A browser-only calculator showing how a cutting-speed increase changes tool life, tool-changShort answer: at a Taylor exponent of n = 0.25, a 20 % speed increase leaves roughly 48 % of the original tool life, because life scales with Vc−1/n. The calculator below turns that into tool-change stops and good parts per hour, so you can see whether the extra removal rate survives the stops before the program reaches a machine.e stops and good parts per hour on high-strength alloy steels.