Brass & Copper Machined Parts

Grades we machine

We machine six copper-family materials on this page, and the choice between them is a question of function rather than price. Free-cutting brass C360 is the most machinable copper alloy we run and the default for fittings, fasteners and turned parts. Copper C110 is specified where electrical and thermal conductivity are the point of the part. Bearing bronze covers the tin and lead bronze families chosen for low friction against a steel shaft, and aluminium bronze is the higher-strength choice for corrosion and wear resistance.

Brass 260 is the 70/30 cartridge brass, and it is on this page for a different reason than C360. It is more ductile and contains no lead, so it is the grade behind cold-formed, drawn and deep-drawn parts — terminals, shells, contact bodies and stamped hardware — where the metal has to flow rather than be cut. It machines less freely than C360, so specify it when formability or a lead-free composition is the reason for the grade, not when you simply want brass.

Copper 101 is the oxygen-free copper. It carries essentially the same conductivity as C110, and it is the grade to specify when the part will be brazed, welded or used in a vacuum or a hydrogen atmosphere, because the residual oxygen in ordinary tough-pitch copper can cause embrittlement at high temperature. For a plain current-carrying terminal where none of that applies, C110 is the more available and more economical choice.

Free-cutting brass C360 earns its name in the machine: it cuts at high spindle speeds with short, broken chips, holds fine detail, and threads cleanly with little burr, making it the workhorse for high-volume fittings, screws, nuts and valve components. When a buyer asks for “brass” without a grade, C360 is the working assumption we confirm in DFM feedback unless the drawing calls for something more specific. The cycle-time and tool-wear advantage keeps unit cost down on long runs.

Copper C110 is the conductivity grade. It is chosen for its electrical and thermal conductivity rather than its machinability, so it shows up in terminals, contacts, bus-bar components and heat sinks, where the material has to carry current or move heat. It is soft and ductile, so it smears and burrs more readily than brass — we plan tooling, speeds and chip control around that, and we keep threaded and contact faces clean. The extra care shows up in unit cost, which is why copper is reserved for parts where conductivity is the reason for the material.

Bearing bronze is the family we machine for bushings, sleeve bearings and wear plates, where the part runs against a steel shaft. The tin and lead bronzes in this family are chosen for their behaviour as a bearing surface — a bronze that runs smoothly against steel without galling or picking up on the shaft. The exact designation comes from your drawing; we confirm the specific alloy with our material suppliers before quoting. This is the “wear” choice in the trade-off.

Aluminium bronze is the strength grade in the copper family. It is specified where a copper-alloy part needs more mechanical capability together with good corrosion and wear resistance — pump components, valve parts and marine hardware are the common examples. It machines less freely than C360, but the payoff is a tougher part that still resists corrosion in seawater. As with bearing bronze, the designation comes from your drawing.

The choice, then, is functional: C360 for machinability and clean threads on fittings and turned fasteners, C110 when conductivity is the reason for the material, bearing bronze for a bearing or wear surface running against steel, and aluminium bronze for strength on top of the copper family’s corrosion and wear behaviour. If the drawing names a grade, that ends the discussion and we machine to it.

One honest point about cost: brass and copper both carry a material price premium over carbon steel, and on most parts that raw-material premium — not machining time — is the dominant cost driver. Free-cutting brass machines so quickly that cycle time is rarely the problem; the cost is in the metal itself, and copper sits higher still. Where the part allows it, we keep the total down: for high-volume brass fittings and fasteners we can run the blank through forging or heading through our vetted partner network before finish machining, and copper forging follows the same route for larger conductive components, then finish-machined to your drawing. Every grade is covered in our materials guide.

Machining characteristics

Brass is one of the most predictable metals to machine. It produces short, broken chips, cuts at high speeds with low tool wear, and holds ±0.01 mm on precision features without much difficulty. That makes it the low-cost option for high-volume turned parts, because cycle times stay short and tooling lasts.

Copper is the opposite in one respect: it is soft and ductile, so it smears and burrs more readily than brass. It needs sharp tooling, controlled speeds and feeds, and attention to chip control on threads and thin sections. We plan copper parts carefully in DFM feedback and keep burrs off threaded features and contact faces, because a burred terminal or contact will not seat properly.

Bronze splits the difference. Bearing bronze cuts more cleanly than pure copper but is more abrasive on the tool than free-cutting brass, so we balance speed against tool life. Aluminium bronze is the toughest of the four: it runs hotter and is harder on tooling, so we slow the cut and take controlled passes. In every case machining behaviour follows from the grade, which is why we confirm the grade in DFM feedback before quoting.

Both turn well on bar stock, so most round brass and copper parts go through CNC turning, with CNC milling for flats, slots and wrench features up to our 800 × 500 mm milling envelope. Brass rewards high spindle speeds and light finishing passes, while copper and the bronzes run best with sharp edges and a controlled chip.

Typical parts made from this material

Brass and copper cover a wide range of round and profiled parts:

• Fittings and adapters — threaded connectors in C360, where brass machines easily and resists corrosion.
• Terminals and contacts — C110 parts where conductivity is the whole reason for the material.
• Bushings and sleeves — bearing bronze wear and bearing surfaces that run against a steel shaft.
• Valve parts — brass valve bodies and seats, plus aluminium bronze where strength and wear resistance matter.
• Pump and marine components — aluminium bronze parts that need corrosion resistance with more strength than plain brass.
• Brass screws and nuts — high-volume turned fasteners in free-cutting brass.

Copper terminals and bus-bar components are turned or milled from bar, then plated where a solderable or corrosion-resistant surface is needed. Bronze bushings and wear plates are machined to ±0.01 mm on precision features and ISO 2768-m as the general tolerance. Orders start from 50 pieces per style and material, samples from 1 piece, and a material certificate (MTR) ships with every batch. Send the drawing through request a quote and we will confirm the grade, finish and lead time in DFM feedback.

Surface finishes that pair well

Brass and copper are often used bare, but a finish helps where tarnish, contact or solderability matters. Nickel plating is the standard choice for corrosion resistance and a bright appearance, tin plating where the part is soldered, and a clear coating where the natural colour should show through without tarnishing. Finishes are applied through our vetted partner network, managed under one quality process, and quoted with the same order.

Because brass and copper are soft, we keep plating thickness and masking in mind for threaded features so the finish does not change the fit, and we confirm masking and thickness in DFM feedback before plating begins. For more options, see our surface finishes guide, or the fastener specifications page for threaded fasteners.