The steam hammer

In 1837, the Great Western Steam Company was experiencing many problems forging the paddle shaft of the SS Great Britain; when even the largest hammer was tilted to its full height its range was so small that if a really large piece of work were placed on the anvil, the hammer had no room to fall, and in 1838 the company's engineer (Francis Humphries) wrote to Nasmyth: "I find there is not a forge-hammer in England or Scotland powerful enough to forge the paddle-shaft of the engine for the Great Britain! What am I to do?”

Nasmyth thought the matter over and seeing the obvious defects of the tilt-hammer (it delivered every blow with the same force) sketched out his idea for the first steam hammer. He kept his ideas for new devices, mostly in drawings, in a "Scheme Book" which he freely showed to his foreign customers. Nasmyth made a sketch of his steam hammer design dated 24 November 1839, but the immediate need disappeared when the practicality of screw propellers was demonstrated and the Great Britain was converted to that design.^[3]

The French engineer François Bourdon came up with the similar idea of what he called a "Pilon" in 1839 and made detailed drawings of his design, which he also showed to all engineers who visited the works at Le Creusot owned by the brothers Adolphe and Eugène Schneider.^[3] However, the Schneiders hesitated to build Bourdon's radical new machine. Bourdon and Eugène Schneider visited the Nasmyth works in England in the middle of 1840, where they were shown Nasmyth's sketch. This confirmed the feasibility of the concept to Schneider.^[4] In 1840 Bourdon built the first steam hammer in the world at the Schneider & Cie works at Le Creusot. It weighed 2,500 kilograms (5,500 lb) and lifted to 2 metres (6 ft 7 in). The Schneiders patented the design in 1841.^[5]

In April 1842 Nasmyth visited France with a view to supplying the French arsenals and dockyards with tools and while he was there took the opportunity to visit the Le Creusot works. On going round the works, he found the steam-hammer at work. By his account, Bourdon took him to the forge department so he might, as he said, "see his own child". Nasmyth said "there it was, in truth–a thumping child of my brain!"^[3] Nasmyth patented his design in June 1842 using money borrowed from his sister Anne's husband William Bennett.^[6] He built his first steam hammer later that year in his Patricroft foundry.^[7] In 1843 a dispute broke out between the two engineers over priority of invention of the steam hammer.^[8]

James Nasmyth's patent steam hammer as illustrated in Tomlinson's Cyclopaedia of Useful Arts, 1854

By using the hammer, production costs could be reduced by over 50 percent, while at the same time improving the quality of the forgings produced.

The first hammers were of the free-fall type but they were later modified, given power-assisted fall. Up until then, the invention of Nasmyth's steam-hammer, large forging, such as ships' anchors, had to be made by the "bit-by-bit" process, that is, small pieces were forged separately and finally welded together. A key feature of his machine was that the operator controlled the force of each blow. He enjoyed showing off its capability by demonstrating how it could first break an egg placed in a wine glass, without breaking the glass, which was followed by a full-force blow which shook the building. Its advantages soon became so obvious that before long Nasmyth hammers were to be found in all the large workshops all over the country.

An original Nasmyth hammer now stands facing Nasmyth's Patricroft foundry buildings (now a 'business park'). A larger Nasmyth & Wilson steam hammer stands in the campus of the University of Bolton.

Nasmyth subsequently applied the principle of his steam hammer to a pile-driving machine which he invented in 1843. His first full scale machine used a four-ton hammer-block, and a rate of eighty blows per minute. The pile driver was first demonstrated in a contest with a team using the conventional method at Devonport on 3 July 1845. He drove a pile 70 feet long and 18 inches squared in four and a half minutes, while the conventional method required twelve hours. This was a great success, and many orders for his pile driver resulted. It was used for many large scale constructions all over the world in the next few years, such as the High Level Bridge at Newcastle upon Tyne and the Nile barrage at Aswan, Egypt (Aswan Low Dam).

By 1856 a total of 490 hammers had been produced which were sold across Europe to Russia, India and even Australia, and accounted for 40% of James Nasmyth and Company's revenues.

Other inventions

The milling machine built by James Nasmyth between 1829 and 1831, with indexing fixture.

Apart from the steam hammer, Nasmyth created several other important machine tools, including the shaper, an adaptation of the planer which is still used in tool and die making. Another innovation was a hydraulic press which used water pressure to force tight-fitting machine parts together. All of these machines became popular in manufacturing, and all are still in use in modified form.

Nasmyth was also one of the first toolmakers to offer a standardised range of machine tools; before this, manufacturers constructed tools according to individual clients' specifications with little regard to standardisation, which caused compatibility problems. Nasmyth was arguably the last of the early pioneers of the machine tool industry.

Among Nasmyth's other inventions, most of which he never patented, were a means of transmitting rotary motion by means of a flexible shaft made of coiled wire, a machine for cutting key grooves, self-adjusting bearings, and the screw ladle for moving molten metal which could safely and efficiently be handled by two men instead of the six previously required. Nasmyth's idea of a steam ram for naval warfare was never put into production.

In 1844 he, together with engineer Charles May, patented the first Vacuum brake.^[9]

Although milling machines were no longer novel by 1830, an example built by Nasmyth around that time stands out for its prescience. It was tooled to mill the six sides of a hex nut that was mounted in a six-way indexing fixture.^[10]

He also worked on a project for the conversion of iron which was not dis-similar to that which was eventually patented by Henry Bessemer. A reluctant patentor, and in this instance still working through some problems in his method, Nasmyth abandoned the project after hearing of Bessemer's ideas in 1856. Bessemer, however, acknowledged the efforts of Nasmyth by offering him a one-third share of the value of his patent for the eponymous Bessemer process. Nasmyth turned it down as he had decided to retire.^[11]

Later life

Drawing of a crater on the surface of the Moon by Nasmyth

Nasmyth retired from business in 1856 when he was 48 years old, as he said "I have now enough of this world's goods: let younger men have their chance". He settled down near Penshurst, Kent, where he renamed his retirement home "Hammerfield" and happily pursued his various hobbies including astronomy. He built his own 20-inch reflecting telescope, in the process inventing the Nasmyth focus, and made detailed observations of the Moon. He co-wrote The Moon: Considered as a Planet, a World, and a Satellite (1874) with James Carpenter (1840–1899). This book contains an interesting series of "lunar" photographs: because photography was not yet advanced enough to take pictures at very high magnification directly of the Moon itself, Nasmyth built plaster relief scale models based on his visual observations of the Moon and then photographed the models under electric illumination, replicating the shadows of the topographic contours he observed on the Moon. A crater on the Moon is named after him.

He was happily married to his wife Anne, from Woodburn, Yorkshire, for 50 years, until his death. They had no children.

They are buried in the north section of the Dean Cemetery in western Edinburgh. The huge memorial stands at the east end of the main east–west path, with the path dividing around it. The monument holds a well-carved model of his steam hammer. James' mother, Barbara Foulis (1765-1848) is buried with them. The monument also stands as a memorial to his brother, Patrick Nasmyth (1787-1831)