[QUOTE=karlej;1507193]This John Barber has brass pins without collars. They are the original horn scales. It is 182+ years old. No cracks or splits in the horn.

I don't know if it's just me but do I see traces of what was a collar under the head of that pin? I'm not doubting that collarless pins wouldn't crack the horn but it would most likely have to have a tapered hole in the scales I would think.
I have some 1/16" drill bits (.062") plus I have some just a tad larger (.077") which work perfect for pinning & I have never broken a set of scales yet using the .077" drill bits which I found on the bay or any machine shop supply or some tool companies might have them.