Speeds & Feeds Reference
RPM Formula
RPM = (SFM × 12) / (π × Diameter)
Feed Rate Formula
IPM = RPM × IPT × Flutes
Recommended SFM by Material
| Material | HSS SFM | Carbide SFM |
|---|---|---|
| Low Carbon Steel (1018) | 80–100 | 350–600 |
| Medium Carbon Steel (1045) | 70–90 | 300–500 |
| Alloy Steel (4140) | 60–80 | 250–450 |
| Stainless 304 | 40–60 | 200–350 |
| Stainless 316 | 35–55 | 175–325 |
| Tool Steel (D2) | 30–50 | 150–275 |
| Tool Steel (A2) | 40–60 | 175–300 |
| Tool Steel (O1) | 50–70 | 200–350 |
| Aluminum 6061 | 300–500 | 800–1500 |
| Aluminum 7075 | 250–450 | 700–1200 |
| Brass | 150–300 | 500–800 |
| Bronze | 100–200 | 350–600 |
| Cast Iron (Gray) | 60–80 | 250–450 |
| Cast Iron (Ductile) | 50–70 | 200–400 |
| Copper | 100–200 | 400–700 |
| Titanium 6Al-4V | 25–40 | 100–200 |
| Inconel 718 | 10–20 | 60–120 |
| Plastics (Acetal, Nylon) | 200–400 | 500–1000 |
Recommended IPT by Operation
| Operation | Aluminum IPT | Steel IPT | Stainless IPT |
|---|---|---|---|
| Face Milling | .006–.012 | .004–.008 | .003–.006 |
| End Milling | .004–.008 | .003–.006 | .002–.004 |
| Slotting | .003–.006 | .002–.004 | .001–.003 |
| Drilling | .004–.008 | .003–.006 | .002–.004 |
| Reaming | .004–.010 | .003–.008 | .002–.005 |
| Tapping | 1/TPI | 1/TPI | 1/TPI |
Cutting Speed Formulas
Metric: Vc = (π × D × n) / 1000
Where Vc = cutting speed (m/min), D = diameter (mm), n = RPM