Watts Brothers Tool Works is a tool manufacturer located in Wilmerding, Pennsylvania. They are known for manufacturing drill bits, that can drill square holes, including blind holes which cannot be made with other methods such as broaching. The Harry Watts square drill bit is based on a Reuleaux triangle shape, and is used together with a guide and a special chuck to make a square hole. Similarly, the company also manufactures drill bits for other angular holes such as pentagons and hexagons.
- ^ Ragan, Sean Michael (October 6, 2009). "Drilling square holes with a Watts drill". MAKE Magazine. Retrieved February 23, 2016.
- ^ Watts Brothers Tool Works (1950–1951). How to drill square hexagon octagon pentagon holes. New York: Wilmerding, Pa. : The Company,.
- ^ U.S. Patent 1,241,176 Watts, Harry J.: "Drill or Boring Member", applied for November 1, 1916, granted September 25, 1917
- ^ Scott Smith:"Drilling Square Holes", in The Mathematics Teacher, October 1993 (Volume 86 Number 7).