American system of manufacturing

• 1. Introduction

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  The American system of manufacturing began not in a factory, but in an armory. At the United States Armories at Springfield, Massachusetts and Harpers Ferry, Virginia, workers in the 19th century were solving a problem that had bedeviled armies for generations: what do you do when a musket breaks in the field? The answer they arrived at would reshape how every complex object gets made. What if every part of every gun were identical to the corresponding part of every other gun? Then a broken trigger could be swapped from another weapon without any skilled fitting at all. That single idea, carried through to its practical conclusion, touched clocks and sewing machines and bicycles and eventually automobiles. The system these armories pioneered would come to be called the American system of manufacturing. But as this story unfolds, you will find that the idea was older than America itself, and that the men most celebrated for it were not always the ones who made it work.

• 2. Older Than America

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  Bronze crossbow triggers made during the Warring States period in East Asia were produced as interchangeable parts more than 2,200 years ago. Those ancient weapons demonstrate that the underlying logic was sound long before anyone in Europe or America thought to apply it to muskets. Venice offers another precedent. During the late Middle Ages, the Venetian Arsenal used pre-manufactured parts, assembly lines, and mass production to build ships at a rate of nearly one per day. That pace made it effectively the world's first factory. Mass production using truly interchangeable metal parts was first achieved in 1803, at Portsmouth Block Mills in Portsmouth Dockyard. Marc Isambard Brunel, Henry Maudslay, and Simon Goodrich accomplished it there for the British Royal Navy during the Napoleonic War, working under Brigadier-General Sir Samuel Bentham, the Inspector General of Naval Works. By 1808 that facility was turning out 130,000 sailing blocks a year. The method did not spread through British manufacturing. When it eventually appeared widely in Britain, it arrived as an import from across the Atlantic, already bearing the name the American system, despite its English origins.

• 3. The French Idea Travels West

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  French General Jean Baptiste Vaquette de Gribeauval proposed in the late 18th century that muskets built from interchangeable parts could be manufactured faster and repaired more easily in battle. He funded Honore Blanc to try to implement this Systeme Gribeauval, but Blanc never fully succeeded. The idea crossed to America by two channels. Thomas Jefferson, who had befriended Blanc, sent copies of Blanc's memoirs and papers to Secretary of War Henry Knox. Separately, artillery officer Louis de Tousard, a veteran who had served under Lafayette, carried Gribeauval's thinking into the documents he wrote after the American Revolution. One of Tousard's texts became the blueprint for West Point; the other became the officer training manual. Officers trained at West Point on that manual went on to staff the War Department. The War Department then established the armories at Springfield and Harpers Ferry and gave them a clear directive: solve the problem of interchangeability. That directive set in motion a decades-long competition between artisans, machinists, and contractors to turn a French general's idea into a working production system.

• 4. Who Really Got There First

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  Captain John H. Hall, an inside contractor at Harpers Ferry, claimed in a letter dated 1822 that he had achieved interchangeability that year. Historian David A. Hounshell credits Hall with the accomplishment. Historian Diana Muir argues the stronger case belongs to Simeon North, a Connecticut arms contractor building guns for the US Army. North invented the crucial milling machine in 1816, a full six years before Hall's letter. North also had a practical advantage: he worked closely with the Connecticut clock-making industry, the first sector to mass-produce complex machines from interchangeable parts at scale. By 1815, interchangeability was already a contractual requirement. Congressional contracts for muskets, rifles, and pistols ordered after that date explicitly required it. A British Parliamentary Commissions Committee on Small Arms, investigating the US armories in 1853, found that interchangeable firearms parts had been in use there for a number of years by then. Eli Whitney is often given credit for the whole system, but both the credit for the idea and the credit for the practical application are incorrect attributions. The US government awarded him a contract in 1798 for 10,000 muskets after his fame as the inventor of the cotton gin. It took him eight years to deliver an order promised within two. Whitney never expressed interest in interchangeability until 1800, when Treasury Secretary Oliver Wolcott showed him Blanc's memoirs.

• 5. Machinery, Labor, and Scale

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  Joseph Whitworth, an English machine tool manufacturer appointed as a British commissioner for the New York International Exhibition, toured manufacturers across several states and published a highly influential report on what he observed. He wrote that the laboring classes were comparatively few in number, but that this scarcity was counterbalanced by an eagerness to call in machinery in almost every department of industry. Wherever machinery could substitute for manual labor, he observed, it was universally and willingly applied. Whitworth attributed the prosperity of the United States to this condition of the labor market combined with superior education. The system depended on specific inventions to make metal parts precise enough to be truly identical. A critical cluster included the slide rest lathe, the screw cutting lathe, the turret lathe, the milling machine, and the metal planer. David Wilkinson's lathe was judged important enough that the US government awarded him $10,000 for it. Jigs for guiding cutting tools, fixtures for holding work in position, and precision gauges for checking finished parts all played roles. Division of labor followed naturally from interchangeability. Because parts were identical, manufacture, assembly, and repair could be separated entirely. Smaller factories up the supply chain could produce parts. A main factory could assemble on a line. Small shops or field teams could handle repairs without skilled fitting. Women and children were employed more frequently in larger firms, particularly those producing furniture and clothing, because the work no longer required years of craft apprenticeship.

• 6. From Armories to Industry

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  The War Department actively spread manufacturing knowledge beyond the armories by requiring contractors to open their shops to competitors. Armories shared techniques openly with private industry. Machinists trained in the armory system carried the methods with them when they moved to civilian employers. That migration reached American clockmakers and sewing machine manufacturers, including Wilcox and Gibbs and Wheeler and Wilson, both of which were using interchangeable parts before 1860. Later adopters included Singer Corporation, which switched its sewing machines to the interchangeable system in the 1870s, and McCormick Harvesting Machine Company, which followed in the 1870s and 1880s. Large steam engine manufacturers such as Corliss came to the system in the mid-1880s, as did locomotive makers around the same period. Bicycle production in the 1880s operated at large scale using the interchangeable system. The "American method" had also crossed back to Britain by the 1850s. When Colt executed an order for naval revolvers in Pimlico, and strikes among London and Birmingham gunmakers during wartime left the War Office needing workers with less specialized skills, the military response was to buy milling machines and install them at the Royal Small Arms Factory. That installation was complete by 1857. Ransom E. Olds began mass-producing the Curved Dash automobile in 1901, drawing the system into the emerging car industry. Henry Ford did not begin mass-producing cars until 1913, but the Ford plant mastered true interchangeability on the assembly line and produced standard model cars efficiently enough that the middle class could afford them.