By the summer of 1920, 11 men were working in the unfinished factory. They made snap fasteners to hold the side curtains of early, “open” automobiles. In 1928, the Hamilton plant became the United-Carr Fastener Company, after its parent company merged with the United States Fastener Company of Boston, Massachusetts.

The company soon broadened its product line to include fasteners for clothing, automobiles, boats and airplane curtains, as well as radio tube pins, clips and sockets. The plant was dramatically expanded. By the late 1930s, over 150 men and women were working here.

After World War II, the company also began producing precision-made parts, such as pen and pencil components, television connectors and screw shells for electric lights and fuses. In the 1960s, production was transferred to a 75,000-square-foot facility in Stoney Creek.

Like other groups of Hamilton workers, United-Carr employees formed their own credit union. It was one of the few suppliers of credit available to workers at the time.