The American system of manufacturing was a set of manufacturing methods that evolved in the 19th century. The two notable features were the extensive use of interchangeable parts and mechanization for production, which resulted in more efficient use of labor compared to hand methods. The system was also known as armory practice because it was first fully developed in armories, namely, the United States Armories at Springfield in Massachusetts and Harpers Ferry in Virginia (later West Virginia), inside contractors to supply the United States Armed Forces, and various private armories. The name "American system" came not from any aspect of the system that is unique to the American national character, but simply from the fact that for a time in the 19th century it was strongly associated with the American companies who first successfully implemented it, and how their methods contrasted (at that time) with those of British and continental European companies. In the 1850s, the "American system" was contrasted to the British factory system which had evolved over the previous century. Within a few decades, manufacturing technology had evolved further, and the ideas behind the "American" system were in use worldwide. Therefore, in manufacturing today, which is global in the scope of its methods, there is no longer any such distinction.
The American system involved semi-skilled labor using machine tools and jigs to make standardized, identical, interchangeable parts, manufactured to a tolerance, which could be assembled with a minimum of time and skill, requiring little to no fitting.
Since the parts are interchangeable, it was also possible to separate manufacture from assembly and repair—an example of the division of labor. This meant that all three functions could be carried out by semi-skilled labor: manufacture in smaller factories up the supply chain, assembly on an assembly line in a main factory, and repair in small specialized shops or in the field. The result is that more things could be made, more cheaply, and with higher quality, and those things also could be distributed further, and lasted longer, because repairs were also easier and cheaper. In the case of each function, the system of interchangeable parts typically involved substituting specialized machinery to replace hand tools.
Interchangeability of parts was finally achieved by combining a number of innovations and improvements in machining operations and machine tools, which were developed primarily for making textile machinery. These innovations included the invention of new machine tools and jigs (in both cases, for guiding the cutting tool), fixtures for holding the work in the proper position, and blocks and gauges to check the accuracy of the finished parts. | Joseph Whitworth, 1854
Other characteristics
The American system contributed to efficiency gains through division of labor. Division of labor helped manufacturing transition from small artisan's shops to early factories. Key pieces of evidence supporting efficiency gains include increase in firm size, evidence of returns to scale, and an increase in non-specialized labor. The need for firms to train uneducated people to perform only one thing in the productivity chain allowed for the use of non-specialized labor. Women and children were employed more frequently within larger firms, especially those producing furniture and clothing..
History
In the late 18th century, French General Jean Baptiste Vaquette de Gribeauval suggested that muskets could be manufactured faster and more economically if they were made from interchangeable parts. This system would also make field repairs easier to carry out under battle conditions. He provided patronage to Honoré Blanc, who attempted to implement the Système Gribeauval, but never succeeded. This method of working did not catch on in general manufacturing in Britain for many decades, and when it did it was imported from America, becoming known as the American System of Manufacturing, even though it originated in England.
The Lowell system is also related to the American system during this time. It emphasized procuring, training, and providing housing and other living necessities for the workforce, as well as using semi-automated machines in a centralized factory building or complex.
Gribeauval's idea was conveyed to the US by two routes. First, Blanc's friend Thomas Jefferson championed it, sending copies of Blanc's memoirs and papers describing his work to Secretary of War Henry Knox. Second, artillery officer Louis de Tousard (who had served with Lafayette) was an enthusiast of Gribeauval's ideas. Tousard wrote two influential documents after the American Revolution; one was used as the blueprint for West Point, and the other became the officer's training manual. By 1815 the idea of interchangeability was well established in the US government system of procurement; Congressional contracts stipulated this quality in muskets, rifles and pistols ordered after that date. Interchangeability of firearms parts at the U.S. armories was found to have been in use for a number of years by the time of the 1853 British Parliamentary Commissions Committee on Small Arms inquiry.
A critical factor in making interchangeable metal parts was the invention of several machine tools, such as the slide rest lathe, screw cutting lathe, turret lathe, milling machine and metal planer. One of the most important and versatile of these machine tools was David Wilkinson's lathe, for which he received a $10,000 award from the government of the United States.
Eli Whitney is generally credited with the idea and the practical application, but both are incorrect attributions. Based on his reputation as the inventor of the cotton gin, the US government gave him a contract in 1798 for 10,000 muskets to be produced within two years. It actually took eight years to deliver the order, as Whitney perfected and developed new techniques and machines. In a letter to Treasury Secretary Oliver Wolcott apologizing for the delays, Whitney wrote:
Whitney did use machinery; however, there is no evidence that he produced any new type of metalworking machinery. Late to adopt the interchangeable system were Singer Corporation sewing machine (1870s), reaper manufacturer McCormick Harvesting Machine Company (1870s–80s) as well as locomotive makers. Large scale of production of bicycles in the 1880s used the interchangeable system.