Making tools: top and bottom dies for rivets, these are made from the broken tips of jack hammer bits, the steel is very high carbon and extremely hard to forge with, the spherical depression is created first, with a centre punch, enlarged with a rounded punch and then a 15mm ball bearing beaten into it to get the best shape I could. One sits in the vice, the tool/rivet on that and the top die hammered down on that to fix the work and shape the hot rivet.
