INSTITUTE OF
MACHINES
CNC Machining
3D Printing
Materials
Automation
Shop Tools
Spindle Speed Calculator (RPM)
Cutting Speed (SFM)
Surface Feet per Minute. E.g., Alum=400-800, Steel=100-200.
Tool/Part Diameter (inch)
Calculated RPM
Calculate via Server
Formula
RPM = (SFM × 12) / (π × D)