6061 (usually 6061-T6) is the workhorse general-purpose aluminum: light, corrosion resistant, weldable, and one of the easiest metals to machine. It cuts fast and clean, so the main concerns are clearing chips and avoiding built-up edge, not raw cutting force.
Key properties
| Property | Typical value |
|---|---|
| Density | 0.098 lb/in³ (2.70 g/cm³) |
| Hardness | ~95 HB (Brinell) |
| Tensile strength (T6) | ~45,000 psi (310 MPa) |
| Machinability | Excellent |
| Composition | Al with ~1% Mg, ~0.6% Si |
Cutting speeds
| Operation | HSS (SFM) | Carbide (SFM) |
|---|---|---|
| Milling | 250 – 300 | 600 – 1200 |
| Turning | 300 – 400 | 500 – 1000 |
| Drilling | 200 – 300 | 400 – 600 |
Convert to RPM: RPM = (SFM × 3.82) / cutter diameter. Use the Feeds & Speeds calculators.
Tooling and setup
- Tools: 2–3 flute, uncoated polished or ZrN carbide, high helix (35–45°).
- Coolant: flood or mist to flush chips and stop built-up edge; air blast works for shallow cuts.
- Tapping: form taps work well in 6061; use plenty of lubricant.
- Watch for: chips welding to the edge — if the finish smears, raise RPM or add coolant.
See Cutting Speeds for Aluminum and the full Feeds and Speeds Chart.