Burning coal in an electric forge. A forge is a hearth used for heating metals, or the workplace (“smithy”) where the hearth is located. The forge is used by the smith to heat a piece of metal to a temperature where it becomes easier to shape, or to the point where work hardening no longer occurs. The metal (known as the “workpiece”) is transported to and from the forge using tongs, which are also used to hold the workpiece on the smithy’s anvil while the smith works it with a hammer. Finally the workpiece is transported to the slack tub, which rapidly cools the workpiece in a large body of water.