A one or two-piece rotary drill includes a steel shank adapted to fit into
a chuck of an electric drill, a drill bit and a frusto conical or frusto
spherical file between the shank and the drill bit and all of which are
disposed on a common longitudinal axis. The frusto conical or frusto
spherical file includes a plurality of crowned teeth about its periphery
and wherein each of the teeth have a front cutting side and a back side
which includes a plurality of sharp serrations thereon. The composition
of the steel tool includes carbon, silicon, molybdenum and chrome. A
rotary tool set including a plurality of drill bits and file portions
having a plurality of shapes is also disclosed.