tight fit for barrel arbor - help!

[DanB]

Just put a new mainspring into the barrel of a Hamilton 661. The end where the barrel arbor gets installed is very tight making it very difficult to squeeze the barrel arbor in. I'm afraid to try to spread that end of the mainspring with tweezers to enlarge it, and it's very difficult to do at any rate. I've done about 20 mainsprings so far without a problem using my tweezer holding the barrel arbor and working it in. Any suggestions for how to squeeze in a barrel arbor on a tight mainspring end? Thanks

[nickelsilver]

Grab the arbor with a pinvice or barrel arbor holder (really just a glorified pinvice) and turn clockwise while keeping firm pressure against the spring. It should open up and take the arbor.

[DanB]

That worked - thanks so much!