Hi, I just picked up a 992 serial number 2486353 with a broken balance staff. Can anybody please provide a part number, not quite sure which one I need from looking in the catalogs. Thanks

Hi William,

Staff 434. You will have to determine if it has a small or large collet as the 434 comes both ways. The majority I see are the small collet, but there are some of the large collets out there. Also there are at least a couple of pivot sizes so keep that in mind.

Rob
www.pocketwatchrepairs.net

Thanks, could you elaborate on pivot sizes that has me confused. Do their numbers correlate to a certain diameter?

William the 434 staffs came in pivot size 10,11 and 12. Of course you would want to match up these pivot sizes with a corresponding balance hole jewels of the same size for proper fit. A pivot to large for a balance jewel hole clearly would cause the watch not to run because of the tight fit. Any time staffing is done the staff should be pre tested for fit before installation. In the long run this will save a good amount of time on the job.

Rob
www.pocketwatchrepairs.net

Thanks for the information, I never realized that the staffs came in different diameters. I learn something new every time I come here!

The 10, 11 and 12 are the pivot sizes of the balance staffs and it is not unusual for most balance staffs to have a couple (or more) different pivot sizes.

Rob
www.pocketwatchrepairs.net