Exactly: How Precision Engineers Created the Modern World. Simon Winchester

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       John “Iron-Mad” Wilkinson, whose patent for boring cannon barrels for James Watt marked both the beginning of the concept of precision and the birth of the Industrial Revolution.

      John Wilkinson was born into the iron trade. His father, Isaac, originally a Lakeland shepherd, discovered by fortuitous chance the presence of both ore and coal on his pastures and so became in time an ironmaster, a trade very much of its time. The word describes the owner of a family of furnaces, and one who used them to smelt and forge iron from its ore with either charcoal (which stripped England of too-large tracts of forest) or (as an environmentally responsible response) coal that had been half burned and transmuted into coke. John himself, uncomfortably born, it was said, bumping along in a market cart while his mother was en route to a country fair, became fascinated by white heat and molten metal and the whole process of taking mere rocks that lay underground and creating useful things simply by violently heating and hammering them. He learned the trade at the various places in the English Midlands and the Welsh Marches where his father settled down, and was sufficiently adept that by the early 1760s, by now married into money and owning a considerable foundry in the Welsh-English borderland village of Bersham, he began in earnest the production, according to the firm’s first ledger, of “calendar-rolls, malt mill rolls, sugar rolls, pipes, shells, grenades and guns.” It was the final item on the list that would give the tiny village of Bersham, along with the man who would become its most prosperous resident and its largest employer, a unique place in world history.

      Bersham, which lies in the valley of the River Clywedog, enjoys an indisputable though half-forgotten role both in the founding of the Industrial Revolution and in the story of precision. For it is here that on January 27, 1774, John Wilkinson, whose local furnaces, all fired by coal, were producing a healthy twenty tons of good-quality iron a week, invented a technique for the manufacture of guns. The technique had an immediate cascade effect very much more profound than those he ever imagined, and of greater long-term importance, I would argue, than the much more famed legacies of his friend and rival Abraham Darby III, who threw up the still-standing great Iron Bridge of Coalbrookdale that attracts tourist millions still today, and is regarded by most modern Britons as the Industrial Revolution’s most potent and recognizable symbol.

      Wilkinson filed a patent, Number 1063—it was still quite early in the history of British patents, which were first issued in 1617—with the title “A New Method of Casting and Boring Iron Guns or Cannon.” By today’s standards, his “new method” seems almost pedestrian and an all-too-obvious improvement in cannon making. In 1774, however, a time when naval gunnery all over Europe was enjoying a period of sudden scientific improvement in both technique and equipment, Wilkinson’s ideas came as a godsend.

      Up until then, naval cannons (most particularly the thirty-two-pound long gun, a standard on first-rate ships of the line in the Royal Navy, often ordered a hundred at a time when a new vessel was launched) were cast hollow, with the interior tube through which the powder and projectile were pushed and fired preformed as the iron was cooling in its mold. The cannon was then mounted on a block and a sharp cutting tool advanced into it at the end of a long rod, with the idea of smoothing out any imperfections on the tube’s inner surface.

      The problem with this technique was that the cutting tool would naturally follow the passage of the tube, which may well not have been cast perfectly straight in the first place. This would then cause the finished and polished tube to have eccentricities, and for the inner wall of the cannon to have thin spots where the tool wandered off track. And thin spots were dangerous—they meant explosions and bursting tubes and destroyed cannon and injuries to the sailors who manned the notoriously dangerous gun decks. The poor quality of early eighteenth-century naval artillery pieces led to failure rates that decidedly alarmed the sea lords at Admiralty headquarters in London.

      Then came John Wilkinson and his new idea. He decided that he would cast the iron cannon not hollow but solid. This, for a start, had the effect of guaranteeing the integrity of the iron itself—there were fewer parts that cooled early, for example, as would happen if there was a form installed to create the inner tube. A solid cylindrical chunk of iron, heavy though it might have been, could, if carefully made, come out of the Bersham furnaces without the air bubbles and spongy sections (“honeycomb problems,” as they were called) for which hollow-cast cannon were then notorious.

      Yet the true secret was in the boring of the cannon hole. Both ends of the operation, the part that did the boring and the part to be bored, had to be held in place, rigid and immovable. That was a canonical truth, as true today as it was in the eighteenth century, for to cut or polish something into dimensions that are fully precise, both tool and workpiece have to be clasped and clamped as tightly as possible to secure immobility. Moreover, in the specific case of gun barrels, there could be no allowable temptation for the boring tool to wander while the bore was being made. This was the reason the cannons were cast solid rather than hollow. To do otherwise was to risk explosive catastrophe.

      In the first iteration of Wilkinson’s patented process, this solid cannon cylinder was set to rotating (a chain was wrapped around it and connected to a waterwheel) and a razor-sharp iron-boring tool, fixed onto the tip of a rigid base, was advanced directly into the face of the rotating cylindrical workpiece. This created a brand-new hole, straight and precise, as the boring tool was pushed directly into the iron. “With a rigid boring bar and the bearing true,” wrote a recent biographer of Wilkinson’s, somewhat poetically, “accuracy was bound to ensue.” In later versions, it was the cannon that remained fixed and the tool, itself now connected to the waterwheel, that was turned. In theory, and provided that the turning bar itself was rigid; that it was supported at both ends and so maintained its rigidity; and that, as it was advanced into the hole it was boring into, the cylinder face did not bend or turn or hesitate or waver in any way, a hole of great accuracy could be created.

      Indeed, that is just what was obtained. Cannon after cannon tumbled from the mill, each accurate to the measurements the navy demanded, each one, once unbolted from the mill, identical to its predecessor, each one certain to be the same as the successor that would next be bolted onto it. The new system worked impeccably from the very start, encouraging Wilkinson to apply for and indeed receive his famous patent.

      Instead of an eccentrically drilled-out version of a previously cast hole in a cannon barrel that was already peppered with flaws and weak spots, and which, if it fired at all, would hurl the ball or chain shot or shell wildly through the air, the Royal Navy now received from the Bersham works wagonloads of guns that had a much longer shelf life and would fire their grapeshot or canister shot or explosive shells exactly at their intended target. The improvements were all thanks to the efforts of John Wilkinson, ironmaster. Already a wealthy man, Wilkinson prospered mightily as a result: his reputation soared, and new orders flooded in. Soon, his ironworks alone were producing fully one-eighth of all the iron made in the country, and Bersham was firmly set to be a village for the ages.

      Yet what elevates Wilkinson’s new method to the status of a world-changing invention, and Bersham’s consequent elevation from the local to the world stage, would come the following year, 1775, when he started to do serious business with James Watt. He would then marry his new cannon-making technique, though this time without a brand-new patent, incautiously, with the invention that Watt was just then in the throes of completing, the invention that would ensure that the Industrial Revolution and much else besides and beyond were powered by the cleverly harnessed power of steam.

      The principle of a steam engine is familiar, and is based on the simple physical fact that when liquid water is heated to its boiling point it becomes a gas. Because the gas occupies some 1,700 times greater volume than the original water, it can be made to perform work. Many early experimenters realized this. A Cornish ironmonger named Thomas Newcomen was the first to turn the principle into a product: he connected a boiler, via a tube with a valve, to a cylinder with a piston, and the piston to a beam on a rocker. Each time steam from the boiler entered СКАЧАТЬ