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Is Brass Harder Than Aluminum

When engineers and buyers compare materials for precision CNC parts, a common question is, is brass harder than aluminum? The short answer is that most common free machining brasses are harder than the aluminum alloys typically used for CNC machining. The long answer is more nuanced and depends on alloy selection, part geometry, and performance requirements.

How Hardness Compares Between Brass and Aluminum

In general, common brass alloys like C360 (free machining brass) have a higher Brinell hardness than popular aluminum grades such as 6061 and 7075. That means brass usually offers a more resistant surface and better wear characteristics in many applications.

However, hardness is only one piece of the puzzle. When we help customers choose between brass machining and aluminum CNC machining, we also look at:

  • Required strength and stiffness
  • Wear and friction conditions
  • Corrosion environment
  • Weight targets
  • Cost and material availability
  • Tolerances and surface finish requirements

What Brass Hardness Means in Real Applications

Because brass is typically harder than aluminum, it often performs well in parts that see frequent contact or sliding movement. Common examples include:

  • Valve components and fluid fittings
  • Gears, bushings, and bearing-style parts
  • Electrical and electronic hardware
  • Precision threaded components and connectors

Brass also machines very cleanly, which allows our team to hold tight tolerances and achieve excellent surface finishes on small, intricate features. That combination of hardness, machinability, and stability makes brass a strong choice for many production parts that need consistent performance over time.

When Aluminum Is a Better Choice Than Brass

Even though brass is usually harder, aluminum is often the better engineering choice when weight, cost, or corrosion resistance are the primary drivers. Compared to brass, aluminum:

  • Is significantly lighter, which matters for aerospace and motion systems
  • Can be very cost effective for larger or higher volume parts
  • Performs well in many outdoor and marine environments, especially with the right finish

For many structural parts, housings, and enclosures, the hardness of brass is not required. In those cases, aluminum’s balance of strength, machinability, and weight makes it an ideal choice. You can learn more about how we use aluminum in production on our aluminum CNC machining page.

Hardness Is Only One Machinability Factor

From a machinist’s perspective, hardness affects cutting tool life and the best way to fixture a part, but it is not the only factor. Our CNC machining capabilities include multi axis milling, turning, and complex part production in both brass and aluminum, so we look at the full picture:

  • Chip formation: Both brass and many aluminum alloys produce good chips when properly tooled.
  • Surface finish: Brass often provides a very smooth finish for sealing surfaces and cosmetic faces.
  • Dimensional stability: Brass’s hardness and density can help with stable, repeatable dimensions on small or thin walled parts.
  • Secondary operations: Plating, anodizing, grinding, and EDM may influence which material is best.

Because we also provide specialty processes like Wire EDM, we can support complex geometries and tight tolerances whether your design calls for brass, aluminum, or another alloy from our metals and materials we machine lineup.

How to Decide Between Brass and Aluminum for Your Part

If you are wondering whether the extra hardness of brass is worth it for your design, these questions can help guide the choice:

  • Will the part experience repeated sliding, impact, or wear?
  • Is electrical conductivity important?
  • Is weight a critical factor in the system?
  • Does the design rely on very fine threads, small features, or tight sealing surfaces?
  • What are your cost and volume targets?

In many cases, both brass and aluminum can work, but one will give you a better balance of performance, manufacturability, and total cost. Our engineering focused team is happy to review prints, discuss failure modes, and recommend the material that aligns with your priorities.

Work With a Precision CNC Partner for Brass and Aluminum

C&H Machine is a U.S. based precision machining company serving OEMs in demanding industries. Whether you need production quantities in brass, aluminum, or other alloys, we combine disciplined quality systems with experienced programmers and machinists to deliver reliable, repeatable parts.

To talk about whether brass’s higher hardness is right for your design, or to compare options with aluminum, send us your drawings and requirements. You can:

If you are not sure where to start, share your application details and performance goals. We will help you decide whether the added hardness of brass or the lighter weight of aluminum is the better fit for your part and your production program.