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SFM Reference

Surface Feet per Minute Chart

Use SFM as the surface-speed starting point before calculating RPM from cutter or workpiece diameter.

Direct answer: surface feet per minute is the cutter-edge speed. Choose an SFM range from the material chart, then convert it to RPM with RPM = (SFM x 3.82) / diameter.

Use this as a compact SFM chart when you need a starting cutter-edge speed; use the fuller cutting-speed reference when machinability, Vc, and Kc also matter.

SFM, RPM, and MRR Decision Path

Follow this path from material speed lookup to spindle-speed conversion, formula review, live MRR calculation, and optimization guidance.

1. Material speed chartChoose material SFM or Vc ranges before any diameter, feed, or MRR calculation.Use first when the question is cutting speed by material, SFM chart, Vc table, or machinability range.2. SFM/RPM conversionConvert SFM, Vc, RPM, and diameter after the material speed assumption is known.Use when the user needs a live spindle-speed number, not a material-speed recommendation.3. Formula auditExplain how SFM, RPM, chip load, feed rate, MRR, power, and cut time connect.Use when the equation chain and worked examples need review before trusting calculator output.4. MRR calculatorCalculate milling-style removal rate, cut time, and planning-level power from feed and engagement.Use only after RPM, chip load, feed rate, axial depth, and radial engagement are known.5. Optimization methodDiagnose whether spindle power, engagement, chip evacuation, rigidity, or chatter limits MRR.Use when the live MRR number exists but the shop needs a defensible improvement path.

SFM lookup

Surface Feet per Minute Starting Chart

Starting SFM ranges by material and tool type before converting cutter or workpiece diameter into RPM.

Source: Compiled as conservative shop-floor starting ranges from site calculator assumptions and standard SFM/RPM validation practice.Updated: 2026-06-24
MaterialHSS startCarbide startValidation note
Aluminum 6061/7075600 - 1,200 SFM1,500 - 4,000 SFMWatch chip welding and use polished geometry.
Low-carbon steel80 - 160 SFM400 - 900 SFMAdjust downward for poor rigidity or interrupted cuts.
Alloy steel 414060 - 130 SFM250 - 600 SFMHardness and coating drive the final window.
Stainless 304/31650 - 100 SFM180 - 450 SFMKeep feed positive to avoid work hardening.
Titanium Ti-6Al-4V30 - 70 SFM120 - 250 SFMPrioritize coolant, engagement, and heat control.
Cast iron80 - 180 SFM400 - 900 SFMAbrasiveness and dust control matter more than coolant.

Download / export next steps

SFM to RPM guideConvert selected surface speed into spindle RPM by diameter.RPM calculatorCalculate RPM, SFM, or diameter from the other two values.Cutting-speed referenceUse the fuller Vc and material-speed reference when more context is needed.

How to Use the Chart

  1. Pick the material family and tool type.
  2. Start near the conservative side if rigidity, coolant, or chip evacuation is uncertain.
  3. Convert SFM into RPM by diameter.
  4. Validate chip shape, tool wear, finish, and spindle load before production release.

Conversion Handoff

Use this table for SFM range selection, then use the SFM to RPM guide or RPM calculator to convert by diameter.