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RPM to Cutting Speed Calculator
Enter diameter plus either RPM or cutting speed โ the other updates instantly.
Formula
Vc = ฯ ร D ร n รท 1000 (m/min) | n = Vc ร 1000 รท (ฯ ร D)
Typical Cutting Speeds (m/min)
| Material | HSS tool | Carbide tool |
|---|---|---|
| Mild steel | 20โ30 | 90โ150 |
| Stainless 304 | 15โ20 | 60โ120 |
| Aluminum | 80โ150 | 300โ800 |
| Cast iron | 20โ35 | 100โ200 |
| Titanium | 10โ18 | 40โ80 |
FAQ
What is SFM?
Surface feet per minute โ the imperial cutting speed unit. 1 m/min = 3.281 SFM.
Why does RPM change with diameter?
Cutting speed is measured at the tool edge; a bigger diameter covers more distance per revolution, so it needs lower RPM for the same Vc.