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Missing tooth - repair?

p2n

By p2n
in Watch Repairs Help & Advice

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p2n WRT Addict

p2n

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Thought I was in for a bit of success - broken mainspring. Ordered, arrived and fitted.

Testing the gear train before refitting the balance and it kept skipping.

A closer look and there is a tooth missing on the mainspring barrel

If I solder the gap, then file out a new tooth will that be string enough? I'm assuming that if left it will only get worse with the impulse shocks to the next tooth around?

 

P3210006.thumb.JPG.b4f8cb63d05b428e11a62f141680c3c9.JPG

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rogart63 Distinguished Member

rogart63

Posted
Posted (edited)
13 minutes ago, p2n said:

Thought I was in for a bit of success - broken mainspring. Ordered, arrived and fitted.

Testing the gear train before refitting the balance and it kept skipping.

A closer look and there is a tooth missing on the mainspring barrel

If I solder the gap, then file out a new tooth will that be string enough? I'm assuming that if left it will only get worse with the impulse shocks to the next tooth around?

 

P3210006.thumb.JPG.b4f8cb63d05b428e11a62f141680c3c9.JPG

On the mainspring barrel i have seen it. Look at this. https://anderstestarblog.wordpress.com/tag/tandinfallning/

Edited by rogart63
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p2n WRT Addict

p2n

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Wow - thats fine work. I don't think I could do that but I could adapt the idea. If I remove the broken tooth, file and solder in a piece of brass, I could file that into teeth. Assuming I can find a file small enough...

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oldhippy Distinguished Member

oldhippy

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Silver solder would be stronger, but lead solder will do a fine job. First, find a piece of brass suitable for the job. You need to file a slot into the barrel and solder it in. You can use a spirit lamp and some flux. You will need to clean the piece of brass to use, use a emery stick to clean it off. With various needle files, file the brass into the shape of the tooth making sure you have the correct height, thickness and shape. You will need burr files or some people call them rotary files to remove the inside waste so the spring can sit proper. Test it before you put the movement back together, you might have to make slight adjustments. If you have never done this type of work before you might like to practice on a clock wheel, which is bigger to get the idea on what to do, if you make a mistake it does not matter.

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