How does this jewel stay in

[Lc130]

Hi All

I'm a beginner.  This center wheel bridge jewel fell out of the bifora 115/1 in the wash.  Is it just held in place by the wheel that sits on top (third)?  I'm wondering if it was pressed in.

Thank you

Charlie

Thank you

[nickelsilver]

It should be pressed in, friction fit. That it fell out means the fit is too loose, tricky to tighten that hole there but you should try

[Lc130]

3 minutes ago, nickelsilver said:

It should be pressed in, friction fit. That it fell out means the fit is too loose, tricky to tighten that hole there but you should try

How would I tighten it?  I have two biforas and ran both bridges through the cleaner and jewels fell out of both.

[jguitron]

Oh boy... jeweling is a complete topic or master skill in its own right. I’d say pretty advanced although it is straightforward. 
 

Jeweling tools are common anywhere watchmaking tools and parts are sold. Seitz made great sets. HOWEVER, nowadays there is the one and only Horia tool. This provides you with amazing precision to adjust the level of the jewel within the hole. After all, ENDSHAKE is what makes it breaks how a watch runs and the adjustments need be very precise. 
 

Anyway, the jewel hole is measured and a jewel 0.01mm bigger is chosen. You have to determine what kind of opening the jewel should have as there are several options but once chosen, the horia tool (or any jeweling tool for that matter) will let you friction fit it in place. Then you have to check endshake and adjust accordingly. The precision of the horia tool comes in handy when you have a cracked jewel that is still in position, so you can measure exactly how deep it is and when the replacement is pushed in, it’s left at the exact same height. 

Anyway, it may be that the brand chose slightly smaller jewels than ideal therefore allowing them to come out with the wash. As you may imagine, such loose fit would also allow the jewel to move with a mild impact that the watch would get, throwing things in disarray. 
 

I hope this helps. 
 

Good luck!

[Lc130]

Thank you both for the quick response.  I'll have to add jeweling to my learn list.

[Tmuir]

If you do decide to buy a jewelling tool and buy a second hand one make sure the press part itself is in good condition, don't be worried if a few reamers or pushers are missing as you can buy replacements for them for reasonable prices, but the press itself is expensive.