Feed & Speed Calculator for Brass
Free-machining brass is about as easy as metal gets — the main thing to get right is matching feed to grade so the chip breaks instead of stringing.
Brass starting ranges
| Tool | Cutting speed (SFM) | Chip load, 1/2" 3-flute (in) |
|---|---|---|
| Carbide | 500–1000 | 0.004–0.008 |
| HSS | 150–300 | 0.003–0.006 |
Leaded, free-cutting grades (C360) run toward the top of these ranges; lead-free brass (C260 and similar) is noticeably gummier and should run toward the bottom.
Not all brass cuts the same way
Leaded free-cutting brass (C360) is specifically alloyed to produce short, clean chips and is genuinely one of the easiest materials to machine well — but environmental regulations have pushed lead-free brass grades into wider use, and those cut noticeably gummier, closer to copper's behavior. If a part's chips are stringing instead of breaking, check whether the stock is actually a lead-free grade before assuming the feeds and speeds are wrong.
Zero rake and positive rake tools behave differently here
Free-cutting brass is one of the few materials where a slightly negative or zero-rake tool geometry can actually cut cleaner than an aggressive positive rake, because the leaded chips shear more predictably under those conditions — this is the opposite of what works best in steel or aluminum, and it's worth knowing before assuming a "sharper is always better" tool will give the best finish.
Watch for chip stringing on lead-free grades
If chips are coming off long and stringy instead of breaking into short pieces, that's the clearest sign you're in a gummier lead-free grade — raising chip load (not speed) usually helps the chip break more cleanly, similar to the fix for copper.
Find It on Amazon
Search Amazon directly for tooling, gauges, and shop supplies.