Brass C360: The Free-Machining Brass

C360, known as free-machining brass, is the brass on OpusFab’s CNC material list. A small lead content makes it the most machinable metal in the catalogue: it cuts fast, produces short chips that clear cleanly, and leaves an excellent surface finish straight off the tool.

Why choose brass

• Machinability: the fastest metal we offer to cut, which means short cycle times and a good part price, especially on turned parts
• Corrosion resistance: brass resists moisture and many chemicals naturally, with no coating required for indoor or mild outdoor use
• Electrical conductivity: a standard material for terminals, connectors, and electrical hardware
• Appearance: a warm gold colour that suits decorative and visible parts

Typical uses: fittings, valves, plumbing hardware, electrical terminals and connectors, gears and clockwork, and decorative or cosmetic parts.

Design and quoting notes

C360 machines to the same CNC tolerance tiers as our other metals: Standard (±0.05mm) and Precision (±0.01mm). Threads, small features, and fine surface detail all cut cleanly thanks to the short chips, so brass suits detailed turned and milled parts. Because cycle time drives most of the CNC price, C360 parts often come out cheaper than the same geometry in a slower-cutting metal. Follow the metal minimums in Minimum radius and wall thickness for thin walls and sharp internal corners.

Where brass does not fit

• Structural work: brass is not a high-strength material. For load-bearing parts, use steel, stainless, aluminium, or titanium.
• Weight-sensitive parts: brass is dense, nearly three times aluminium by volume.
• High-purity or food applications: the lead content that makes C360 machine so well rules it out of some regulated uses.

Tarnish and finishes

Brass tarnishes over time, dulling from gold to brown where it is handled or exposed to air. Options:

• Leave it Raw (As-Machined) and accept a natural patina, which many decorative parts wear well.
• Powder coat it any Pantone colour for an opaque, durable finish.
• PVD coat it for a thin, hard metallic surface that locks in the look.
• Sandblast it for a uniform matte texture.

See the Surface finishes overview for what each finish does.

When to choose C360

• Fittings, valves, and turned hardware in quantity, where machinability drives the price down
• Electrical terminals, connectors, and grounding hardware
• Visible parts that should look like brass
• Any part where fast cycle times matter more than maximum strength

For the full metal list, see Materials overview.