RPM for 2" Brass — Cutting Speed
When machining Brass with a 2-inch diameter tool, the recommended spindle speed range is 573–955 RPM, calculated from a surface speed of 300–500 SFM for carbide tooling. Selecting the correct RPM ensures optimal tool life and surface finish quality. Use this reference alongside your feeds and speeds calculator to set up new operations with confidence.
Recommended Cutting Parameters
| Material | Brass |
| Tool Diameter | 2" |
| Recommended SFM Range | 300–500 SFM |
| Recommended RPM Range | 573–955 RPM |
Why These Parameters Matter
Running below the minimum SFM causes built-up edge (BUE) and poor surface finish on Brass; exceeding the maximum accelerates tool wear and risks thermal damage to the workpiece and coating. Staying within the 300–500 SFM range for a 2-inch tool balances productivity with tool life. These values assume sharp carbide tooling in good condition. Dull tools, poor fixturing, or interrupted cuts may require reducing speed by 20–30% from the recommended range. Depth of cut and radial engagement also influence optimal SFM — lighter finishing passes can tolerate the upper end of the range while full-width roughing passes benefit from the lower end.
Compare Materials — 2" Diameter
| Material | RPM (min) | RPM (max) |
|---|---|---|
| Aluminum | 1146 | 1910 |
| Mild Steel | 286 | 477 |
| Hardened Steel | 134 | 229 |
| Stainless Steel | 191 | 344 |
| Titanium | 153 | 306 |
| Cast Iron | 382 | 764 |
| Brass (current) | 573 | 955 |
| Plastic | 764 | 1528 |
Machining Tips for This Combination
Brass (C360 free-cutting, C385 architectural, C46400 naval) loves sharp positive-rake carbide and runs at very high SFM — often 800–1500. Counter-intuitively, switch the cutting-edge rake from positive to zero or slightly negative when turning brass on a lathe to prevent the tool from grabbing and pulling itself into the work, which can snap small bars. Use dry cutting or mist; flood coolant is rarely necessary and can leave water spots on architectural finishes. Chips are tiny and brittle — easy to evacuate but rough on bare skin.
Large-diameter tools (above 1 inch) turn the limiting factor from surface speed into spindle torque and rigidity. Step down axial depth before chasing higher feed rates, because the tool can easily demand more horsepower than the spindle delivers. Indexable insert tooling becomes economically attractive at this size — replacing a single damaged insert is far cheaper than re-grinding a 1.5 inch solid endmill. Run lower RPM with higher chip load per flute (0.005–0.010 inch per tooth on standard steel) to keep cutting forces inside the machine's capability.
Machining Tips
Use sharp, coated carbide tooling rated for Brass. Apply appropriate coolant: flood coolant for steel and stainless, air blast or MQL for aluminum to prevent chip re-cutting. Verify spindle runout (< 0.0002") before production runs. Reduce feed per tooth by 20–30% for the first pass when breaking surface scale on hot-rolled stock. Always consult your tooling manufacturer's recommended parameters as a primary reference and use these values as a cross-check. Monitor chip color and size during the first cut — blue chips or dust-like chips indicate the speed or feed needs adjustment.