Aluminum Custom Parts Manufacturing
Aluminum alloys are the fastest-machining metals we work with. High cutting speeds, low tool wear, and clean chip formation translate directly to shorter cycle times and lower per-part costs compared to steel or stainless — which is why aluminum is specified whenever the application allows it.
The alloys divide into two broad groups. Non-heat-treatable grades like 2011 are optimized for machinability and run at the highest speeds on screw machines and Swiss lathes. Heat-treatable grades like 6061 and 7075 provide higher strength and corrosion resistance, with 7075-T6 approaching the tensile strength of some mild steels at one-third the weight. We machine all four common grades (2011, 2024, 6061, 7075) across CNC milling, turning, multi-spindle, and Swiss platforms, producing custom aluminum precision machined parts from single prototypes through high-volume production runs.
Tolerances range from ±0.002" to ±0.005" for most work. Tighter tolerances to ±0.001" are achievable on free-machining 2011 and on small-diameter Swiss-turned parts, with attention to thermal expansion — aluminum moves roughly twice as much as steel per degree of temperature change, which means shop temperature and coolant management affect dimensional accuracy on tight-tolerance work.
Aluminum alloys for machining fall along a spectrum. At one end, 2011 is optimized for production speed — it cuts fast and clean but offers the lowest strength and corrosion resistance. At the other end, 7075 provides the highest strength but machines more slowly and costs more. Choosing the right grade means matching the application's structural, environmental, and cost requirements against machinability.
Free-machining aluminum alloy. Contains bismuth and lead for superior machinability, making it ideal for high-volume production. While not as strong as 6061 or 7075, it machines extremely well and can achieve excellent surface finishes. Perfect for parts requiring complex features or tight tolerances.
Material Properties (Scale 1-10)
Material Cost: 7
Machining Cost: 2
Durability: 8
Corrosion Resistance: 9
Temperature Resistance: 7
Strength-To-Weight Ratio: 5
Typical Tolerances: ±0.002" to ±0.005"
Magnetic: No
High-strength aircraft grade aluminum. Offers excellent fatigue resistance and good strength-to-weight ratio. Better machinability than 7075 while providing similar strength levels. Its balanced properties make it suitable for parts requiring both good machinability and high strength.
Material Properties (Scale 1-10)
Material Cost: 7
Machining Cost: 4
Durability: 8
Corrosion Resistance: 5
Temperature Resistance: 6
Strength-To-Weight Ratio: 8
Typical Tolerances: ±0.002" to ±0.005"
Magnetic: No
Most versatile and widely used aluminum alloy. Combines good machinability with excellent corrosion resistance and medium strength. Heat-treatable, weldable, and accepts anodizing well. Its balance of properties and cost-effectiveness makes it the go-to choice for many machined components.
Material Properties (Scale 1-10)
Material Cost: 4
Machining Cost: 3
Durability: 6
Corrosion Resistance: 8
Temperature Resistance: 6
Strength-To-Weight Ratio: 6
Typical Tolerances: ±0.002" to ±0.005"
Magnetic: No
High-strength aerospace grade aluminum. Offers the highest strength of common aluminum alloys, nearly matching some steels. While more expensive and slightly harder to machine than 6061, it provides superior mechanical properties. Ideal for applications requiring maximum strength and excellent fatigue resistance.
Material Properties (Scale 1-10)
Material Cost: 8
Machining Cost: 5
Durability: 9
Corrosion Resistance: 6
Temperature Resistance: 7
Strength-To-Weight Ratio: 9
Typical Tolerances: ±0.002" to ±0.005"
Magnetic: No
Aluminum's excellent thermal conductivity and lightweight properties make it ideal for electronic housings and heat management components. The material's good machinability allows for complex cooling channels and intricate designs, while its natural corrosion resistance ensures long-term reliability. Aluminum's high strength-to-weight ratio enables large housings and enclosures that remain lightweight yet durable, making it particularly valuable in electronic and HVAC applications where heat dissipation is crucial.
