The Keystone Driller Company was founded on February 2, 1882 by brothers Robert M. and John G. Downie and James D. McAnlis in Fallston, Pennsylvania. It was a successor to R. M. Downie & Bro., which had been established by the Downie brothers in Allegheny City, Pennsylvania in 1879. Its industry was drilling machinery and its headquarters were in Fallston, Pennsylvania (1882-1887) and Beaver Falls, Pennsylvania (1887-1959).
The company filed for bankruptcy in 1937 and was reorganized in 1940. In 1952, the firm acquired and merged with the Star Drilling Machine Company. The plant was shut down in 1959 after being sold to the Koehring Company. Its operations were consolidated with the Buffalo-Springfield Roller Company, a subsidiary of Koehring, in Springfield, Ohio.
- Beaver Falls, Pennsylvania (1887-1959)
- Carthage, Missouri (1896-1917)
- Fallston, Pennsylvania (1882-1891)
- Joplin, Missouri (1917-1951)
Keystone Portable Steam Driller Company (1882-1891)
Keystone Driller Company (1891-1952)
Stardrill-Keystone Company (1952-1959)