I just started rebuilding 18s movements. While cleaning the balance wheel, one of the timing screws fell out. Looks like the pin vices that are needed to reinsert the screw come in different sizes, usually 1, 2, 3, 4, 5, ... Which one do I need for an 18s timing screw? Thanks!

I use a #2 for 16 & 18 size balance screws. You'll find that the screws are different sizes for the same size movements, sometimes even within one balance wheel. #2 is close enough for all in my experience. Other's experiences may vary.

Thanks Douglas, I'll pick up a #2. Saves me from buying a set. Cheers, Jonathan