Tool-Steel Bar: Crucible Steel Drawn Out at a Cherry-Red Heat

Sheffield poured its crucible cast steel into octagonal or rectangular iron moulds and drew the ingots out into rods under the tilt hammer. That bar, eight-sided or square, was the stock for chisels, punches, files and blades. Andrew Ure's 1839 warning still holds: this steel must not go much above a cherry-red heat, or it turns brittle. The picture: a water-driven tilt hammer at Abbeydale Industrial Hamlet, Sheffield.