Start with two different ideas.
Surface speed describes how fast the cutting edge moves relative to the material. Feed per tooth describes how far the tool advances for each effective cutting tooth. RPM and table feed connect those two inputs to your cutter.
Select cutting data for the actual tool, material, engagement, and application. The calculator translates that data; it does not choose it for you.
Feed (in/min) = RPM × cutting teeth × feed per tooth
Work an arithmetic example.
Use a 0.500-inch cutting diameter, 400 SFM, three effective teeth, and 0.004 inch per tooth. These are demonstration values, not a recipe for a particular material.
| Step | Calculation | Result |
|---|---|---|
| Spindle speed | 400 × 12 ÷ (π × 0.5) | 3,055.77 RPM |
| Table feed | 3,055.77 × 3 × 0.004 | 36.67 in/min |
| Removal rate | 36.6693 × 0.25 × 0.25 | 2.292 in³/min |
What if the spindle is limited?
Set the spindle limit to 1,000 RPM. The achieved surface speed falls to 130.90 SFM. To maintain 0.004 inch per tooth with three teeth, table feed becomes 12.00 in/min.
One change affects another. A spindle cap changes both achieved surface speed and the feed required to preserve your entered feed per tooth. Review whether the reduced cutting speed is suitable for the tool and material.
Use the number as a starting calculation.
The tool’s application data, machine and holder limits, rigidity, and process verification still govern the operation. The workbench can apply radial chip thinning when you explicitly choose target maximum chip thickness. Keep Programmed feed mode for operation-specific or already compensated data. Changing contact diameter is not modeled. Use effective cutting diameter and effective tooth count for the operation.
Switch to Metric in the calculator to convert the same inputs. Feed is displayed in mm/min and removal rate in cm³/min.
Reproduce this exampleFormula reference: Sandvik Coromant milling formulas and definitions . Explanation and example by Rocket City Machinist.