303 Stainless Steel Speeds and Feeds (Milling, Drilling, Turning)
Carbide end mills in 303 Stainless Steel: 250–350 SFM. Also called SS303, UNS S30300. Chart row used: “Stainless Steel – Soft” (Annealed (soft stainless row)).
Starting point: carbide end mills
RPM and IPM use the low end of the published range (250 SFM and the lowest chip load for each diameter range). RPM = SFM × 12 ÷ (π × D); IPM = RPM × flutes × chip load.
| Diameter | Chip load (in/tooth) | RPM | IPM · 2 flute | IPM · 3 flute |
|---|---|---|---|---|
| 1/8" | .0005 | 7,639 | 7.6 | 11.5 |
| 1/4" | .0006 | 3,820 | 4.6 | 6.9 |
| 3/8" | .0008 | 2,546 | 4.1 | 6.1 |
| 1/2" | .0010 | 1,910 | 3.8 | 5.7 |
| 3/4" | .0018 | 1,273 | 4.6 | 6.9 |
| 1" | .0025 | 955 | 4.8 | 7.2 |
| Diameter | Chip load (in/tooth) | RPM | IPM · 2 flute | IPM · 3 flute |
|---|---|---|---|---|
| 3 mm | .0005 | 8,085 | 8.1 | 12.1 |
| 6 mm | .0006 | 4,043 | 4.9 | 7.3 |
| 10 mm | .0010 | 2,426 | 4.9 | 7.3 |
| 12 mm | .0010 | 2,021 | 4.0 | 6.1 |
| 16 mm | .0018 | 1,516 | 5.5 | 8.2 |
| 20 mm | .0025 | 1,213 | 6.1 | 9.1 |
Full published chip-load ranges
- 1/32-1/8": .0005–.0008"
- 1/8-1/4": .0006–.0010"
- 1/4-3/8": .0008–.0015"
- 3/8-1/2": .0010–.0020"
- 1/2-3/4": .0018–.0040"
- 3/4-1": .0025–.0055"
Calculator — prefilled for 303 Stainless Steel
Material library
Tool & coating guidance
Grade, edge geometry and coating determine usable cutting data. Sharp polished edges can suit nonferrous work; substrate and geometry still govern. No coating speed multiplier is inferred.
Tool & cut parameters
Target parameters
Spindle RPM
1,910
Feed Rate (IPM)
7.6
Max chip hex
0.0009"
Chip thinning & cutter body
Fixed-angle peripheral estimate: hex = fz × radial factor × sin(KAPR). No radial correction at ≥50% engagement. Not a centered face-milling or ball-nose model. Sandvik geometry reference
Insert styles, guidelines & formulas
RPM = (SFM × 12) / (π × D) | Feed = RPM × programmed fz × effective zc
Milling Guidelines
- Start at 70% of max SFM, increase gradually
- Chip load too low → rubbing & heat buildup
- Use climb milling when machine rigidity allows
- Radial engagement >50% → reduce feed per tooth
- Round inserts: best for ramp-in and 3D surfaces
Drilling and turning
The source chart covers carbide end mills only, so we don't list drilling or turning numbers for 303 Stainless Steel. Enter your drill or insert maker's cutting data in the drilling calculator or turning calculator.
Machinist tips
- Chip thinning
- At light radial engagement (under half the cutter diameter) the real chip is thinner than the feed per tooth. Raise the feed to keep the chip at the chart value, or the tool rubs and wears.
- Climb vs conventional
- On a rigid CNC, climb mill so each tooth starts thick and exits thin. Use conventional milling on machines with backlash or on hard scale skins.
- Don't let it rub
- Stainless work-hardens. Keep the tool cutting at a steady feed, avoid dwelling, and use flood coolant.
Common questions
- What SFM should I use for 303 Stainless Steel?
- Lakeshore Carbide – General Purpose End Mill Speeds & Feeds lists 250–350 SFM for carbide end mills in the "Stainless Steel – Soft" row. Start at the low end and adjust for your machine.
- What chip load for a 1/2" end mill in 303 Stainless Steel?
- The published range for 3/8–1/2" carbide end mills is .0010–.0020" per tooth. At 250 SFM a 3-flute 1/2" end mill runs about 1910 RPM and 5.7 IPM.
- Are these values for HSS tools, drilling or turning?
- No. The source chart covers carbide end mills only. Use your drill or insert maker's data for drilling and turning.
Sources
- Lakeshore Carbide – General Purpose End Mill Speeds & Feeds — “Stainless Steel – Soft” row (SFM and chip load per tooth).
- Lakeshore Carbide speeds and feeds charts
Starting values only. Adjust for rigidity, tool manufacturer data and machine.
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