Deep Hole Drilling Tool Steels: D2, A2, S7, O1, and What I've Learned
When I first started deep hole drilling tool steels, I assumed they would behave like the hardened alloy steels I was used to. I was wrong. Tool steels are their own category of misery — high carbide content, through-hardened to the core, and absolutely unforgiving of parameter mistakes. After years of gun-drilling D2, A2, S7, and O1 for mold and die work, here is what I have learned the hard way so you do not have to. ...