Loading
One moment.
Reading the spec sheet
One moment.
These are the HSS and carbide starting ranges stored in the ShopCalc material library. The RPM table applies the site’s SFM-to-RPM formula to each range.
RPM is computed at the low, midpoint, and high end of both stored SFM ranges. Diameter is the cutter diameter for milling or cutting diameter for turning.
| Tool diameter | HSS RPM | Carbide RPM | ||||
|---|---|---|---|---|---|---|
| Low · 32 SFM | Mid · 43.5 SFM | High · 55 SFM | Low · 162 SFM | Mid · 245.5 SFM | High · 329 SFM | |
| 1/8″ | 978 | 1,329 | 1,681 | 4,950 | 7,502 | 10,053 |
| 1/4″ | 489 | 665 | 840 | 2,475 | 3,751 | 5,027 |
| 3/8″ | 326 | 443 | 560 | 1,650 | 2,501 | 3,351 |
| 1/2″ | 244 | 332 | 420 | 1,238 | 1,875 | 2,513 |
| 3/4″ | 163 | 222 | 280 | 825 | 1,250 | 1,676 |
| 1″ | 122 | 166 | 210 | 619 | 938 | 1,257 |
The existing SFM-to-RPM calculator is preset to Tool Steel (S7), a 1/2-inch tool, and the 43.5 SFM HSS midpoint. Change any input to recalculate.
The stored starting range is 32–55 SFM for HSS tooling and 162–329 SFM for carbide tooling.
162 SFM with a 0.500-inch tool calculates to 1,238 RPM using RPM = SFM × 12 ÷ (π × diameter).
The material library stores 0.0025 inch per tooth as the 1/4-inch end-mill starting chip load.
Eleven shop calculators in one app - speeds & feeds, tap drill, threading, drill chart, metal weight, surface finish, conversions, plus Pro ShopCAM Lite (canned cycles + threadmill g-code) and Tool Library. Free on the App Store and Google Play.
