Interchangeability of parts was achieved by combining a number of innovations and improvements in machining operations and the invention of several machine tools, such as the slide rest lathe, screw-cutting lathe, turret lathe, milling machine and metal planer. Additional innovations included jigs for guiding the machine tools, fixtures for holding the work piece in the proper position, and blocks and gauges to check the accuracy of the finished parts.
Electrification allowed individual machine tools to be powered by electric motors, eliminating line shaft drives from steam engines or water power and allowing higher speeds, making modern large scale manufacturing possible.
Modern machine tools often have numerical control (NC) which evolved into CNC (computerized numeric control) when microprocessors became available.
Some Examples