Methodology
Formulas
RPM = (SFM x 12) / (pi x diameter in inches)
RPM = (m/min x 1000) / (pi x diameter in mm)
Feed rate = RPM x chip load per tooth x number of flutes
Drill feed rate = RPM x feed per revolution
Material removal rate = feed rate x width of cut x depth of cut
Power = material removal rate x unit power
Sources
The formulas are standard machining equations found in public textbooks and tooling manufacturer handbooks. The material surface speed and chip load values are rounded from commonly published starting ranges for carbide and HSS tooling.
- Machinery's Handbook (Industrial Press), speeds and feeds section
- Public manufacturer engineering resources for surface speed and chip load starting points
- Unit power values are common approximations of power per unit material removal rate
What editorial estimate means
Values on this site are editorial estimates, not lab calibrated data. They are rounded and simplified for quick reference and may not reflect your specific tool geometry, coating, machine rigidity, workholding or coolant. Always defer to your tooling manufacturer and machine manual.
Safety
This tool cannot guarantee that a cut will be safe or that a tool will not break. Cutting can cause injury. Verify spindle power, workholding and coolant, use proper guarding and personal protective equipment, and start with conservative parameters.