Abstract: A rotary cutting tool has an axially moveable drill pilot supported in the forward end of an arbor. A first set screw connects the arbor to an annular hole cutter. A second set screw connects the arbor to the drill pilot. The drill pilot has an integral collar that engages the inner end of the hole cutter to prevent the drill pilot from being ejected from the arbor in the event that the second set screw is disengaged from the drill pilot.

Abstract: A portable electromagnetic drilling machine which is provided with an enclosed motor power control cord that connects the machine electrical control panel to a machine electric drive motor for a cutting tool spindle. The provision of an enclosed electric motor power control cord eliminates any wrongful or inadvertent lifting of the machine by said cord, and insures the lifting and carrying of the machine will be carried out by a handle on the machine housing.

Abstract: An annular hole cutter including a cylindrical body provided with a plurality of circumferentially spaced apart cutter teeth, including a first group of cutter teeth that have alternate radial inner cutting edges and a second group of cutter teeth that have alternate radial outer cutting edges that are staggered circumferentially rearwardly from the alternate radial inner cutting edges of the first group of cutter teeth. The cutting edges on the cutter teeth of both groups of cutter teeth each have a leading point, and the leading point of the cutting edges on one of said groups of cutter teeth extends downward longitudinally beyond the leading point of the cutting edges on the other of said groups of cutter teeth.

Abstract: An annular hole cutter having a shank and an integral cylindrical body provided with a plurality of axially extended cutting teeth which each has an inner cutting edge and an outer cutting edge. The inner and outer cutting edges are equal in radial width and their inner ends meet in a common leading cutter point. The outer and inner cutting edges on each cutting teeth share a substantially mutual radial face.

Abstract: An arbor for a rotary cutting tool which includes an elongated cylindrical shank that has an axial bore formed therethrough. The upper end of the shank is adapted to be attached to the drive spindle of an electric motor. The arbor shaft is slidably mounted in a carrier sleeve which is rotatable with the arbor shank which is retained against axial movement by a mounting means. An annular cutter is attached to the lower end of the arbor shank and a pilot ejector member is slidably mounted therein. The pilot ejector member is retained in the normal at rest position by a spring which has its upper end mounted in a bore in a piston that is attached to the carrier sleeve. The lower end of the spring engages a plunger member which maintains the pilot ejector member in its initial and other operative positions.