Speeds and Feeds

Pick your material, tool diameter and number of flutes to get a starting RPM and feed rate for solid carbide end mills. Numbers come from HTC's published Performance Carbide chart for materials under 32 HRc.

Material

Tool diameter

Flutes

Speed (SFM)

SFM range-

Chip load / tooth-

Spindle speed-

Feed rate-

RPM = SFM × 3.82 ÷ diameter. Feed (IPM) = RPM × flutes × chip load. SFM starts at the low end of HTC's range; raise it as your setup allows. If the RPM is more than your spindle can do, run your max RPM and work the feed out from that.

These are starting points. Adjust for machine rigidity, tool stickout, workholding, coolant and depth of cut. Start at the low end, listen to the cut, and work up. HTC: "These are base-line recommendations. Adjust feeds and speeds according to individual circumstances."

Chip load per tooth (inches) by diameter

Material	SFM	1/8"	3/16"	1/4"	3/8"	1/2"	5/8"	3/4"	1"

Source: HTC Tool-Cutter Manufacturing catalog, p. 190, "Performance Carbide Feeds & Speeds, Recommendations for Surface Feet per Minute & Chip Thickness per Tooth, UNDER 32 HRc." For hardened material over 32 HRc, HTC publishes a separate chart (catalog p. 189). Call us and we'll help.

Need more detail?

For slotting vs. side milling, chip thinning, HSM and drilling or tapping, we recommend FSWizard, a machinist calculator app for phone and web.

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