Steel door knocker, 1996.
© Science Museum / Science & Society Picture Library
Although steel is very hard, delicate shapes can be made without large industrial machines. Intricate pieces like this door knocker are made by heating the steel in a coke-fuelled forge and shaped using purpose-made tools. This knocker took a very experienced blacksmith several weeks to make as it contains a variety of shapes including acorns and empty cups which each required a different mould. Designed and made by Paul Allen, Rural Development Commision.