Spindle Turning Speed Calculator

Maximum RPM from workpiece diameter and material.

Workpiece diameter (in)

Workpiece length (in)

Material (0-4)

Lathe max RPM

Tab to move between fields

Roughing RPM

3,000

Finishing RPM

3,600

Adjusted roughing RPM3,000

Roughing SFM1,571

Finishing SFM1,885

Slenderness ratio6

Needs steady rest? (1=yes)0

Tailstock Critical1

How to Use This Calculator

How the result changes with Workpiece diameter (in)

Workpiece diameter (in): Largest diameter of the spindle blank.
Workpiece length (in): Overall length of the spindle.
Material (0-4): 0=Hardwood, 1=Softwood, 2=Green/wet, 3=Spalted/punky, 4=Resin/acrylic.
Lathe max RPM: Maximum RPM your lathe can achieve.

Roughing RPM: Recommended RPM for roughing cuts (6000/diameter rule, adjusted for material).
Finishing RPM: Recommended RPM for finishing cuts (9000/diameter rule, adjusted for material).
Adjusted roughing RPM: Roughing RPM reduced for slender workpieces prone to vibration.
Roughing SFM: Surface speed in feet per minute at roughing RPM. Ideal: 700-900 SFM.
Finishing SFM: Surface speed at finishing RPM. Ideal: 900-1200 SFM.
Slenderness ratio: Length/diameter ratio. Above 6 needs care; above 10 needs a steady rest.
Needs steady rest? (1=yes): Whether the workpiece is slender enough to benefit from a steady rest.

Identify Input Parameters
4 parameters
Workpiece diameter (in) = 2, Workpiece length (in) = 12, Material (0-4) = 0, Lathe max RPM = 3600 = 4 input(s) provided
Calculate Roughing RPM
Roughing RPM = min(roughingRPM, latheMaxRPM)
3000 = 3000
Calculate Finishing RPM
Finishing RPM = min(finishingRPM, latheMaxRPM)
3600 = 3600
Calculate Adjusted roughing RPM
Adjusted roughing RPM
3000 = 3000
Calculate Roughing SFM
Roughing SFM = (π * diameter * clampedRoughing) / 12
1571 = 1571