Our Reaper cobalt, 135 degree split point, half inch reduced shank Silver & Deming drill bits are particularly successful in cutting holes in harder grades of stainless steel and other material higher up on the Rockwell chart. Our patented M42+ alloy contains a higher cobalt percentage than the industry standard of 5-8 percent cobalt, rendering them super-friction-resistant and will cut more holes than most of our competitors, making the need to re-sharpen less frequent. And unlike conventional Silver & Deming bits with round shanks, all Reaper Silver & Deming bits have three ground flats, preventing chuck slippage.