Are All Types of Aluminum Tubing Created Equal for Machining?

You need aluminum tubing¹ for a machined part. But choosing a standard structural type for a high-stress application can lead to catastrophic failure, jeopardizing your project and reputation.

No. The main types are extruded tubes (like 6063 for architecture) and seamless tubes (like 6061 for structure). For high-performance machined parts, a custom-forged hollow bar is a superior category, engineered for metallurgical soundness and strength, not just shape.

I talk to machinists every day who are forced to work with the wrong material. They are given a standard extruded tube and asked to create a high-performance part from it. This is like asking a carpenter to build a fine cabinet out of a shipping pallet. The "type" of material you start with should be defined by its integrity, not just its shape. Standard tubes are for basic structures. Our forged hollow bars are the proper metallurgical starting point for mission-critical machined components. For these parts, internal soundness and predictable performance are the only specifications that matter.

Which aluminum is stronger, 6061 or 6063?

You see that 6063 tubing is often cheaper and more available. This makes it tempting for a structural application, but it lacks the necessary strength, leading to potential bending and failure under load.

6061 aluminum² is significantly stronger than 6063. A 6061-T6 tube has a tensile strength around 310 MPa (45,000 psi), while a 6063-T6 tube is only around 241 MPa (35,000 psi), making 6061 the clear choice for structural parts.

This is one of the most important distinctions to make when sourcing aluminum. Choosing the wrong one can have serious consequences. They may look similar, but their purpose and performance are worlds apart. We always guide our customers to use 6061 for any part that will bear a load.

Application Defines the Alloy

Think of them as two different tools designed for different jobs.

• 6063 Aluminum (The Finisher): This alloy is the master of shapes. It contains less magnesium and silicon, which makes it easier to extrude into complex profiles with a very smooth surface finish. Its primary job is aesthetics and light structural use, like window frames, door frames, and architectural trim. It has good corrosion resistance³ but is not meant for high stress.

• 6061 Aluminum (The Builder): This is the workhorse of structural aluminum. With more magnesium and silicon, it's harder to extrude but offers a much better combination of strength, toughness, and corrosion resistance. It's used for machine bases, structural supports, hydraulic components, and our forged rings and hollow bars. For any machined part that requires reliable strength, 6061 is the minimum standard.

Which aluminum is stronger, 5052 or 6061?

You need a strong but formable material. You see 5052 praised for its formability and 6061 for its strength, leaving you unsure which is right for your complex part.

6061-T6 is significantly stronger than any temper of 5052. However, 5052 has superior formability and fatigue strength, making it the better choice for parts made from sheet metal that require extensive bending and forming.

This question moves us from structural tubes to a different category of aluminum applications. While we specialize in forging, understanding these alloys is key to guiding our trading partners. The choice between 5052 and 6061 is a classic engineering trade-off between strength and ductility.

Strength vs. Workability

You cannot have the best of both worlds with these two alloys. You must choose which property is more critical for the final application.

For any component we would produce, like a large forged ring or disc meant for machining, 6061 is the obvious choice. Its properties are enhanced by heat treatment. 5052 is the star for products made by bending and shaping sheet.

Is aluminum tubing measured ID or OD?

You need to order tubing, but you are not sure which dimension is the industry standard. Specifying the wrong one can result in receiving material that doesn't fit your chucks or fixtures.

*For most commercial aluminum tubing, the Outer Diameter (OD) and the wall thickness are the standard specified measurements. The Inner Diameter (ID) is then calculated from these two values (ID = OD - 2 Wall Thickness).**

This is a point of frequent confusion, but the logic is straightforward for mass-produced tubes. The OD is the critical dimension for clamps, fittings, and structural interfaces, so it is held to a tighter tolerance. The wall thickness determines the tube's strength and weight. The ID is simply what's left over and often has a wider tolerance range.

Why This Doesn't Work for Precision Machining

This standard system is a problem for machinists. For a high-precision part like a bushing or a sleeve, the finished ID is just as critical as the OD.

1. Buying Standard Tube: If you buy a standard tube, you might get an ID that is too big, leaving no material for cleanup, or an ID that is too small, forcing you to waste hours boring out excess material.
2. The SWA Forging Solution: We work backward from your final part. You tell us the finished OD and ID. We then engineer a custom forged hollow bar with the ideal amount of machining stock on both surfaces. You specify the OD and ID you need to start with, not just the OD and wall. This gives you complete control and minimizes waste.

Conclusion

The "type" of tubing you need is one that guarantees internal integrity. For critical machined parts, skip standard tubes and start with a custom-forged hollow bar engineered for performance.