Reply To: Pocket watch fault diagnosis

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chris mabbott
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David,

It depends on what type of jewels the watch is fitted with, the two most common are “rubbed-in”, where the jewel is fitted into a custom made brass/gold setting that is sized to press fit into the plate or balance cock. These jewels are then held into the setting by a lip of material left from cutting the recess in the setting center I.D. This lip is then burnished or rubbed over the (underside) outside diameter of the jewel to hold it firmly in place.
There are sets of opening/closing tools especially for this job, or you can also accomplish it on a lathe, takes some practice though.

Type two are friction jewels. A predetermined hole size is drilled into the plate or balance, it is then reamed out, usually with a Seitz reamer, to correspond to the preselected jewel O.D. which is .001 larger than the reamer.
The jewel is then pressed in with the Seitz press. A reading is noted on the micrometer for depth before pushing out and then set to this when pushing in the new jewel.