Unusual Balance...

[captainneek]

Hello, hope everyone is staying safe !

Now, does anyone have any experience with this type of balance ? As you can see from the photo, the roller jewel (missing) is a press fit in the balance arm. To find a suitable jewel will be no problem, but pressing it in ?? 

Any ideas, hints, suggestions will be greatly appreciated.

Mike

[KOwatch]

If I understand roller jewels correctly, it would be fixed with a small amount of shellac, similar to pallet jewels.

 

There's at least one thread on here about a pallet warmer, that's for heating the shellac you would use for this operation.

The split rim on the wheel is an older method of achieving temperature isochronism (stabilizing the balance frequency)

 

Edited February 3, 2021 by KOwatch

[Graziano]

45 minutes ago, KOwatch said:

If I understand roller jewels correctly, it would be fixed with a small amount of shellac, similar to pallet jewels.

 

There's at least one thread on here about a pallet warmer, that's for heating the shellac you would use for this operation.

The split rim on the wheel is an older method of achieving temperature isochronism (stabilizing the balance frequency)

 

Here is Mark's video and a short one on getting shellac ready 

https://youtu.be/TY28dap5Zqg

Edited February 3, 2021 by Graziano

[captainneek]

Hi Graziano, thanks for your reply.

Yes I know about shellac, I use it when and where necessary. However, when I opened this watch for repair, the business end of the jewel fell out of the case...it had broken off. The rest of the jewel was still tight in the balance arm with not a sign of shellac or other adhesive anywhere. This is what makes me think the jewel is a press fit. I've never seen another like this so I'm unsure how to proceed.

 

 

 

[Graziano]

1 hour ago, captainneek said:

Hi Graziano, thanks for your reply.

Yes I know about shellac, I use it when and where necessary. However, when I opened this watch for repair, the business end of the jewel fell out of the case...it had broken off. The rest of the jewel was still tight in the balance arm with not a sign of shellac or other adhesive anywhere. This is what makes me think the jewel is a press fit. I've never seen another like this so I'm unsure how to proceed.

 

 

 

Hi, some watchmakers schools teach this method of pressing a roller jewel, use a tweezer and place a small drop of oil on the face of one of the jaws and place the jewel onto that oiled spot, it'll stick to it fairly well, then just flip it over and press it into the roller. Using the tweezer makes it easier to press the jewel in since you have the leverage from the other jaw against the opposite side of the roller. You could use this the same way on your balance wheel. Tweezers will press the jewel in place, make sure you have it perfectly perpendicular to the balance surface area . Hope that helps you 

Cheers Graziano 

Edited February 3, 2021 by Graziano

[nickelsilver]

Are you sure the old one was broken? Might have just been very short as this is an ultrathin watch.

 

Modern roller jewels may be pressed in the roller, but you won't see it on older stuff and especially not in steel. The interference necessary to hold without cracking the jewel in steel is on the order of 1 micron or so. Already very difficult with round jewels which are far more resistant to breakage than a shaped jewel.

 

It's almost certain that there was a very small amount of shellac in the hole holding the jewel. When you heat it you want what's called a "combination tool" to just heat the center of the balance and not stress the bimetallic rim.

 

If you really really want to press fit you will 100% have to modify the jewel. Ideally it would make the press fit primarily on the flat face and the opposing round surface, avoid the corners.

 

 

[captainneek]

Hello, thanks to you both for your suggestions, both very helpful.

Nickelsilver, yes the old jewel is definitely broken. The lower part fell out when I opened the watch case and the top part was still in the balance arm. You are correct in noticing that the movement is very thin, the balance staff itself is only 2 mm. long including the pivots. The balance arm is only 0.17 mm. thick so there's not a lot of surface area gripping the jewel pin. Maybe best to try shellac first. Where in Switzerland are you (no need to be specific) ? I lived most of my adult life in Lugano.

Thanks again to all three of you who replied and be safe.

 

[nickelsilver]

I'm in Neuchâtel! Been to Lugano but dang it's hard to believe  it's like a 6 hour train ride to the bottom of this little country...

I did a staff for a Piaget 9P a couple of months ago, as I recall the staff was 1.90mm total length and from what I could dig up that's the shortest staff ever used on a commercial movement. So you've got something special there, who's the maker?

 

[captainneek]

Blame it on the Alps !

I have friends in Geneva and that's a ten hour car ride there and back....we don't meet too often. The watch is a "Golay Fils & Stahl", 17''' pocket watch, with a Mueller & Vauchay movement. The whole movement (not counting the sub seconds pivot) is only 2.36mm thick. As a movement it's nothing earth shattering, I've attached a photo.

Cheers, Mike

[nickelsilver]

Wow that's super! Haven't seen one of those. Hope the mainspring is ok- doubt there's anything in the Generale Ressorts catalog for that !

[captainneek]

The mainspring seems ok, Cousins UK has one that is useable so I'll change it anyway. The staff will be an interesting challenge though. I can't imagine how the pivots and the roller jewel got broken, there's no other damage to the movement or to the case.

 

[captainneek]

Sorry for the phonetic spelling mistake, of course that should be "Mueller & Vaucher"