Cutting Speed & RPM Calculator
Spindle RPM from surface speed and diameter — lathe, mill and drill.
The machinist's first calculation, every job. HSS drill in mild steel: ~25 m/min → a 10 mm drill wants ~800 rpm. Too fast burns tools; too slow rubs and work-hardens.
Formula
Cutting Speed & RPM Calculator is a free cutting speed rpm for mechanical and machine-design engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Cutting Speed & RPM Calculator
Spindle RPM from surface speed and diameter — lathe, mill and drill. The calculation implements N = 1000·V_c/(π·D) (US: RPM = 3.82×SFM/D_in) (Machinery's Handbook — speeds and feeds). The machinist's first calculation, every job. HSS drill in mild steel: ~25 m/min → a 10 mm drill wants ~800 rpm. Too fast burns tools; too slow rubs and work-hardens.
How to use Cutting Speed & RPM Calculator
- 1Enter Cutting speed in m/min (HSS/steel 25–35 · carbide/steel 100–200 · alu w/ carbide 300+).
- 2Enter Work/tool diameter in mm.
- 3Read Spindle speed instantly — no submit button needed.
- 4Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Cutting Speed & RPM Calculator?
- ✓Implements the standard formula — N = 1000·V_c/(π·D) (US: RPM = 3.82×SFM/D_in)
- ✓Reference cited on-page: Machinery's Handbook — speeds and feeds
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Cutting Speed & RPM Calculator use?+
It computes N = 1000·V_c/(π·D) (US: RPM = 3.82×SFM/D_in), per Machinery's Handbook — speeds and feeds. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
The machinist's first calculation, every job. HSS drill in mild steel: ~25 m/min → a 10 mm drill wants ~800 rpm. Too fast burns tools; too slow rubs and work-hardens.
Is this suitable for machine design coursework?+
Yes — these are the exact Shigley/Machinery's-Handbook formulas, with the substitution shown step by step, so you can follow the worked example into your own calculation sheet.
Is the Cutting Speed & RPM Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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