Keystone Lock was formed in 1879 by E.T. Fraim and brothers and grew to be a major manufacturing operation in Lancaster, claiming to be the largest manufacturer of locks under one roof in the world. After his death in 1917, E.T. Fraim's son Samuel assumed ownership of the business. In 1925, his other son William purchased an interest in Slaymaker Lock, forming the Fraim-Slaymaker Lock Company. Keystone Lock Company was acquired by Safe Hardware and Lock Company in 1955. source: Locks and Lockmakers of America (Hennessey).