[2] Like his contemporary Simeon North, Hall began using this mill power to run machine tools and achieve the dimension controls necessary for interchangeable parts.
He employed metal-cutting machines attached with cutters and saws in the place of the standard heavy labor, made from cast-iron frames to ensure structural integrity and minimize vibrations from the mill’s belts.
[1] When a three-man committee deployed by the US Ordnance Department to verify Hall’s process in fulfilling his rifle contract visited Harpers Ferry, they were floored by his results, and especially the machines.
They lauded Hall’s “system, in the manufacture of small arms, [as] entirely novel,” and one which could yield “the most beneficial results to the Country, especially, if carried into effect on a large scale”.
[5] Hall's cutting machines were designed for simplicity, to the point that “activity [was] more necessary than judgment” and young boys or “common hands” could successfully run them.
Hall himself even claimed “one boy by the aid of these machines can perform more work than ten men with files, in the same time, and with greater accuracy”.
Hall's methods transformed the United States from an economy of workshop craftsmen to a nation of industrialized mass production.