Don't get the white heat on the surface only.
Don't hurry your heating for hardening; let the heat soak thoroughly through the nose of the tool.
Don't melt the nose of the tool.
Don't, as a rule, dip the nose into water; this should be done only for extremely hard material. It is dangerous to put the nose into water for fear of cracking and when you do put the nose into water put just 1/2 in. only of the extreme white hot part into the water and don't keep it too long in the water; just a few seconds, and then harden in oil. We do not recommend water hardening.
Don't grind too forcibly.
Don't grind dry after hardening.
Don't discolor the steel in grinding.
Don't give too much clearance on tools for cutting cast iron.
Don't start on cast iron with a razor edge on the tool. Take an oil stone and wipe three or four times over the razor edge.
Don't use tool holder steel from bars without hardening the nose of each individual tool bit.