Here is what can happen when a damaged jewel runs on a pivot.

Jewel that did the damage.

Picture perfect proof about NOT running a 'found' watch before having it checked over and COA'd by a competent watchmaker.

Regards! Mark

I'm surprised it ran at all.

Hard to tell from the pictures, but it looks like the extreme tip of the staff has some curve to it. Therefore, I would not think you could rule out some form of impact that might have caused the initial damage to the jewel, and the balance still being able to freely move in the jewel causing the grooves in the pivot of the staff... Did the movement run in all positions?

Love these topics and pictures - keep them coming !!

Great instructional pics.

And as far as balloon chucks go... so far, I find the balloon chuck to be painfully awkward to use. It is easier for me to pull the hair spring and rollers and chuck the staff in to a collet than to use a balloon chuck.

While some damaged pivots are recoverable as Dave suggests, not this one. The pivot is actually cut about halfway thru its diameter by the ragged edge of the broken jewel. This watch was still able to run in all positions, albeit not very well. This is a customer's very nice Sangamo into which I will be installing a new staff and foot jewel.