Engineering · Machining guide
How to machine 2024 aluminum.
2024 is the classic aircraft fuselage and wing-skin alloy — outstanding fatigue resistance from copper alloying. Machining is similar to other 2xxx-series aluminum but the copper content brings two complications: the alloy doesn’t weld well, and uncoated machined surfaces corrode quickly. Most production parts are alclad, anodized, or coated for corrosion protection.
01 · Why 2024 differs from 6061/7075
Copper alloying changes everything.
2024 contains 4.4% copper as its primary alloying element, where 6061 uses magnesium-silicon and 7075 uses zinc-magnesium-copper. The copper gives 2024 its outstanding fatigue resistance — the property that makes it the go-to for aircraft skin, wing spars, and fuselage panels that see millions of pressurization cycles in service.
The trade-offs are weldability (poor — the copper precipitates create cracking) and corrosion (worse than 6061 because the copper-rich grains create galvanic micro-cells). Most production 2024 ships as alclad — pure aluminum cladding bonded to both faces — for corrosion protection. Machining usually breaches the cladding, so finished parts get anodized or primer-coated.
02 · Cutting parameters
Numbers that work.
| Operation | Tool | SFM | IPT / IPR |
|---|---|---|---|
| Roughing turn | Uncoated carbide | 900–1700 | 0.010–0.022 IPR |
| Finishing turn | Uncoated carbide | 1300–2200 | 0.005–0.012 IPR |
| Finishing turn | PCD | 2700–4500 | 0.005–0.010 IPR |
| End mill (rough) | Solid carbide 3FL | 750–1300 | 0.005–0.010 IPT |
| End mill (finish) | Solid carbide 3FL | 1100–1800 | 0.003–0.007 IPT |
| Drilling | Solid carbide | 270–450 | 0.005–0.013 IPR |
| Tapping | Spiral-flute HSS | 45–90 | — |
IPT (chip-load) values assume roughly ½–1″ end mills; scale down for smaller tools — see the chip-load chart.
03 · Practical notes
Anodize compatibility is the one wrinkle.
- Tooling: same as 6061/7075 — uncoated polished carbide with sharp positive rake, 3-flute end mills, PCD for high-volume.
- Coolant: water-soluble flood. Standard aluminum-class coolant.
- Anodize struggles: the copper inclusions disrupt the oxide layer in standard sulfuric anodize (Type II). Either mask copper-rich regions, accept slightly poorer cosmetic finish, or specify Type I (chromic acid anodize) which handles copper-bearing alloys better.
- Alclad consideration: 2024 sheet often arrives with pure-aluminum cladding bonded to both faces. Machining surfaces that breach the cladding loses corrosion protection on those features — plan finishing accordingly.
- Stress-corrosion concerns: 2024-T3 in moist environments can experience SCC at high stress. For high-stress sustained-load applications, T8 (artificially aged) or T62 conditions are more SCC-resistant.
- Common AMS: 4037 (sheet/plate). For broader aluminum comparison, see 6061 vs 7075 vs 2024 comparison.
Keep exploring
Related tools & references
Mechanical properties, UNS, AMS specs, and machinability at a glance.
Convert these SFM and IPT figures into spindle RPM and feed rate.
Recommended chip load by tool diameter for aluminum.
2024 aluminum density for part weight and stock estimates.
How 2024-T3 compares to other structural aerospace aluminums.
Need 2024-T3 aluminum parts machined?
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