Threaded Copper Screws, Bolts, Nuts, and Washers

Threaded copper fasteners are most commonly specified in marine hardware (where saltwater corrosion resistance is essential), electrical grounding systems (where conductivity matters), and chemical or food-processing equipment where iron contamination must be avoided. Architectural and decorative applications also use copper fasteners for their appearance and patina characteristics.

When a fastener is made of mixed metals, classification generally follows the essential character of the article, which CBP typically determines by the predominant material by weight or value. A bolt with a copper body and minor steel components would likely remain in the copper fastener heading, but a mixed-material article should be reviewed carefully — and a binding ruling sought if the composition is ambiguous.