Watts Brothers Tool Works is a tool manufacturer located in Wilmerding, Pennsylvania.
They are known for manufacturing drill bits that can drill square holes,[1][2] 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.
It is used together with a guide and a particular chuck to make a square hole.
[3][4] Similarly, the company also manufactures drill bits for other angular holes such as pentagons and hexagons.