Ask a random group of people to explain Rotabroach annular cutting, and you’ll probably get silence. Pose the same question to workers at Lum, MI-based Lumco Manufacturing Co. and you’ll get an earful. The reason: They often make machines that use this technology to cut ferrous and nonferrous metals.
Invented by Dr. E. Douglas Hougen in the early 1970s, the Rotabroach annular cutter is a hollow, multiple-edge tool that cuts only an annular groove at the periphery of a hole, leaving a solid core or slug at the hole center. The cutter creates cylindrical holes in a circular cross section faster, easier, and more accurately and cost-effectively than conventional twist drills or drill bits.