CNC machining 7075 aluminum is the answer when a part needs strength close to mild steel at roughly one third of the weight. Wexmar machines 7075-T6 and 7075-T7351 bar and plate for structural fittings, fixture components, defense hardware and high-load brackets. The alloy is zinc-based, heat treated to high strength, and cuts cleanly, but it carries tradeoffs in corrosion behavior and weldability that belong in the design conversation before the first chip is made.
7075 Aluminum Machinability
7075-T6 has an approximate machinability rating of about 170 on the scale where AISI 1212 steel equals 100. That puts it just behind 6061, and in several ways it is easier to run. The harder temper breaks chips into short curls instead of long strings, holds sharp edges and threads without smearing, and produces a brighter finish. Tool wear is slightly higher than in 6061 because of the hardness, so we track insert life more closely on long runs.
Tolerances and Finish
Because the material resists deflection and tearing, 7075 is a good choice for tight features. Typical production tolerances are plus or minus 0.001 in. on turned diameters and bores, with plus or minus 0.0005 in. achievable on short, well-supported features. Typical finishes run 32 Ra on milled faces and 16 to 32 Ra on turned surfaces. These are typical figures rather than guarantees, and final capability depends on wall thickness, length and stock condition. Inspection on our CMMs is covered on the inspection and quality page.
Shop Notes: Stress, Distortion and Tooling
- Residual stress in thick plate. Quenched 7075 plate holds significant internal stress. For deep pockets we specify T7351 or T651 stress-relieved stock, rough with stock left on, and release clamps before finishing.
- Temper selection. 7075-T6 is susceptible to stress corrosion cracking in the short transverse direction. T73 and T7351 tempers trade a little strength for much better resistance, and we flag this when a drawing shows thick sections in sustained tension.
- Tool geometry. Polished, high-positive carbide with large flutes and flood or through-spindle coolant keeps chips moving. Climb milling and constant chip load help with finish.
- No welding. 7075 is generally treated as non-weldable, so assemblies that would be welded in 6061 need to be designed as one-piece machined parts or bolted joints.
- Burrs. Burrs are smaller and crisper than in 6061, but sharp edges still get a controlled break per the drawing.
Heat Treat and Finish Options
All heat treat and coatings are coordinated through qualified outside processors:
- Type II anodize (color tends to run slightly warmer or yellow compared with 6061)
- Type III hardcoat anodize for wear and abrasion
- Chemical film conversion coating for corrosion protection and grounding
- Over-aging to T73 or re-heat treatment where a drawing calls for it
- Primer and paint systems for exposed structural hardware
Common 7075 Parts and Processes
- Structural fittings, clevises and brackets
- Fixture plates, locators and tooling components
- High-load shafts, spacers and actuator parts
- Gearbox housings and drive components for light assemblies
- Defense and aerospace build-to-print hardware
Precision 7075 turned parts run on the Mazak and Doosan lathes, while prismatic fittings and plates go to the Mazak horizontal machining centers with 4-axis indexing. Small pins and fasteners under 32 mm diameter are candidates for our Maier Swiss machining cells, which run lights-out on repeat work.
Cost Index: 7075 Compared
| Material | Approx. machinability (1212 = 100) | Cost index vs 6061 | Notes |
|---|---|---|---|
| 6061-T6 aluminum | ~180 | 1.0 | Baseline; weldable, lower strength |
| 7075-T6 aluminum | ~170 | 1.3 | High strength; watch stress corrosion |
| 2024-T351 aluminum | ~170 | 1.4 | Fatigue-critical parts |
| 5052-H32 aluminum | ~120 | 1.1 | Lower strength, corrosion resistant |
| 303 stainless | ~78 | 1.8 | Heavier, more corrosion resistant |
| 4140 steel, prehard 28-32 HRC | ~50 | 1.6 | Higher strength, much heavier |
| Ti-6Al-4V titanium | ~22 | 5.0 | Strength-to-weight step up |
These numbers are typical and illustrative for a comparable part; real quotes depend on geometry, quantity, tolerances and mill pricing.
Applications and Industries
Most 7075 aluminum machining at Wexmar serves aerospace hardware, defense and government build-to-print work, instrumentation frames, and industrial tooling where stiffness and light weight both matter. Our government and defense machining page covers DFARS specialty-metals sourcing, material certs and AS9102-format first article reports. If a part does not need the extra strength, 6061 aluminum usually lowers cost and simplifies finishing.
Getting a quote
Send your 7075 part to our shop in Canastota: upload a drawing for an instant estimate, or call (315) 400-2654 during shop hours. A human estimator confirms every quote and will note temper, stock form and finish questions before the order is placed.