Technique for threaded barrel arbor?

[MrRoundel]

I'm working on an early 1900's Vacheron 12''' ligne movement. I took my time with servicing it and everything went well. As I often do with my own oldsters, I left the mainspring alone. If it's just going to sit in a cabinet or movement holder, I'm not super concerned about perfectly strong running. However, this little V&C ran great, but only for a short time. So I ended up pulling the barrel to look at the mainspring. It looked OK, as much as one can tell when it's still in the barrel, but when I pulled it out of the barrel, I saw it was very badly "set". After a few bad experiences, I'm a bit loathe to mess with Swiss barrels that have the threaded arbor. But on this one I have to.

Does anyone have any tips for holding the catch side inside the barrel while one turns the arbor from the deeper square side? There are two holes on opposite sides of the center that look like there must be a special Swiss arbor tool, like a small snap-ring plier, to work with them. I have read that one can use brass lined pliers to hold, but I don't have those. It's a nice Vacheron, so I'm really trying to leave as few marks as I can on parts. I've already put a few scratches inside the barrel while trying to unscrew the arbor.

If I don't have success getting the arbor to separate, perhaps I can pop the mainspring in with the arbor already in place? It seems possible, but perhaps a bit tricky. Any help is appreciated. Cheers.

 

 

Edited March 22, 2018 by MrRoundel
spelling

[oldhippy]

You could use tweezers grind them down so they just fit in the holes, that way they would not slip out and mark the barrel.  

[MrRoundel]

6 hours ago, oldhippy said:

You could use tweezers grind them down so they just fit in the holes, that way they would not slip out and mark the barrel.  

 

Thanks, oldhippy. I started to do that with my best tweezers, but thought better of it. That's a good idea to use one of my older, or at least cheaper, sets of tweezers in the way you suggest. I'll give it a shot. Cheers.

[MrRoundel]

Well, gave it a shot with the tweezers. There seems to be too much flex in the tweezers, given how tight it is. I'm using a multi-sized bench key to hold onto the square end (non-stopworks side). It holds, but does seem a touch too big. I guess I'll have to get the right sized key and give it another shot. I'll keep trying, no matter what. Thanks again.

 

[MrRoundel]

Well, it was really on othere. I ended up looking in my pliers drawer, and found a vise with a sliding tightener on it. It has bailed me out before. I was able to grab the sides, away from the spring catch, tighten with sliding loop, squeeze a bit tighter by hand, while I loosened with the multi-sized bench-key. It got it, but barely. Now to find the right mainspring. Speaking of that, it measures around 1.68mm wide and .12mm thick. The only springs I see are widths of 1.65mm and 1.70mm, nothing in between. It does look like there should be just enough room for the 1.70mm, but perhaps a 1.65mm would be the safer play. Hmm...