Nasmyth steam hammer, by James Nasmyth, Patricroft, Salford, Manchester, England, 1845-1855. It was installed at the Royal Mint until 1933.

The steam hammer was a tool for shaping large pieces of wrought iron. By 1839, when James Nasmyth devised the steam hammer, the increasing scale of nineteenth century engineering was outstripping available forging techniques. The tool was a direct response to these new demands and one intended application was forging the huge paddle shaft planned for Brunel’s steamship Great Britain. Although the Great Britain was altered during building to use screw propulsion rather than paddles, the hammer was completed in 1843 and found a wide range of uses.

Nasmyth was a highly talented machine builder, but he did not invent the steam hammer, nor was he the first to build one. In 1843, an acrimonious dispute arose between him and the engineer François Bourdon from the famous Le Creusot ironworks as to who was first with the idea. However, Nasmyth’s ability as a self-publicist managed to obscure the origins of the invention. He promoted the new tool with energy, usually attending in person at the starting-up of a new hammer, or showing that it was so controllable that it could merely crack the top of an egg placed in a wine glass.

This hammer is a small version of the giant machines Nasmyth built for heavy engineering and was installed in the workshops of the Royal Mint, where it was used in the making and maintenance of machinery and tools.