Engineering quick reference
Speeds, Feeds & Chip Load Chart
Recommended chip load (feed per tooth) by end-mill diameter across material groups, plus turning/milling SFM by material.
RPM = (SFM × 3.82) / D (3.82 ≈ 12/π)
IPM = RPM × flutes × IPT
Chip load is the chip thickness each flute takes — too thin rubs and work-hardens, too thick snaps tools. Radial chip thinning at stepover ae < D/2: RCTF = 1 / √(1 − (1 − 2·ae/D)²) ≈ 1.15× @ 25% · 1.4× @ 15% · 1.67× @ 10%.
Recommended chip load (in/tooth) by end-mill diameter — solid carbide
| Material group | Chip load, IPT (in/tooth) — by end-mill Ø | ||||||
|---|---|---|---|---|---|---|---|
| 1/8″ | 3/16″ | 1/4″ | 3/8″ | 1/2″ | 3/4″ | 1″ | |
Aluminum (6061 / 7075) Free-cutting; high MRR. Sharp uncoated/polished or ZrN flutes, generous chip room. | 0.001–0.002 | 0.0015–0.0025 | 0.002–0.004 | 0.003–0.005 | 0.004–0.007 | 0.005–0.009 | 0.006–0.011 |
Mild & low-alloy steel 1018, 1045, 4140/4340 (prehard ≤ ~32 HRC). Coated carbide; flood or MQL. | 0.0005–0.001 | 0.001–0.0017 | 0.0015–0.0025 | 0.002–0.0035 | 0.0025–0.004 | 0.0035–0.0055 | 0.004–0.007 |
Stainless & PH steel 304/316L, 17-4PH, 15-5PH. Keep the tool cutting — too light a chip work-hardens the surface. | 0.0004–0.0009 | 0.0008–0.0014 | 0.0012–0.002 | 0.0018–0.003 | 0.002–0.0035 | 0.003–0.0045 | 0.0035–0.0055 |
Titanium (Ti-6Al-4V) Low thermal conductivity; high cutting pressure. High-pressure coolant, avoid dwell. | 0.0003–0.0007 | 0.0005–0.001 | 0.0007–0.0015 | 0.001–0.002 | 0.0014–0.0025 | 0.002–0.0035 | 0.0025–0.004 |
Nickel superalloy (Inconel) Inconel 718, 625. Severe work-hardening; rigid setup, positive geometry, never rub. | 0.0003–0.0006 | 0.0005–0.0009 | 0.0007–0.0013 | 0.001–0.0018 | 0.0012–0.0022 | 0.0016–0.003 | 0.002–0.0035 |
Brass / Bronze C360 brass, C932 bronze. Free-machining; sharp tools, watch for grabby zero/negative rake. | 0.001–0.002 | 0.0015–0.0025 | 0.002–0.0035 | 0.0025–0.0045 | 0.003–0.006 | 0.004–0.0075 | 0.005–0.009 |
Plastics (Delrin / PEEK / Ultem) Sharp single/two-flute or O-flute; clear chips fast to avoid melting and re-cutting. | 0.001–0.003 | 0.002–0.004 | 0.003–0.006 | 0.004–0.008 | 0.005–0.01 | 0.006–0.012 | 0.007–0.014 |
Each cell = low–high IPT range.Feed per tooth (in) for square end mills at ~30–50% radial engagement. Use the low end for small/long-reach tools and finishing; the high end for rigid setups and roughing. Apply RCTF (above) at light stepover before computing IPM. See the fullchip load chart.
Cutting speed (SFM) by alloy — solid-carbide turning & milling
| Alloy | Family | Carbide SFM | Mach. | |
|---|---|---|---|---|
| Rough | Finish | |||
| Metals | ||||
| 2024-T3 | Aerospace aluminum (Cu-Mg) | 500–1200 | 700–1500 | 80 |
| 7075-T6 | Aerospace aluminum (Zn-Mg-Cu) | 800–1500 | 1200–2000 | 70 |
| 6061-T6 | Aluminum (Mg-Si) | 600–1500 | 800–2000 | 90 |
| 304 Stainless | Austenitic stainless | 300–400 | 400–500 | 50 |
| 316L Stainless | Austenitic stainless | 300–450 | 400–550 | 45 |
| MIC-6 | Cast aluminum tooling plate (Al-Si) | 600–1500 | 800–2000 | 90 |
| A2 Tool Steel | Cold-work tool steel | 200–300 | 300–400 | 70 |
| D2 Tool Steel | Cold-work tool steel | 330–490 | 490–655 | 50 |
| BeCu C172 | Cu-Be alloy (precipitation hardening) | 300–500 | 400–600 | 40 |
| Brass C360 | Free-machining brass (Cu-Zn-Pb) | 500–1000 | 600–1200 | 100 |
| H13 Tool Steel | Hot-work tool steel | 200–300 | 300–400 | 75 |
| C932 Bronze | Leaded tin bronze | 300–500 | 500–700 | 70 |
| 4130 Chromoly | Low-alloy steel | 300–400 | 400–500 | 70 |
| 4140 Steel | Low-alloy steel | 150–250 | 250–400 | 65 |
| Magnesium AZ31 | Mg-Al-Zn alloy | 1500–3000 | 2500–4000 | 100 |
| Inconel 718 | Ni-Cr-Fe-Nb superalloy | 30–60 | 50–100 | 12 |
| Hastelloy C-276 | Nickel superalloy (corrosion grade) | ~90 | 95–110 | 18 |
| Monel 400 | Nickel-copper alloy | 100–150 | 150–225 | 35 |
| 17-4PH Stainless | Precipitation-hardening stainless | 150–250 | 200–300 | 45 |
| 4340 Steel | Premium low-alloy steel | 100–200 | 200–350 | 50 |
| C110 Copper | Pure copper (>99.9%) | 400–700 | 600–900 | 20 |
| 17-7PH Stainless | Semi-austenitic PH stainless | 150–225 | 225–300 | 35 |
| Ti-6Al-4V | α-β Titanium | 150–200 | 200–260 | 22 |
| Plastics | ||||
| Delrin / POM | Engineering thermoplastic | 300–600 | 400–800 | 80 |
| Ultem (PEI) | Engineering thermoplastic (high-T amorphous) | 200–500 | 300–700 | 70 |
| PEEK | High-performance semi-crystalline thermoplastic | 200–400 | 300–600 | 65 |
SFM ranges are typical solid-carbide values for the listed condition; coatings and rigidity shift the working value. Mach. = relative machinability index on family-specific scales (steels vs AISI B1112 = 100; copper alloys vs C360 = 100; tool steels vs W1 = 100) — compare within a family only. Convert to spindle speed with RPM = (12 × SFM) / (π × D). For composition, specs, and per-alloy machining notes, see the fullmaterial datasheets.
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