Just recently I have done a couple of cheap pin pallet mechanisms with open loop ended mainsprings. I was having a bit of trouple getting the spring wound up and then trying to tie wire around them so i could then put the mechanism back together, but then, out of the corner of my eye I spotted a cable tie! Oh boy does one of these make the job that much simpler, so much wider than wire and happier to bend to the shape of the spring, and as you tighten the spring you tighten the cable tie, that way if you do lose your grip the spring wont expand that much, you can just continue where you left off