Greasy Roller

The roller jewel, or pin, sticks out vertically down from the roller table on the middle of the balance wheel.  My photo here of that is pretty hard to see unfortunately.

Anyhow, this watch had an odd irregular beat problem, and I finally realized that the roller jewel was loose.

The jewel is held in place with shellac.  The part is heated with an alcohol lamp, while held in a certain tool, the shellac melts, and when it cools, it hardens and holds the jewel.  Getting the temperature right is a matter of experience.  Too hot and the shellac scorches.  The roller jewel, which has a 'D' shaped profile, also must be perfectly straight and square to the balance staff.  One gets very little time to move it before the shellac cools and firms up.

This shellac looked OK, so I tried, several time, just heating and re-seating the jewel.  It just stayed loose.

Finally I realized that someone previously had used what actually seemed to be some sort of wax (?!) on the roller jewel, which is why it was loose, and why new shellac would not stick to the resulting oily surface of the jewel.  I had to disassemble the thing again and hand clean the jewel and the roller table with acetone.  That did the trick, the jewel is now secure.  On to the next issue...

My Grandfather always said you never know what you're going to find when you open up a watch.