[citation needed] In the 1970s, Smith made a large contribution to our understanding of how interchangeability of mechanical parts went from concept to realization.
During 1815–1834, Hall had assembled elements of standardization and combined it with new machine designs and effective team management to realize the long-desired goal of true parts interchangeability.
Hall's innovative breechloading US Rifle Model 1819 was the first product ever made in large numbers whose components could be freely exchanged with one another and still function.
Smith's research on Hall's work at Harpers Ferry has put the Maine craftsman back in his proper position in the industrial pantheon.
Merritt Roe Smith's Harpers Ferry and the New Technology has provided an outstanding study of Hall's achievements."