English inventor of crucible (crucible process), or cast, steel, which was more uniform in composition and more free from impurities than any steel previously produced. His method was the most significant development in steel production up to that time.

A clockmaker and instrument maker in Doncaster, Yorkshire, Huntsman opened (c. 1740) a plant in Sheffield, where he produced steel for clock and watch springs. Considering his steel too hard, Sheffield cutlers would not use it until they discovered that continental European cutlery made from Huntsman's steel was superior to their products. While Huntsman maintained extreme secrecy at his foundry, he did not patent his process, and it was later copied by others.