Austenitic stainless (304, 316) work-hardens quickly, so the rules are: run slower, never let the tool dwell, and always take a real chip. Rubbing is the fastest way to ruin both the part and the cutter.
Convert SFM to RPM: RPM = (SFM × 3.82) / cutter diameter (in). Then feed rate (IPM) = RPM × chip load × flutes. Do it instantly with the Feeds & Speeds calculators.
Cutting speeds (SFM)
| Operation | HSS (SFM) | Carbide (SFM) |
|---|---|---|
| Milling | 40 – 60 | 150 – 300 |
| Turning | 50 – 70 | 200 – 350 |
| Drilling | 30 – 50 | 100 – 200 |
Recommended chip load
| End mill diameter | Chip load (in/tooth) |
|---|---|
| 1/8 in | 0.0004 – 0.0008 |
| 1/4 in | 0.0008 – 0.0015 |
| 3/8 in | 0.0012 – 0.0020 |
| 1/2 in | 0.0015 – 0.0030 |
| 3/4 in | 0.0020 – 0.0035 |
| 1 in | 0.0025 – 0.0040 |
Starting points for general work. Defer to your tooling manufacturer and adjust for rigidity, coolant, depth of cut, and finish.
Tips
- Never dwell or let the tool spin in place — stainless hardens under a rubbing edge.
- Use sharp TiAlN-coated carbide, a rigid setup, and constant flood coolant.
- Climb mill and commit to a real chip load; a light, timid cut hardens the surface.
- If the work-hardened skin forms, get under it next pass rather than skimming the top.
See the full Feeds and Speeds Chart for every material side by side.