how to your quiet the click? Thanks!
 

disciple_dan

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Hello, I just finished my 3rd or 4th music box so I'm not an authority but all the ones I've done had the white plastic gear cracked. I purchased some from blackforest imports and replaced the gear and arbor.
 

Vernon

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Yes, this plastic gear is on the governor assembly. Most likely the issue.
 

MuensterMann

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Mar 23, 2008
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There is a white plastic gear that drives the worm. This is what you are referring to? And, you say that it cracks - and it causes a click sound on each revolution? And, you say that BFI carries this arbor/gear component?

The cuckoo clock is probably about 15-20 years old I imagine.
 

disciple_dan

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Yes, Black forest Imports carries two different sizes. I got the larger size, (only longer I think) but they were still too short. What I did was find a long bushing (KWM L94) and put the bushing on the pinion end and I had to tweak the gear end housing just a little bit. I first had to move the plastic gear down the arbor just a little. It's just a friction fit on the arbor.
I've done 3 of them that way and had great results.
I'm going t make some special bushing that a 3mm long and has the exact size hole.
It has really worked well for me.
Or you can by a new housing for around 28.00 I got 5 gears for 6.00.
 

disciple_dan

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This is the bushing I put in to make the fly gear work.
20190504_214526.jpg
Old gear showing crack.
20190504_214557.jpg
I always take them completely apart and clean the pivots and pinions also. They do get quite dirty.
I hope that helps you out, Good luck, Danny
 

MuensterMann

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Mar 23, 2008
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Thank you for the information! You get 5 gears only for $6? I see gears on arbors for $47 (for 5). Assemblies seems to be about $45 at the sites I have been looking at. Perhaps you bought long ago?
 

disciple_dan

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If you have a clock repair business and an account with Blackforest it's half that price.
 

Peter John

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You know if you pinch the split closed while off the shaft and the take a small 25 watt soldering iron you can remelt the crack closed. You also need to take .001-.002 off the diameter of the shaft. Putting the gear back on with red loctite will fix it firmly in place. I have done lots of them like that. Peter
 

MuensterMann

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I tried the melding with a soldering iron technique and it seems to have worked. Well, so far. It was hard to get the arbor back in the holes, since you have to bend one end of the mechanism to get the arbor out - and then bend it back to hold the arbor. It is that bending it back that is tricky.

It may hold, but I want to be familiar with buying a new one or perhaps a new governor. It seems a new arbor only would be better than buying the whole governor mechanism, cause you have to modify it as well. Do they sell just the plastic gear? That is all one needs - and not the whole arbor. The reference to 18 or 22 or 28, is that the amount of tines on the comb?
 

disciple_dan

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If you are going to be working on these often I think it's a good idea to learn how to repair them. If you are just fixing a clock for yourself or a friend you might be better to buy the unit.
Depending on how you value your time I guess. The first one I did took over an hour but I've cut that time in half or less.
Yes, that is the tooth count.
 

MuensterMann

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Mar 23, 2008
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So, it is the cracked plastic gear that really does cause the clicking! Just need a bunch of those gears if they are common to crack.
 

disciple_dan

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I have tried to just change the gears out but the new ones seem to have a bigger arbor. If the new one has a smaller arbor you may be able to ream it out and fit on the old arbor.
 

Willie X

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Feb 9, 2008
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Most MB repair parts were unavailable for quite a few years. There is now only a trickle of new parts available and they are often not direct replacements. The "plastic gears" were used heavily from around 1970 to about 2005. On newer clocks this part has been replaced with a metal gear. The older plastic gears have only recently become available again.

The bad thing about working on MBs is that you have no way to know if the parts you order can be used on the MB you are working on. Try this and try that until (hopefully) you come up with something that will work. All the leftovers go in the MB parts drawer, sometimes you will get lucky and have the right part on hand!
Willie X
 

kinsler33

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Thank you for all this. I had no idea that the plastic gears were available in any form at all. Replacing the entire governor is difficult because they never fit, and replacing the whole music box is even worse for the same reason. I believe that those plastic gears are made of a questionable grade of nylon that's self-lubricating, very accurate in molding, and which shrinks in size after several years. The gear shrinks but the arbor does not, and the tension cracks the gear from the hole to the root of the teeth.
 
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exit408

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You know if you pinch the split closed while off the shaft and the take a small 25 watt soldering iron you can remelt the crack closed. You also need to take .001-.002 off the diameter of the shaft. Putting the gear back on with red loctite will fix it firmly in place. I have done lots of them like that. Peter
What technique do you use with the soldering iron to accomplish melting this plastic back together? I understand pinching it closed.
 

Peter John

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After it is pinched shut I use the hot tip of the iron to melt the crack edges. This is not a strong repair. It will crack again if you try to shove it on the arbor. That’s why I reduce the arbor diameter by .001-.002”. Then use red loctite. Peter
 

shutterbug

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I've never heard of red Loctite being used effectively on plastic. I thought it was only for metal on metal. How sure are you of it for this application? Just curious.
 

Peter John

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It’s been working for me for years. Probably enough roughness inside the gear and arbor that once it’s set up it’s enough to do the job.
 

kinsler33

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I believe that it's a good deal easier to enlarge the hole in the gear than it is to turn down the shaft. That's how I've done it.

Mark Kinsler
 

exit408

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Peter, thanks for your prompt response. Your method worked great. I am confident in the repair, there is not a lot of pressure on this gear I believe the initial crack was due to it being pressed too tightly on the arbor. I attempted to enlarge the hole with a cutting broach but the crack opened back up so I reduced the arbor. I repaired one from a box to practice with first, Both are working fine. Thanks again! Donald
 

kinsler33

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If possible, just clean out the crack as best you can by running a thin wire down it. Then enlarge the center hole in the gear such that it's a slip fit onto the arbor. Finally, use whatever adhesive you believe in to glue the gear to the arbor. To further reinforce the repair you can drill a _tiny_ hole or two on either side of the crack and sew it up with fine brass or steel wire.