Abstract: A frustum cutting insert having a cutting end and a shank end and the cutting end having a cutting edge and inner walls defining a conical tapered surface. First walls in the insert define a cavity at the inner end of the inner walls and second walls define a plurality of apertures extending from the cavity to regions external the cutting insert to define a powder flow passage from regions adjacent the cutting edge, past the inner walls, through the cavity and through the apertures.

Abstract: A rotary spade drill arrangement comprising a combination spade drill body having a rotational axis, a shank portion, and a generally planar spade cutter portion with a pair of oppositely directed cutting edges extending radially of the axis, and a rotatable frusto conical cutter mounted on the spade cutter portion adjacent the maximum radial extent of each cutting edge.

Abstract: A roof bolt bit arrangement comprising a combination spade drill body having a rotational axis, a shank portion, a generally planar spade cutter portion with a pair of oppositely directed cutting edges extending radially of the axis, and at least one rotatable frusto conical cutter mounted on the shank portion with its cutting edge in the path of the maximum radial extent of each spade cutter portion cutting edge.

Abstract: A rotary drill arrangement comprising a combination spade drill body having a rotational axis, a shank portion, and a generally planar spade cutter portion with a pair of oppositely directed cutting edges extending radially of the axis, and a rotatable frusto conical cutter mounted on the spade cutter portion adjacent the maximum radial extent of each cutting edge.

Abstract: An improved cutting insert cartridge arrangement for quick and easy mounting of cutting inserts to and removal from a rotary cutting tool, comprising a cutting insert receiver for the cutting insert, the insert receiver itself being quickly and easily removed from the rotary cutting tool body. The cutting insert receiver may have an outer end portion with an opening therein for receiving a cutting insert, the outer end portion being configurable to apply a varying lateral grasping force against an inserted cutting insert. The cutting insert receiver may be frusto conical in shape to mate with a complementary frusto conical recess in the rotary cutting tool body, whereby securing the receiver in the recess serves to apply the lateral grasping force against an inserted cutting insert due to the camming action between the mating surfaces of the two frusto conical members.

Abstract: A frustum cutting bit arrangement, including a shank portion for mounting in, and to be retained by, a rotary cutting tool body, the shank portion having an axis, an inner axial end, and an outer axial end. A head portion has an axis coincident with the shank portion axis, a front axial end, and a rear axial end, the rear end coupled to the shank portion outer end, and the front end having a conical cavity therein diminishing in diameter from the front end toward the rear end. A frustum cutting insert has an axis coincident with the head portion axis, a forward axial end, a back axial end, and an outer conical surface diminishing in diameter from the forward end toward the back end, the conical cavity and the outer conical surface having substantially the same taper, the frustum cutting insert fitting into the cavity in a taper lock.