@david pierce wrote:
Tom,
If you have a microscope check for any flat spots on the pivots and carefully check the jewels to see if the holes are still cylindrical. Make sure the wheel is true and in poise. Make sure the pivot diameter is the proper diameter for the hole in the jewel and check for the proper length of the pivot between the pilar plate and bridge. Make sure that only the cylindrical portion of the pivot is spinning in the jewel hole and that the conical portion is not rubbing on the jewel. Somebody could have relplaced these parts and pressed the jewel in too far and/or made a new pivot and did not fit it properly for the watch. In short, make sure everything fits the way it is supposed to.
david
David:
I have the dimensions from OFrei on the balance staff pivot – to – pivot dimensions. I can figure out pretty closely by micing the plates and jewels to come up with a dimension on the bearing depth. However, when it gets into measuring the jewel oil sinks (and the actual holes as-well-as the amount of depth the pinions should bear into those holes), I’m at something of a loss – actually, it’s more like a black hole than a loss… but none the less.
Do you know where the factory specs can be found for these data? Also, how do you measure the oil sink and pivot bearing dimensions in order to check to see if the ballance staff has the proper jewel to jewel bearing depth?
Oh… the jewels are ok and I put the watch plates back together without any gears or the palet fork, put in the balance cock assembly, and its doing the same thing without anything else installed. Additionally, I tried the same experiment with another balance assembly from a 18s 1883 and it’s doing the same thing. It sure sounds like its a depth issue… but, unless the wrong jewels are installed, I don’t see how that can be, as the jewel pairs are just pushed in and held in place with screws. 
Thanks!
Tom