Auger drill bit

摘要

An auger bit (30) for forming bores having a circular cross section in a workpiece is disclosed. The bit has an elongate auger portion (32), a shank, a lead screw (34), a chisel blade (40), a spur blade (36), and a shearing blade (38). The elongate auger portion has an elongate shaft (42) with an elongate helical land (48) formed therein defining a flute between adjacent turns on the elongate helical land. The helical land has a lead edge and following portion. The shank is integrally connected to one end of the elongate auger portion and is adapted to engage a drill. The lead screw is integrally connected to the other end of the elongate auger portion and is for engaging the workpiece. The chisel blade (40) extends outwardly from the leading edge of the elongate helical land and is for chipping material from the workpiece. The spur blade (36) extends longitudinally from the elongate helical land in the direction of the lead screw (34). A cutting edge partially extends longitudinally between the following portion of the elongate helical land proximate to the leading edge and the adjacent helical land. Preferably the cutting edge is a shearing blade (38) which extends longitudinally into the flute between adjacent turns on the elongate helical land. Preferably the shearing blade (38), the chisel blade (40) and the spur blade (36) are removable. Preferably the shearing blade and spur are integrally attached. Alternatively, shearing blade, spur and chisel blade may be integrally attached to form a removable and replaceable multipurpose blade.