Forging an Iron Chisel — The Cutting Tool That Shapes Stone, Wood, and Metal

The chisel is perhaps the most versatile tool ever forged. A blacksmith's cold chisel cuts iron on the anvil. A mason's point chisel dresses stone blocks. A carpenter's firmer chisel shapes timber joints. In every case, the principle is the same: a hardened steel or iron edge driven by a hammer blow concentrates force onto a line, splitting the material along that line.

An iron chisel is forged from a single bar of wrought iron: one end is drawn to a flat wedge for the cutting edge, the other end is left square as the striking head. The critical technique is case-carburising the cutting end — packing it in charcoal and heating it to absorb carbon, converting the surface layer from soft wrought iron into hardenable steel. This steel edge is then quench-hardened and tempered, giving the chisel a hard cutting face backed by a tough, shock-absorbing body.