I'm new to the forum and need some help. I purchased a real nice Illinois grade 405 size 12s model 3 which was running slow. I thought it just needed service but to my chagrin, the lower balance jewel cap is cracked. My issue is I have never changed a jewel cap and don't know how to order or measure for a replacement. I searched on line and I guess I need a pivot hole size which is foreign to me as to the numbering system. I do have a micrometer that I can measure in thousands of inch and the same with the jewel cap bushing. Both upper and lower balance staff pivots appear to be OK. Not sure how the cap was cracked but the watch was made in 1927. I did notice a very small dent on the case back that was hammered out so good possibility it was dropped. Any recommendations would sure be appreciated as I'm just a hobbyist fixing my own watches. I do have a poising tool but recommendations for other repair tools are sure welcome. I'm not confident yet for balance staff repair.
Thanks in advance,
Rob

Rob

First of all, welcome to the forum!

I see that your question has gone unanswered, so I'll take a shot at it. Just to be sure about terminology, are you referring to the cap jewel that is on the dial side of the movement? Note that if it is the cap jewel, you don't need to worry about pivot size, since the cap jewels don't have a hole in them - the end of the pivot runs on the surface of the cap jewel. To find a replacement, measure the diameter in mm of the setting that the jewel is in, plus the thickness of the setting. Someone should then be able to match up a replacement for you.

Regards

Doug

Hey Rob! I just saw this post. I may be able to help! Do you need a cap and a hole jewel?