There are three tool options to consider when drilling large-diameter holes in thick steel: twist drill bits, hole saws and annular cutters. 1. Twist drill bits. Especially in steel thicker than ¼", ...
Most metal drill bits are designed to 'grind' when drilling through metal, creating a slow and low-quality hole. Diablo's Metal Demonâ„¢ Drill Bits for Mild, Hardened and Stainless Steels are ...