RPM = SFM × 3.82 ÷ diameter. Feed (IPM) = RPM × flutes × chip load.

Numbers come from HTC's Performance Carbide chart (catalog p. 190, under 32 HRc), the same chart as our Speeds & Feeds page. SFM starts at the low end of HTC's range; raise it as your setup allows.

Slot and Finish lower the chip load by 25% and 50%. That's a common shop rule of thumb, not part of HTC's chart.

These are starting points. Adjust for rigidity, stickout, workholding, coolant and depth of cut. Over 32 HRc? Call us.