Closing a jewel hole

[Murks]

Hi everyone can someone help me please I'm finding it quit difficult to close the small jewel hole on the watch movement after making the hole size bigger to fit my jewel a keep damaging the movement I'm ok with closing the barrel bridge not small hole does anyone knows the type of staking to use so I don't damaged the edge of the holes?

[Waggy]

I assume you mean that your new jewel will not stay in the new hole securely? If that is the case and you can't close it up using the staking set and smoothing broaches (like you would with a barrel arbour hole) maybe you may need to enlarge the hole and insert a jewel with a larger OD (that has an interference fit with the new hole), but the same ID, this time using extra caution not to open the hole up too much. Slow and steady wins the race.

[Murks]

What do you mean with OD and that has a  interference with the new jewel. If a add larger jewel does that not effect the hole size of the pivot will a find same hole size pivot?

[Waggy]

Not necessarily, you may be able to get a jewel with a larger OD but the same ID, maybe if you are fortunate.

[nickelsilver]

If you have a jewel that is a loose fit in the mainplate/bridge, you can theoretically close the hole a bit with a convex punch. But it usually doesn't work that great. Better, as Waggy said, to open the hole to the next size of jewel. So if you have a 1.30mm diameter jewel, and it's loose, open the hole for a 1.40mm jewel (which the reamer in your jeweling tool will do, to the proper interference fit, meaning the hole in the plate/bridge will be 1.39mm). The only thing affecting the hole size of the jewel where it pivot fits is the hole size of the jewel. The jewel in non-compressible. If this were a thin walled bushing in brass, yes, the hole for the pivot might compress a bit, and need broaching to final size once fitted.

 

If the jewel is a loose fit, and the hole won't close enough with a convex punch to hold it, and you don't have a larger jewel to fit, you can make a thin walled bushing and fit it to the plate/bridge, and fit the jewel into that. There's a limit to how thin walled the bushing can be though- about 0.2mm wall thickness. So for a 1.30mm jewel, you would need a bushing with a diameter of 1.70mm. This may be too big for the part you are working on though. In that case, if going the jewel-in-bushing route anyway, it's worth looking for a smaller jewel, so the bushing can be a reasonable size. Ideally you would have a lathe to make the bushing too.

[VWatchie]

4 hours ago, Murks said:

What do you mean with OD

It's simply short for "Outer Diameter", and ID is short for "Inner Diameter".

[Murks]

What's the best convex punch can I Buy online ?

[Waggy]

5 hours ago, VWatchie said:

It's simply short for "Outer Diameter", and ID is short for "Inner Diameter".

Sorry I should not have used an abbreviation, just that quoting IDs and ODs is part of my day job (oil industry), so I'm now hard wired to use that acronym.

[VWatchie]

4 hours ago, Murks said:

What's the best convex punch can I Buy online ?

If I remember correctly, since you're in the UK, cousinsuk.com has a wide selection of punches for your staking set.