The American system of manufacturing evolved over the 19th century. The system featured a set of manufacturing methods that involved semi-skilled workers using machine tools and jigs to produce standardized and identical interchangeable parts for achieving better specified tolerances. These methods produced parts that could be assembled and fitted together with minimal mismatches and reworked within a limited time, and with limited skills and labour. This system introduced the concept of quality assurance in manufacturing. Because it was American companies that first successfully adopted the system, it was called the American system of manufacturing.
The demand for the manufacturing of interchangeable identical parts initiated the development of parts production by semi-skilled labour with the assistance of accurate precision machines and tools. As a result, there was reduced demand for fully skilled workers. Such manufacturing process development became the dominant management strategy and resulted in the division of labour for higher productivity and product quality standards.
The use of machinery in operations and machine tools brought about quality benefits such as consistency in interchangeability of parts and higher productivity. This then led to the concept of a quality assurance system. Such advantages encouraged manufacturers to come up with more ideas for innovations. These same advantages also led to the development of new machine tools, jigs and fixtures for producing more accurate and higher quality products.