The forge or hammer mill was the workshop where the hot metal is shaped by hammering or rolling. Early forges comprised a finery hearth and a chafery, each with its own air bellows, and tilt hammers. Brittle cast-iron pigs were converted into malleable wrought iron and forged (shaped) bars of various sizes suitable for use by blacksmiths as the basis for iron structures. Waterwheels provided the power for operating the bellows and tilt hammers. Later forges included reverberatory type metal melting furnaces, shingling and steam hammers, rolling mills, power shears etc (William Jones, 1996, Dictionary of Industrial Archaeology).