The American System of Manufactures, which developed during the nineteenth century, used a series of machine tools operated by skilled workers to manufacture objects. The American System transferred much of the hand skill of craft workers into the machine tools, and broke up the production process such that a single craftsman no longer made each complete object. The skilled machine operators still had considerable control over the production process, however, due to their knowledge of the machines. The goal of the American System was the production of standardized, interchangeable parts, but this remained elusive until the breakthroughs of Henry Ford and others.