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Huntsman

Benjamin Huntsman

Achievements: Cast steel

Born: 1704; Barton-on-Humber, Lincolnshire, England

Died: 1776; Attercliffe, Yorkshire, England (Aged 72).

Field & Discipline: Industry; Manufacturing; Invention; Steel production

 Education: Unknown

Major Work: None

Life & Times:

In 1725 Huntsman set up as a clockmaker in Doncaster, England and within two years was caretaker of the town clock.  Huntsman frequently attempted to introduce improvements into the design of his clocks, but found himself hampered by the poor quality of the steel then available, which was not sufficiently uniform for the production of clock springs and pendulums.

Like most manufacturers he was using “German steel” (either manufactured in England or imported from Austria or Westphalia), made by filling the chest of a furnace with alternate layers of iron ore and charcoal, covering this construction with a layer of sand, and then heating the chest to a red heat for several days so that carbon would be absorbed by the solid iron bars, turning them into the steel which was then the general raw material for the steel trade.However, because the carbon absorption was from the outside in, the outer layers of steel tended to be higher in carbon than the centre and, although the process was designed to make a more uniform steel, the end result was, in essence, layers of high and low carbon material interleaved with each other.

This “German steel” was suitable for the manufacture of knife blades and swords, because the hardened and tempered article contained hard bands which could then be sharpened into cutting edges, while the softer material gave flexibility and resistance to breakage, but for fine tools and clock springs its lack of uniformity was unsuitable.

In 1740, Huntsman moved to Handsworth, where there was a better supply of coke for fuel, and began experimenting in secret with a new steelmaking process based on a modification of the method used by brass-founders. Huntsman believed that if he could successfully melt down the raw steel in a crucible, then it should be possible to produce a uniform material by a thorough mixing of the iron and charcoal.

In the early 1740s, having constructed a new furnace and  a new type of crucible able to withstand the far higher temperatures (around 1,600C) needed to melt steel, he began experimenting.  After several years Huntsman eventually perfected his process:  using coke as fuel to generate intense heat,  he melted broken bars of blister steel, placing them with fluxes in two closed clay crucibles in a chamber lined and covered with fire-brick.  This was then heated by a high-temperature furnace fanned by a strong draught generated by the combination of a large cellar and a tall tower.Huntsman's process proved far less complex than those previously used for the production of steel, and as a result costs of production were reduced and output was increased.

By 1751, Huntsman had mastered steel making sufficiently to give up clock making and establish himself as a steel maker, moving to premises at Worksop Road, Attercliffe. He had immediately realized that this process could be used to make superior tools and cutlery, but was unable to interest the conservative Sheffield cutlers in using his steel for their products, as they disliked working with a material that was much harder than “German steel.”

Huntsman turned  to France, where he found a keen market for his product, and where the French cutlers promptly worked his steel into high-quality knives and razors, then exported to England.Huntsman did not patent, but preferred instead to keep his process secret, carrying out his smelting at night to avoid observation. He quickly became known throughout Europe asthe expert in the production of cast steel, and his works were visited by many important iron manufacturers, inventors and engineers from home and abroad, including [works visited by] Boulton*, [works visited by] John Harrison*, [works visited by] Darby*, and [works visited by] John Wilkinson*.

Meanwhile, during the 1750s, when the Sheffield cutlers found that their markets were being lost to the superior quality French cutlery, they tried to obtain a government order to prevent Huntsman exporting his crucible steel. Fortunately for Sheffield's development, they were unsuccessful in this attempt,  and just as Huntsman was contemplating a move to Birmingham, the Sheffield cutlers started using his steel.Demand for Huntsman steel increased rapidly and in 1770 he moved his factory to a new site at in Attercliffe in the Don Valley, an area which later became the main location for the huge special-steel making industry of Sheffield.

Assessment: His method was the most significant development in steel production up to that time, and was used to produce cast steel for engineering tools, knives, and other cutting instruments.

Oneliner: Benjamin Huntsman,  inventor of cast steel

Bibliography:

Video Conn 2-14:

"Bright Ideas" – gin and tonic was invented to combat malaria in British colonies like Java, which leads us to Geneva, where cleanliness is an obsession. Here, tonic water was sealed with a disposable bottle cap, and razors became disposable, leading us to Huntsman's steel, invaluable for making clock springs. We take a little trip through lighthouses, the education of orphans, psycho-physics, the law of the just noticeable difference, which is the idea behind stellar magnitudes, which leads us to discovering the size of the universe.