Removing material from an already poised balance rim.

[Nucejoe]

I am sure my three spoke balance wheel is already poised but I need to remove material off the rim to reduce weight.

I wonder, If I remove  material off the rim at the end of each spoke ( hopefully same amount of material ) would I have violated classical watchmaking practice, is this approaxh  acceptable?  what is the norm? 

Picture, courtesy of a fellow forum member, oh what a mess. 

[JohnR725]

9 hours ago, Nucejoe said:

I wonder, If I remove  material off the rim at the end of each spoke ( hopefully same amount of material ) would I have violated classical watchmaking practice, is this approaxh  acceptable?  what is the norm? 

It depends upon who you ask and which discussion group you're asking.

Then on a modern balance wheel like what you have there isn't really a procedure. As normally wouldn't have to do what you're asking to do. Usually the balance wheels are relatively hard so I would use a carbide drill. Then do the same as they did when their poising just cut the rim on the underside no one will see what you ever did.

 

 

[nickelsilver]

Sounds like you have a mismatched balance/hairspring? I had a case like that on a vintage piece for a big manufacturer. Even they don't have spare parts for this caliber; they sent the watch with a bare balance and a bare spring, said do what you can. Solid balance, luckily the rate was too slow, I think I had to put about 5 opposing hole pairs (10 holes) to get it to rate. It was a pain, as even though I did it with a precision machine, you never really know how much you took and 0.01mm more or less deep will throw the poise off. So it was drill, check rate and dynamic poise, drill, check rate and dynamic poise, again and again. But it did work, and the watch timed within spec (I think 15 seconds delta in 6 positions).

 

That looks like a nickel balance, should drill fine with high speed steel (normal) drills. Glucydur really does need carbide.

[Nucejoe]

6 hours ago, nickelsilver said:

Sounds like you have a mismatched balance/hairspring? 

Yes, Actually a bunch of same caliber balance completes some with broken pivot some ruined hairsprings. 

Usualy a few  just match  without having remove material, the luxury of having a bunch to match up.

Thanks for your response.