CNC Lathe Turned Brass and Copper Connector Pins

Small pins are turned from drawn bar on CNC lathes with bar feeders, while very fine parts are run in the Swiss-type style with a guide bushing that supports the stock close to the tool. Cross holes, slots and crimp barrels are added with live tooling. Brass chips break cleanly, which allows high speeds and consistent finishes; copper is gummier, so we use sharper tools and lower feeds to avoid burrs.

Brass C36000/H59 is the economical choice: easy to machine, good conductivity and suitable for plating. Pure copper conducts roughly three times better than brass and is used for high-current contacts, but it machines slowly and tarnishes, so nickel or tin plating is common. Brass parts can be painted for color coding. Plating thickness, typically a few microns, is accounted for on mating diameters.

Pin diameters are checked with micrometers and pin gauges, lengths on height gauges, and cross-hole positions on an optical or CMM setup at first article. Critical dimensions are inspected on every part, and plating is checked for adhesion and coverage. Typical uses include PCB pins, battery terminals, socket contacts, grounding studs and sensor connectors.