In 1815 Springfield Armory superintendent Roswell Lee reported that fully half of the operations in the manufacture of muskets were performed on machines driven by water power. Machinery, whether powered directly from waterwheels or through line shafting connected to the machines by leather belting, brought significant improvement to the production capabilities of the Armory.
Machines eased the labor of men, but more importantly, their ability to perform repeated tasks and produce almost identical results made interchangeable parts a reality. As greater reliance was placed on machines, the cost of making a weapon was reduced and fewer skilled craftsmen were needed to do the work. Mass production was at hand.
The ERA OF WATER POWER exhibit area, cases 61, & 62
Transition to Interchangeable Parts
Before the introduction of techniques to make completely interchangeable parts for musket locks, the mechanism had to be completed using hand filing and finishing to final fit the parts. Since a part would work only in a lock to which it was fitted each part was parked to identify the mechanism to which it belonged. You can see these marks on the back side of the lock.
Three separate facilities, the Upper, Middle, and Lower Watershops, were built along a nearby stream to house heavy equipment such as trip hammers, forges, and barrel rolling machinery. Eventually, these three units were combined into one facility, known as the Water Shops, which remained in service until the end of the Armory.
In 1810 the only tasks performed by machine on the other parts of the musket were hollow milling of tumblers and slitting screws. By 1825 this list had expanded, to include:
Cutting the bands and side plate
Drawing the ramrod
Welding the bands
Boring the bayonet socket and the pan
Turning the bayonet socket and the head of the side screw
Milling the breech plug, bayonet socket, guard bow, band spring, side screw, tang screw, butt plate screw, guard screw, tumbler, bridle, cock pin, and lock screws
Slitting the side screw, tang screw, butt plate screw, lock screws, guard screw, cock pin
Threading the cock pin
Drilling the barrel vent, bands, guard plate & bow, lock plate, frizzen, cock, tumbler, bridle, sear, upper jaw, cock pin, main spring, frizzen spring, and sear spring
Punching the side plate, butt plate, and the square hole in the cock
Countersinking the guard plate and butt plate
Grinding the bayonet, ramrod, bands, guard, side plate, butt plate, and lock plate
Polishing the bayonet, ramrod, bands, swivel, guard, lock plate, trigger, side plate, band spring, butt plate
Turning, boring, inletting (the lock), fitting bands, fitting butt plate of the stock.
Extracted from: FORGE OF INNOVATION: An Industrial History of The Springfield Armory, 1794-1968, Michael S. Raber, Patrick M. Malone, Robert B. Gordon, Carolyn C. Cooper (Raber Associates, South Glastonbury, CT 06073), edited by Richard Colton, 2008, Ch. 7, p. 214.