Spotting & Centering Drills DTN for Spotting Drilling Recommended Cutting Conditions VC (m/min) Material Fr (mm/rev) DTN 90° & DTN 120° DTN 140° Carbon steel 55 ~ 75 60 ~ 90 0.04 ~ 0.14 P Alloy steel 50 ~ 70 55 ~ 85 0.03 ~ 0.10 M Stainless steel 20 ~ 40 22 ~ 50 0.02 ~ 0.10 K Cast iron 50 ~ 80 55 ~ 95 0.04 ~ 0.13 H Hardened steel 20 ~ 40 22 ~ 50 0.02 ~ 0.06 B079