Stop 81 of 109 · Swap the Parts
1854 · Waltham, Massachusetts
The Factory Where Every Part Fit Every Watch
An American factory on the Charles River proved that watch parts could be machined precisely enough to be interchangeable, and alarmed Switzerland's watchmakers.
Before the 1850s, a watch was essentially a one-off. Each part was hand-filed to fit its own particular movement, so a broken gear from one watch was useless in another, even one from the same maker.
The company that became the Waltham Watch Company, moving its factory to the Charles River in Massachusetts in 1854, did something different: it built machines that cut parts to a master gauge, and checked every piece against that gauge before it went into a watch. A wheel made in January would fit a watch assembled in June, and either could be repaired with a spare part rather than a new hand-fitted one.
Full interchangeability took decades longer to perfect than the factory's early advertising suggested, but the direction was clear enough to worry Switzerland's watchmakers. After the 1876 Philadelphia exhibition, where Waltham showed off its automatic screw-making machinery, the Swiss engineer Jacques David toured American factories and wrote a long, alarmed report warning that mechanized production was a real threat to Swiss watchmaking, and urging it to adopt the same methods.
It did, eventually, and interchangeable parts became the industry norm rather than an American curiosity. Every watch factory since, Swiss included, still makes its components to a master size, only measured with far greater precision than Waltham's original gauges allowed.