Getting the right Roller Impulse Pin Jewel

[ColinC]

Hello,
I have an ETA 2782 movement that is missing its roller jewel.  I see loads of different jewels for sale out there but I haven't found anywhere that lists which one is right for this movement.  And since I don't have the old jewel I can't measure it! - I guess I could try and measure the hole but I don't really have the right tool..  What is the right tool?

What is your experience of packs of assorted jewels? - are the right ones ever in there or are they not even worth searching through?  I am thinking for this and in general for having a some spares for when I find cracked jewels.

Previously I have stolen a corresponding jewel from a donor movement if ever I need to replace a jewel.  This has allowed me to avoid trying to identfy the right jewel. - Again I have no idea how to tell what size or if I should choose "Flat Cylindrical" or "Flat Olive" and tools and techniques for measuring - so any pointers would be welcome!

[mikepilk]

I would just replace the roller (part #730).  Look here   http://cgi.julesborel.com/cgi-bin/matcgi2?ref=ETA_2770 

and select 'Roller', and you will see it's common to about 100 movements. 

I just found one. If you do an ebay UK search for "NOS - ETA - Various New Movement Parts", in the drop down list is 2783-730. A roller for cal 2783 which is the same as for your movement.

Edited March 15 by mikepilk

[JohnR725]

18 hours ago, ColinC said:

I guess I could try and measure the hole but I don't really have the right tool..

on a modern watch it's easier to just replace the entire roller assembly.

If you're dealing with a pocket watch you would measure the slot in the four core the roller jewel goes. The other variety of measuring tools this is one of

then some examples of using the tool

[ColinC]

Thanks for the input - I have a new (to me) staking set and had been reading and watching videos on removing and replacing roller tables.  Since this will be my first time doing that I think that your suggested route sounds a much better idea and increases my chances of success if I don't combine it with my first effort at using shellac!