Barrel arbor fitting into the mainspring

Nednico · July 12, 2019

Hello there !

I'm facing a problem fitting the barrel arbor into the mainspring. I've just changed the mainspring for a brand new one, from generale ressorts and I have difficulty to insert the arbor, the spring end is very tight.

Any suggestion because I'm afraid to break the spring or damage the barrel or arbor.

Thank you.

Nico

nickelsilver · July 12, 2019

Grab the arbor in a pin vice (or barrel arbor holder, which is a specialized pin vice for just this task), then twist it in, in the opposite direction of winding.

PeterS · July 12, 2019

If you have a casing cushion or something similar place the barrel with the spring on the cushion before you attempt to fit the arbor in. It’s very soft in the middle and you will need this for the arbour to go in all the way. Otherwise your mat/desk will prevent you from pushing the arbor all the way down.

MrRoundel · July 12, 2019

When I face a stubborn arbor/spring pairing, I use a collet-holding pin-vise, with the barrel held on top of a piece of round pithwood with a hole in the center. Granted, the collet-holding vise may not be an easy get, but I suppose a large pin-vise would work just as well.

With two-piece Swiss arbors, I have used a pointed piece of pegwood to keep the arbor centered as I manipulate it into the inner coil with the back end of brass tweezers. Good luck.