Turning · Released

Turning Speed and Feed Calculator

Calculate spindle RPM, feed rate, and metal removal for CNC lathe / turning operations. Enter workpiece diameter, cutting speed (Vc), and feed per revolution to get the machine settings. For external turning, facing, and boring.

Workpiece diameter — mm

Cutting speed Vc — m/min

Feed per revolution — mm/rev

Depth of cut ap — mm (optional)

Spindle speed RPM

—

Feed rate

—

Actual cutting speed

—

Metal removal rate (if ap given)

—

Formula and use

Spindle speed: RPM = 1000 × Vc / (π × D)

Feed rate: Vf = RPM × f (mm/rev)

Metal removal rate: Q = Vf × ap × f / 1000 (cm³/min)

Cutting speed Vc is the surface speed of the tool relative to the workpiece. It depends on the material combination:

Steel (P): 150–300 m/min with carbide
Stainless (M): 100–200 m/min
Cast iron (K): 80–150 m/min
Aluminum (N): 300–1000 m/min
High-temp alloys (S): 30–80 m/min

Feed per revolution f affects surface finish and chip load. Finish passes use 0.05–0.15 mm/rev; roughing uses 0.2–0.5 mm/rev. Depth of cut ap for carbide is typically 1–4 mm per pass.