Interestingly, a good pair of tinsnips is enough. It was a serious problem until Isaac Newton (of all people) came along. Apologies that I can't find a better

Interestingly, a good pair of tinsnips is enough. It was a serious problem until Isaac Newton (of all people) came along. Apologies that I can't find a better source right now: http://www.lsned.com/newton-invented-ridges-coins/ http://www.lsned.com/newton-invented-ridges-coins/