I want to make a plug gauge using O1 tool steel. I am going to harden,
grind and lap the gauge and knurl the handle. So if I harden the entire
piece, how do I get the scale out of the knurls? Or do I heat the entire
piece, only quench the plug end, let the handle cool slowly keeping the
handle annealed, remove the scale and knurl? Or do I not have a clue what I
am talking about?

Jeff Lindemuth