Examples
Examples
Try the starting example
- Drill cutting diameter (mm)
- 10
- Supplier cutting speed (m/min)
- 100
- Spindle speed (rpm)
- 3,183.098862
- Nearest whole rpm
- 3183
Try another scenario
- Drill cutting diameter (mm)
- 20
- Supplier cutting speed (m/min)
- 60
- Spindle speed (rpm)
- 954.929659
- Nearest whole rpm
- 955
Calculation method
Calculation method
Spindle speed (rpm)
1000 × cutting speed in m/min / (π × cutting diameter in mm).
Nearest whole rpm
Round the mathematical spindle speed to the nearest whole rpm.
Symbols and units
- a
- Drill cutting diameter (mm)
- b
- Supplier cutting speed (m/min)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- Converts a supplier-provided cutting speed and actual cutting diameter into rpm. Does not select speeds for a material or approve machine/tool limits; a rounded value is not a validated machine setting.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
Sandvik Coromant: drilling formulas and definitions ↗
Background reading; this does not imply endorsement or independent review of SumFizz.