Common Components:
• Heat sinks and thermal spreaders
• Electronic enclosures
• Power supply housings
• LED light fixtures and housings
• Control panel enclosures
• Motor housings
• Heat exchanger components
• Cooling blocks
• Server rack components
• Circuit board mounting frames
In precision measurement applications, aluminum provides an optimal balance of light weight and stability. Its excellent machinability enables the production of precise instrument housings and components while maintaining tight tolerances. The material's good strength-to-weight ratio allows for robust instrument designs without excess bulk, while its corrosion resistance ensures long-term reliability in various environments. The ability to anodize aluminum also provides enhanced surface hardness and wear resistance for instrument components.
Common Components:
• Pressure gauge housings
• Sensor mounting blocks
• Calibration equipment frames
• Instrument enclosures
• Test equipment housings
• Mounting brackets and supports
• Precision alignment fixtures
• Gauge bodies
• Probe holders
• Measurement device frames
Aluminum's combination of corrosion resistance and machinability makes it well-suited for fluid control applications. The material can be machined into complex manifolds and flow control components with intricate internal passages. Its good strength-to-weight ratio allows for robust designs that remain lightweight, while its thermal conductivity can help manage fluid temperatures. The ability to achieve excellent surface finishes also makes it suitable for applications requiring specific flow characteristics.
Common Components:
• Hydraulic manifolds
• Valve bodies
• Flow meter housings
• Distribution blocks
• Pump components
• Filter housings
• Coupling bodies
• Flow control bodies
• Pneumatic system components
• Fluid sampling blocks
Aluminum is the most efficient material to machine in our shop. Higher cutting speeds, longer tool life, and faster cycle times make it the lowest-cost option per part in most geometries. That efficiency means we can hold tight tolerances and fine finishes on aluminum without the cost premium those specifications add on harder materials.
The main machining challenges with aluminum are different from steel or stainless. Work hardening isn't a concern — aluminum doesn't harden under the tool the way stainless does. Instead, the issues are thermal expansion, chip evacuation, and surface finish on softer grades. Aluminum expands roughly 13 µin/in/°F (about twice the rate of steel), so temperature control through coolant management and consistent cutting parameters directly affects dimensional accuracy on tight-tolerance work. On 6061 and 7075, long chips can wrap around tooling or pack in bores if chip breakers and coolant pressure aren't set up correctly.
We manufacture custom aluminum precision machined parts across four core processes.
Aluminum milling work ranges from simple bracket-and-housing jobs in 6061 to complex manifold blocks with deep intersecting bores and thin-wall features. Our milling centers (vertical and horizontal, up to 6-axis) run aluminum at high spindle speeds with large material removal rates. Precision milled aluminum parts with thin walls (down to 0.030" in some geometries) require fixture strategies that account for aluminum's tendency to deflect under clamping pressure and spring back after machining — we fixture these parts to support the wall, not fight the material. Six-axis machining reduces setups on complex aluminum housings and enclosures, which matters for two reasons: fewer setups means fewer positional tolerance stack-ups, and fewer part handlings means less chance of marring soft aluminum surfaces.
2011 aluminum is among the best-performing materials on multi-spindle equipment. Its chip-breaking additions produce the short, well-formed chips that multi-spindle operations require, and its machinability allows aggressive cycle times. We process aluminum bars up to 1-5/8" and chucking to 6" diameter. Fittings, connectors, adapter bodies, and threaded components produced in volumes of 10,000+ are the core work on this platform. 6061 runs on multi-spindle as well, though less efficiently. Its longer chips require more careful management and slightly longer cycle times. When volumes are high enough, the per-part cost advantage of multi-spindle still holds.
Precision aluminum turning covers the widest range of part sizes — bar stock up to 4" and chucking to 20" diameter. Shafts, housings, bushings, and cylindrical components across all four grades run on our turning centers. Live tooling handles cross-drilling, flats, and off-axis features in a single setup, which is particularly useful on aluminum where maintaining concentricity after re-fixturing a soft workpiece is harder than on steel. For high-precision aluminum turning (tolerances tighter than ±0.002"), we control tool engagement, cutting speed, and coolant temperature to manage thermal expansion. A part that measures correctly at the spindle can grow measurably by the time it reaches the inspection table if these variables aren't managed.
