Need to replace a rubbed in jewel, can't find any candidates that are a comparable size.

[GregG]

I have a watch that uses a rubbed in jewel for the seconds wheel.  At some point in the past, the jewel must have broken, and the person repairing it replaced it with a regular friction jewel that is 1.2 mm OD, 0.3 mm thick, and with a hole that can accommodate a 0.215 mm pivot (so I'm assuming the ID is roughly 0.24 mm).  He did not properly modify the setting to use the friction jewel, he just shoved the friction jewel into the rubbed-in setting.  I'd like to do the repair properly, which means grinding down a friction jewel with diamond paste in order to add the chamfered edge https://www.youtube.com/watch?v=j3gxp96WjCI.  The problem is, I can't find any comparable jewel to use, or at least any that are still in modern production.  For this reason, I don't want to modify the replacement friction jewel; if I mess up, I'm out of luck.

The best candidates I've found are either the correct OD, and an incorrect ID, or vice versa.  The closest one that Cousins has is 0.80 mm OD x 0.25 mm ID; much too small on the OD.  The closest one that I could find on AliExpress is 1.2 mm OD x 0.3 mm ID; much too large on the ID.  Ofrei looks like it has 24/120 jewels in stock, but they're $13 a piece vs modern production jewels which are ~60¢ if I buy them from Cousins or ~$1 if I buy them from AliExpress.

So, asking for advice, what should I do?  The watch is running with the modern friction jewel.  Should I abide by the "if it ain't broke, don't fix it" rule, or should I buy a few sizes and see what works best?

 

Edited February 20 by GregG

[SwissSeiko]

If youre comfortable modifying a jewel to add a chamfer, why dont you just get a jewel with the correct ID and then adjust the OD of the jewel? You will need a diamond wheel, and it should be done wet. 

[GregG]

4 minutes ago, SwissSeiko said:

If youre comfortable modifying a jewel to add a chamfer, why dont you just get a jewel with the correct ID and then adjust the OD of the jewel? You will need a diamond wheel, and it should be done wet. 

Do you have a source that I could refer to to see the process?

[SwissSeiko]

2 minutes ago, GregG said:

Do you have a source that I could refer to to see the process?

It is referenced in George Daniels book. I dont take enough photos when I am doing a repair. Do you have a lathe? I can lay it out for you very easily if you do

[GregG]

Yes, I do have a lathe.

[GregG]

Just realized, the jewels that have an acceptable ID all have too low of an OD, so I can't grind anything down.  The ones with an acceptable OD have too low of an ID.  So I was thinking, can I take a 0.25 mm drill bit, load it with some diamond paste, and attempt to grind through the center of the jewel to widen it?  I know the jewel is harder than the drill bit, but the drill bit would merely serve as a method of conveying the diamond paste directly to the center.

[HectorLooi]

I doubt that you can get the inside of the hole as smooth as the factory can.

But please try it and let us know the progress.