Can someone out there tell me how & why you would use these tools. I have two of them that came with some late collets. I understand that the balance does not have to be taken apart, time saver?

But, if I am looking at this correctly only the end of the balance staff pivot is exposed beyond the shield. Is it just for rounding or flatening the staff end?
So far I have not seen a reference in any book as to how they are used.

Thanks

Bob,

Balloon chucks are very useful for polishing pivots. I wouldn't use them for attemting to straighten a pivot.

Make sure they are in good shape before using.

I think they can be found in the Goodrich book as well as Perkins.

The ones you posted are very close to the ones I have. I guess I'll have to practice with these.

Today I remove the roller table and hairspring and polish free hand. I have had good luck so far.

My watch mentor instructed to put the staff and balance wheel back in the movement after staffing or polishing and test the freedom in all positions. If it checks out okay then mount the roller table and hairspring.

Thinking about it futher, if one is to test the freedom the hairspring and roller table would be in the way? Maybe these chucks will go up for sale.

Thanks for the post!

Bob,
You could always test without the pallet in. I would hang on to the chucks. You might change you mind someday.
Scott

In the last 200 or so watches, I have used a Balloon chuck 4 or 5 times to polish a pivot that is slightly damaged by a cracked or broken jewel. Risking the Balance wheel assembly by removing the Hairspring and the roller(s) is only a "last resort" if the Beat Timing is uncorrectibly bad (>10 Msec RR, 30 mSec others) making it clear everything is messed up.
Keep those Balloon chucks. They work quickly and safely for pivot polishing.

Thanks Guys, I'll take your advice and hold on to them.

Hello All,
I'm a newbie here and would like to ask if anyone could please explain to me how one uses the balloon chucks to polish pivots. A photo or video of one in use would be great, but even a description would help. Is the polishing done with a file? If so do you support the backside of the pivot? What kind of speed on the lathe, or do you even run the motor?

If it's really bad I use a fingernail file to smooth it into shape on the lathe, then I will switch to a very fine stone and finally a piece of leather glued to a stick. Some times I will use fine grit automotive rubbing compound on the strip of leather. Remember to clean the leather when you are done.

Yes Dave, having trouble with this visualization also .
It seems like the pivot is inserted in the balloon, with the small end protruding out the end?
This is a page from "the watchmakers lathe" by Goodrich and is free online.