How do you convert cutting speed?
Spindle speed is n = (vc × 1000) / (π × D), where vc is the cutting speed in m/min and D the diameter in mm. Feed rate is vf = fz × z × n (feed per tooth × number of teeth × spindle speed). Pick vc based on material and tooling — carbide handles higher values than HSS.
Frequently asked questions
What is a good cutting speed for steel?
With carbide, vc for structural steel is roughly 120–200 m/min, lower for stainless (80–140 m/min). With HSS the values are about 3–4× lower. Always check the tool maker’s data.
What is the difference between vc and n?
vc (m/min) is the speed at the cutting edge and depends on material and tool; n (rpm) is the spindle speed, derived from vc and the diameter.
Does this apply to milling and turning?
Yes. For milling, D is the cutter diameter; for turning, the workpiece diameter. The formula is the same.