Starting surface speeds with HSS: 6061 aluminum 250 SFM, 360 brass 200, 12L14 steel 150, 1018 steel 100, 1045 steel 80, 304 stainless 50, titanium 30. Carbide runs about three times faster. Convert with RPM = 3.82 x SFM / diameter.
These are conservative starting points sized for hobby lathes and benchtop mills, which flex more than the industrial machines most handbook tables assume. Start here, then raise the speed while the chips stay clean and the tool stays cool. Each material links to its own speeds and feeds pages.
Tools that go with this chart
Surface speed by material
| Material | HSS SFM | Carbide SFM | HSS drill SFM | Machinability |
|---|---|---|---|---|
| 6061-T6 aluminum | 250 | 800 | 200 | Excellent |
| 7075-T6 aluminum | 250 | 800 | 200 | Excellent |
| 360 free-machining brass | 200 | 500 | 150 | Best of any common metal (the 100% reference) |
| 932 bearing bronze | 90 | 300 | 80 | Good |
| 110 copper | 100 | 350 | 90 | Poor (gummy) |
| 12L14 leaded steel | 150 | 500 | 110 | Excellent (about 170% of 1212) |
| 1018 cold rolled steel | 100 | 350 | 80 | Fair (about 70%) |
| 1045 medium carbon steel | 80 | 300 | 70 | Fair (about 57%) |
| 4140 alloy steel (annealed) | 60 | 250 | 50 | Fair (about 65% annealed) |
| A36 hot rolled steel | 90 | 325 | 75 | Fair |
| 303 stainless steel | 70 | 250 | 50 | Fair (about 78% of free steel) |
| 304 stainless steel | 50 | 200 | 40 | Poor (about 45%) |
| 316 stainless steel | 45 | 180 | 35 | Poor (about 36%) |
| Gray cast iron (class 30) | 70 | 250 | 60 | Good |
| O1 tool steel (annealed) | 50 | 200 | 40 | Fair (about 45%) |
| Titanium 6Al-4V | 30 | 120 | 25 | Poor (about 22%) |
| Delrin (acetal) | 300 | 600 | 200 | Excellent |
HSS spindle RPM at common diameters
| Material | 1/4" | 1/2" | 1" | 2" |
|---|---|---|---|---|
| 6061-T6 aluminum | 3,820 | 1,910 | 955 | 477 |
| 7075-T6 aluminum | 3,820 | 1,910 | 955 | 477 |
| 360 free-machining brass | 3,056 | 1,528 | 764 | 382 |
| 932 bearing bronze | 1,375 | 688 | 344 | 172 |
| 110 copper | 1,528 | 764 | 382 | 191 |
| 12L14 leaded steel | 2,292 | 1,146 | 573 | 286 |
| 1018 cold rolled steel | 1,528 | 764 | 382 | 191 |
| 1045 medium carbon steel | 1,222 | 611 | 306 | 153 |
| 4140 alloy steel (annealed) | 917 | 458 | 229 | 115 |
| A36 hot rolled steel | 1,375 | 688 | 344 | 172 |
| 303 stainless steel | 1,070 | 535 | 267 | 134 |
| 304 stainless steel | 764 | 382 | 191 | 95 |
| 316 stainless steel | 688 | 344 | 172 | 86 |
| Gray cast iron (class 30) | 1,070 | 535 | 267 | 134 |
| O1 tool steel (annealed) | 764 | 382 | 191 | 95 |
| Titanium 6Al-4V | 458 | 229 | 115 | 57 |
| Delrin (acetal) | 4,584 | 2,292 | 1,146 | 573 |
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Frequently asked questions
Why are these speeds lower than Machinery's Handbook?
Handbook tables assume rigid, powerful industrial machines and are often quoted for a given tool life under production conditions. A 7x mini lathe or a benchtop mill has a fraction of the rigidity and power, so chatter and stalling set in first. These starting points leave headroom; raise them when the setup allows.
Should I run carbide at carbide speeds on a mini lathe?
Only on larger diameters. Carbide works best at high surface speed, and a 2,500 RPM spindle cannot give a small workpiece enough of it. On small diameters a sharp HSS tool often leaves a better finish on a hobby lathe than carbide running too slowly.
Keep going
Figures are from published standards and handbook values, reproduced for convenience. Check critical dimensions against the standard or your tooling manufacturer.