believes that he accomplished this around 1816. According to Muir's book Reflections in Bullough's Pond, North "was the first arms maker to implement a number of machine production techniques, yet he cautiously halted his pursuit of mass-produced, interchangeable parts" whenever it became apparent that it was uneconomic. For some time, interchangeable-part manufacturing in metal continued to be a combination of machine-made parts and human skill in filing machined parts to precise size for such high-end uses as military weapons, in which interchangeable parts were worth paying for at high prices (they were worth high prices because an army on campaign could cannibalize damaged weapons for parts). As North's business grew, he moved it from Berlin to nearby Middletown. At about that time, North was sent to Captain John H. Hall, superintendent of the federal armory at Harpers Ferry, Virginia (now in West Virginia), to introduce his methods of achieving interchangeability. In 1828, North received a contract to produce 5,000 Hall rifles with parts interchangeable with those produced at Harpers Ferry. North had a 53-year contractual relationship with the United States Department of War. The report of Charles H. Fitch prepared for the 1880 Census credits North with a key role in developing manufacture with interchangeable parts. References Bibliography External links 1765 births 1852 deaths American inventors Machine tool builders People from Berlin, Connecticut