Q. I am designing a power lead connector for a large earth moving vehicle. The connector is crimped to copper wires to make electrical contact. I propose to machine this component from brass CW606N (CZ131) bar followed by tin plating. Any advice please?

The brass selected is free machining with good ductility and is an excellent choice for this application. The component should be annealed in the range 400 to 600^oC to give maximum ductility to ensure that the crimping will be successful. There is no need for tin plating; in this environment the brass will darken with time with no loss of properties.

It is important that the lead content (1.6 to 2.5%) of this brass is maintained at the specification level in all of the connectors since higher lead levels may lead to cracking on crimping. With this in mind, source brass from the UK or Europe where full certification will be available.