Cutting Speed Calculator Formula
Understand the math behind the cutting speed calculator. Each variable explained with a worked example.
Formulas Used
Required Spindle Speed
spindle_rpm = 1000 * cutting_speed / (pi * diameter)Variables
| Variable | Description | Default |
|---|---|---|
cutting_speed | Cutting Speed (Vc)(m/min) | 100 |
diameter | Workpiece Diameter (D)(mm) | 50 |
How It Works
Cutting Speed to Spindle RPM
Cutting speed is the velocity at which the tool edge moves relative to the workpiece surface.
Formula
N = 1000 Vc / (pi D)
where Vc is the desired cutting speed in m/min and D is the workpiece (or cutter) diameter in mm. The factor 1000 converts metres to millimetres. Recommended cutting speeds depend on the tool material and workpiece material combination.
Worked Example
Turning a 50 mm diameter steel bar at 100 m/min cutting speed.
cutting_speed = 100diameter = 50
- 01N = 1000 x 100 / (pi x 50)
- 02N = 100,000 / 157.08 = 637 RPM
Ready to run the numbers?
Open Cutting Speed Calculator