John Wilkinson

John Wilkinson bored the cylinders that made the steam engine work, and was known in his lifetime as Iron-Mad Wilkinson. He was an ironmaster's son who took over the family works and spent his life finding new things to make out of iron. His patent of 1774 was for a machine to bore cannon from a solid casting, with the boring bar supported at both ends so that it could not wander - and the same machine could bore a cylinder true to within the thickness of a worn shilling. That tolerance is the reason James Watt's separate-condenser engine became a product rather than a demonstration: Watt had the principle by 1769 and could not get a cylinder made accurately enough to hold steam until Wilkinson did it. Wilkinson took the first engine for his own works, and for years his machines bored every cylinder Boulton and Watt sold. He built the first iron boat in 1787, against general conviction that it would sink, supplied the ribs for the Iron Bridge at Coalbrookdale, made iron pipes for the Paris water supply, and had himself buried in an iron coffin, having kept it in his office and shown it to visitors. He also sold cannon to France while Britain was at war with it, which was investigated and not prosecuted. His brother and his business partners spent years in litigation with him, and the works were broken up after his death by a dispute over his will and his illegitimate children. He issued his own coinage, with his head on it, when small change was short. Boulton and Watt eventually discovered he had been building unlicensed copies of their engine and selling them, which ended the partnership.

• Lived: 1728 CE – 1808 CE
• Nationality: British
• Roles: inventor, businessman