Small aluminum parts (up to 7/8" diameter, 4" length) with tight tolerances and complex features run on our Swiss lathes. This is where 2011 aluminum performs best — the combination of guide bushing support, free-machining chip formation, and high-speed cutting produces small-diameter precision parts with excellent surface finish and dimensional repeatability. Instrument fittings, electronic connector bodies, miniature threaded adapters, and probe components are typical Swiss-turned aluminum work. The guide bushing eliminates the deflection that small-diameter aluminum parts are prone to during turning, allowing tolerances to ±0.001" on features that would be difficult to hold in a conventional chuck.
Learn more about our machining services and capabilities
Delivering high-quality, consistent aluminum components is a top priority at Spex. Our quality system is built on our ISO 9001:2015 certification, guiding how we work every step of the way. We carefully check parts during production to ensure dimensional accuracy and address the specific needs of machining aluminum alloys effectively — including managing thermal expansion effects that can shift dimensions between machining and inspection if parts aren't allowed to stabilize at room temperature.
We apply these same quality standards whether we're making a single prototype or thousands of parts. You can be confident in the results, as each project comes with full documentation, including material certifications, detailed measurement reports, and First Article Inspection Reports (FAIRs). This paperwork clearly shows how your parts meet your exact specifications.
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Scalable production
Short lead times
Fair prices
ISO-9001 certified
Secondary processes
Range of materials
On-time delivery
75+ years in business
Advanced CNC machining
Rapid prototyping
2011 is the most machinable aluminum alloy available. Its bismuth and lead additions break chips at the cutting edge, producing short segments instead of the long, stringy chips other aluminum grades create. 2011 runs at the highest speeds, causes the least tool wear, and holds tolerances most consistently in high-volume production. The tradeoff is lower strength and corrosion resistance — 2011 is selected for internal components, plated parts, and applications where mechanical loads are light. When the part needs both good machinability and structural strength, 6061 is the general-purpose choice. For maximum strength, 7075 machines well but more slowly.
Strength. 7075-T6 reaches roughly 83 ksi tensile strength — nearly double 6061-T6's 45 ksi. Both weigh the same. 7075 costs more, machines somewhat less efficiently, and has lower corrosion resistance than 6061. It also doesn't anodize to the same cosmetic quality. The decision usually comes down to whether the part's structural load requires 7075's extra strength, or whether 6061's balance of properties (adequate strength, good corrosion resistance, easy anodizing, lower cost) is sufficient.
Yes, and they frequently are. Type II anodizing creates a 5–25 µm oxide layer that improves corrosion resistance and can be dyed in a range of colors. Type III hardcoat anodizing produces a thicker 25–75 µm layer with significantly increased surface hardness and wear resistance. 6061 anodizes well with a consistent, uniform finish. 7075 and 2024 anodize acceptably but may show slight color variation due to their copper content. 2011 does not anodize to cosmetic quality — parts in this grade are typically plated or used unfinished. We coordinate aluminum anodizing through established secondary process partners.
Aluminum expands at roughly 13 µin/in/°F — about twice the rate of steel. On parts with tolerances of ±0.002" or wider, this is a non-issue. On tighter-tolerance work (±0.001" or better), the temperature difference between a machine running at full speed and a climate-controlled inspection room can produce measurable dimensional shifts. We manage this through consistent coolant application, allowing parts to stabilize at room temperature before final inspection, and accounting for thermal growth in our process planning. If a drawing specifies inspection at 68°F (20°C), parts are measured at that temperature.
Some grades are. 7075-T6 provides 83 ksi tensile strength (comparable to some carbon steels) at one-third the weight. 2024-T4 reaches 68 ksi with superior fatigue resistance. These alloys are used in structural brackets, gearbox housings, and load-bearing fixtures where the alternative would be heavier steel. 6061-T6 at 45 ksi covers moderate-strength applications. Aluminum is not suitable when the application requires the hardness, wear resistance, or stiffness that steel provides — aluminum's modulus of elasticity (10 Msi) is roughly one-third of steel's (30 Msi), so it deflects more under the same load even when the tensile strength is comparable.
Provide part drawings or CAD models with the aluminum alloy specified (e.g., 2011, 6061-T6, 7075-T6), required tolerances, order quantity, and any critical features. Include secondary operations if needed: anodizing (specify type and color), plating, powder coating, or painting. If you're not sure which grade fits your application, describe the operating environment, load conditions, and whether the part needs to be anodized, and we can recommend options.
