If you’re coming from the world of sheet metal fabrication, you’ve likely worked with Aluminum 5052-H32. It’s a fantastic material for bending, welding, and forming. But when it comes to precision machining, it’s not the right choice. For CNC milled or turned parts, Aluminum 6061-T6 is almost always the preferred alloy. In this post we’ll explain why 6061-T6 is the right call for CNC work.
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Why Are 5052 and 6061 Compared?
Aluminum 5052-H32 and 6061-T6 are two of the most commonly used aluminum alloys in manufacturing. Both are lightweight, corrosion-resistant, and widely available, but their mechanical and machining properties differ significantly. 5052 is ideal for sheet metal applications, especially when the part needs to be formed or welded. In contrast, 6061 is the go-to for CNC machining services, thanks to its excellent strength, surface finish, and dimensional stability.
To make the differences clear, here’s a side-by-side comparison:
| Property | 5052-H32 | 6061-T6 |
| Strength | Moderate | Higher |
| Corrosion Resistance | Excellent (especially marine) | Good (suitable for most uses) |
| Machinability | Fair (gummy, poor chip control) | Good (preferred for CNC work) |
| Weldability | Excellent | Good |
| Formability | Excellent | Fair to Good |
| Cost | Slightly higher | Slightly lower |
5052-H32: Excellent for Forming, Not Machining
From a machining standpoint, 5052 is a challenge. Its relatively soft and ductile nature leads to stringy chips that don’t break cleanly. This causes built-up edge (BUE), a phenomenon where material welds itself to the cutting tool, resulting in poor finishes, dimensional inaccuracies, and rapid tool wear. For this reason, we strongly discourage using 5052 for CNC-milled or turned parts. Cycle times are longer, surface finishes are worse, and tool maintenance increases, all of which drive up costs unnecessarily.
6061-T6: The Machining Standard
Aluminum 6061-T6 is one of the most versatile and widely used alloys in CNC machining. It offers an excellent strength-to-weight ratio, good corrosion resistance, and outstanding machinability. That makes it perfect for parts like brackets, mounting plates, structural components, enclosures, and housings.
6061 produces clean chips, holds tight tolerances, and responds well to a range of post-processing techniques, including anodizing. Whether you’re working in aerospace, automation, robotics, or consumer products, this material allows for efficient machining with high accuracy and repeatability. It’s no surprise that machine shop professionals nearly always recommend 6061 when tight tolerances and fine finishes matter.
Design and Tolerance Considerations
When it comes to precision machining, tolerances matter in choosing your material. 6061 holds tight tolerances for drilled holes, milled pockets, and tapped features far more easily than 5052. It also supports better surface finishes right off the machine, reducing the need for extensive post-processing.
For example:
- Hole locations in 6061 can consistently achieve ±0.002″.
- Flatness and parallelism can be held to a few thousandths of an inch.
- Threads, counterbores, and pockets come out clean without secondary operations.
None of this is guaranteed with 5052. Even with expert tooling and techniques, the material simply doesn’t cut cleanly enough to maintain consistency. That’s why, at Approved Machining, we always steer machining projects toward 6061 when aluminum is specified.
Your Trusted Partners for CNC Milling
If you’re ordering a custom aluminum component, be cautious about specifying 5052. While it’s a top performer in formed or welded applications, it’s poorly suited for machining. The softness and ductility that make it easy to bend are the same properties that make it difficult and expensive to machine.
For CNC-milled, turned, or precision-finished parts, Aluminum 6061-T6 remains the gold standard. At Approved Machining, we’ve machined thousands of 6061 parts across industries from aerospace to industrial automation, and we know how to extract maximum performance from this highly capable alloy.
Need help choosing the right material for your next project? Contact us today and we’ll make sure your part is engineered for manufacturability and machined to perfection.