In known cutter assemblies, a cutter bit is dragged through a formation, thereby producing an unbalanced moment on the cutter bit which causes it to rotate. However, cuttings can lodge between the cutter bit and the holder, resulting in a frictional force greater than the unbalanced moment tending to...http://www.google.com/patents/US3945681?utm_source=gb-gplus-sharePatent US3945681 - Cutter assembly
