Hamilton 940 double roller need jewel pin

rstl99

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Oct 31, 2015
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Hi all.

My Hamilton 940 (s/n indicates later double-roller) needs the roller jewel pin (broken off).

Otto Frei indicates it needs either 0.48 or 0.50mm (length 1.10mm).

Could you please provide me the correct diameter and length if you know it, so I can order and complete my restoration project?

Thanks much.
Robert
 

rstl99

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Oct 31, 2015
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If it's broken off you can dissolve the shellac in warm alcohol and measure the remaining bit with a micrometer.
Thanks, good suggestion. I assume the length suggested by Ofrei is ok (1.10 or 1.20 mm)?
 

Chris Radek

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Apr 13, 2014
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I have a 940 balance here that may or may not have the original jewel in it. It measures 0.47 and appears to be about 1.2 long. I think I would get the longer of the suggested ones since there is lots of room above for it to stick out if it's a little long.
 

rstl99

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Oct 31, 2015
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I have a 940 balance here that may or may not have the original jewel in it. It measures 0.47 and appears to be about 1.2 long. I think I would get the longer of the suggested ones since there is lots of room above for it to stick out if it's a little long.
Thanks Chris.
I just got back the balance from my 80-year old ex-watch repairman neighbour, who said he could put on the balance staff for me. He told me the jewel is broken, but now that I look at it with my microscope, I agree the piece at the top of the dog-bone shaped component looks broken, but below that is what looks like a good jewel (green arrow). I've never seen what they look like, this is my first Hamilton. So I'm not sure at this point which side the jewel is supposed to stick out.
Anyway, does it look ok to you? If so, all it might need is the balance staff replaced, and if my neighbour was wrong about this, maybe I'll have a go at it myself!
Regards,
Robert

IMG_7052.JPG
 

Chris Radek

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Yes the staff is clearly broken. The roller jewel is fine, it needs to have the old shellac cleaned off and then it needs to be installed properly with new shellac. It just became loose and got shoved up; it's not broken.
 

rstl99

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Oct 31, 2015
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Yes the staff is clearly broken. The roller jewel is fine, it needs to have the old shellac cleaned off and then it needs to be installed properly with new shellac. It just became loose and got shoved up; it's not broken.
Thanks Chris!
Ok sounds like the jewel can be salvaged, good!

Now, as long as this neighbour got me the right balance staff (through his supplier of choice in Canada). I gave him the Hamilton part number I got online (126 for double roller) and made sure to get THAT one. Anyway, I was trying to give him a little job to do, and I don't work much on watches. But sometimes it's best to do it yourself.

I saw Ofrei sell their balance staffs for half the price I paid, oh well, lesson learned.
Cheers.
Robert
 

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