Ordering replacement friction fit jewel

[jnash]

I have a old lemania chrono with a missing jewel. It looks like the hole diameter is 28 using the seitz guage and I have found a jewel (with wrong hole size that goes in well that is 1.32mm.

Therefore looking for a jewel around 1.32 outside diameter  with a 0.28 hole.

Looking at cousins they only do a outside diameter of 1.30 or 1.40..

 

They happen to be obsolete (great) to try them anyway but am I correct in thinking that if the 1.30 doesn't work I will have to get a 1.40 and modify the hole of the plate ? 

 

Hope the above makes sense. 

 

Thanks in advance .

 

J

[watchweasol]

Hi  before resorting to broaching the plate have a look at the likes of Gleave&co AG Thomas and even the American sites  Jules Borel, Esslinger, and Perrins in Canada. The thing being once the hole is opened out going backwards is not an option, check out these other guys then if a negative you only have one choice.

[Nucejoe]

Agree with the above.  Chrono Lemania is worth the search. There are several options,  used parts or interchangable you didn't think would fit.

What caliber is it?  What wheel?   On some  high torque arbor  you may make a metal bush fit. 

 

 

[nickelsilver]

Jewels come in 0.10mm increments, no in betweens. The exception is older bezel set or "rubbed in" jewels, these can vary from a little to a lot. Can you post a pic of the underside of where the jewel goes?

[jnash]

Sure

Attached are pics of the mainplate , thanks in advance

Sent from my ONEPLUS A6003 using Tapatalk

[saswatch88]

To measure the opening may take some skills since a caliper will not work. Maybe a round broach and then measuring the diameter of the spot on the broach. Then order a jewel that is bigger like the 1.40 because its always better to go bigger then broach as needed or use a jewel setting opener. Too small there is nothing you can do. You could get the 1.30 and use a jewel closer to spread the metal out a bit To set it in, but option 1 is better. in order to do this you will need a vintage jewel setter kit with openers and closers. If you don’t have one then only option is using a broach get a cutting and smoothing.

Edited December 31, 2019 by saswatch88

[jdm]

To the surprise of many here, it was shown jewels can be ground to size and someone here manages to do that without a real lathe. Give a look to the last postings in the below. That being said with just a 0.02mm difference I think the plate hole can be closed to hold good.