I've searched high and low for a mainspring source, so far to no avail.
I'm measuring 27 wide (3.60mm) 4/0 strength and length 25"

If anyone has any ideas where I can find one I would certainly appreciate it.

No Semca specialists out there?

If I could identify this movement exactly, I might be able to find the proper spring number in my Bestfit catalog. I'm inclined to think a CMH 48.1 might be correct. (3/16 x .009 x 24 hole end)

Hi Dave,

Give the man a call I spoke about, he might be able to help, just a thought.

Best Regards,
Tim