These speeds suit mild and low-carbon steels such as 1018 and A36. Drop toward the low end for tougher alloy and medium-carbon grades like 4140 and 1045, which run roughly 20–30% slower.
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 | 80 – 110 | 300 – 500 |
| Turning | 90 – 120 | 350 – 600 |
| Drilling | 60 – 90 | 200 – 350 |
Recommended chip load
| End mill diameter | Chip load (in/tooth) |
|---|---|
| 1/8 in | 0.0005 – 0.0010 |
| 1/4 in | 0.0010 – 0.0020 |
| 3/8 in | 0.0015 – 0.0030 |
| 1/2 in | 0.0020 – 0.0040 |
| 3/4 in | 0.0030 – 0.0050 |
| 1 in | 0.0040 – 0.0060 |
Starting points for general work. Defer to your tooling manufacturer and adjust for rigidity, coolant, depth of cut, and finish.
Tips
- TiN or TiAlN coated carbide handles steel well; 4 flutes give a good finish.
- Use flood coolant and a rigid setup to manage heat and keep tolerances.
- Keep the chip load up — rubbing instead of cutting work-hardens the surface and dulls the edge fast.
- For 4140 / 1045, start near the bottom of each range and increase once stable.
See the full Feeds and Speeds Chart for every material side by side.