Hardening O1 drill rod with a torch Practical Machinist
2014 03 04 nbsp 0183 32 The usual is to clean up a spot on the part and evenly heat with the torch again to the right temper color Straw for full hard beyond if you need less hardness and less brittleness but dont overdo it Online should have some color temper charts O 1 I do right away after quench cool I ve seen it crack untempered JinNJ 03 05 2014 12 21 PM 7