How To Drill Square Holes

upper.us.edu — A bit that drills square holes ... it defies common sense. How can a revolving edge cut anything but a circular hole? Not only do such bits exist (as well as bits for pentagonal, hexagonal and octagonal holes), but they derive their shape from a simple geometric construction known as a Reuleaux triangle (after Franz Reuleaux, 1829-1905). Nov 30, 2006 View in Crawl 4