That first Anonymous posting was me folks - as noted square shank tacks were used exclusively intil sometime around the early 1870's maybe late 1860's. After that you get a mix of both the square shanks and the iron/steel shank tacks.
The Trunkshoppe is still the only source I know for proper square shank tacks (ebay and other places sometimes sell old originals). Two caveats - they are bronze not brass, but it's a good yellow bronze that looks appropriate. Second they are VERY soft so care must be taken in pre-drilling, and by using either a concave headed setter or a concave "anvil" or the head will flatten out completely when peening the shank.
Tandy leather cap headed rivet tools work fine for the 7-8mm sizes which come cloeset to the early 1/4-5/16" headed tacks whihc were the most widely used size. The only other thing is they are much more expensive in comparison to iron shanks. I give my customers the choice but when doing something like a tack belt (I've used from 200-600 tacks on some belts) the cost can go way up real fast.
