HRC65 Thread Mill RPM Selection Guide: Optimizing Speed for Precision Hardened Steel Threading
Two weeks ago, a German mold-and-die client emailed our technical desk photos of scrapped SKD11 stamping inserts. The job called for M4×0.7 blind-hole threads at a verified hardness of 64–65 HRC. The failure was immediate: the tool snapped inside the second hole. Its cutting edges showed severe shell-like micro-chipping, leaving carbide fragments buried inside a