Hamilton Calibers

Hamilton Watch Company was founded in 1892 in Lancaster, Pennsylvania, inheriting the machinery and workforce of the earlier Adams & Perry Watch Company (est. 1874). Hamilton rapidly established itself as a premier American manufacturer, winning government contracts for railroad-grade pocket watches and earning the motto «Watch of Railroad Accuracy.» Its pocket watches were required equipment on many U.S. railroads, and Hamilton supplied the U.S. military with field watches through both World Wars.

In 1969 Hamilton shifted movement production to the Buren factory in Biel, Switzerland, and that same year co-developed the Caliber 11 Chronomatic — the world's first automatic chronograph — in consortium with Heuer, Breitling, and Buren. In 1972, Hamilton introduced the world's first digital wristwatch, the Pulsar. The brand was acquired by SSIH (later the Swatch Group) in 1974 and continues today as a Swiss-made brand that retains its American military and rail heritage. Collectors prize Hamilton's railroad-grade pocket watches (e.g., the 992B and 950B) and its mid-century American-made wristwatches.