Abstract: A metal cutting tool is disclosed which includes a cylindrical cutting body (12) having an outer cylindrical surface (13) approximating the size of the hole desired and an inner wall (14) which tapers towards a base (15). The cutter body further includes a notch (17) for removal of cutting chips which has a socket disposed on the leading edge thereof. A carbide cutting tip (26) is disposed in the socket with the cutting tip being substantially pyramidically shaped, having a blunt cutting edge (35) extending above the cutter body. The metal cutting tool further includes a pilot bit (36) extending axially through the center of the cutter body, with the pilot including a short fluted (37) section which extends above the top of the cutting tip and provides a pilot hole for guiding the cutting tip during hole cutting.

Abstract: Hole punch apparatus comprises a worm and worm wheel whereby an ordinary electric drill can be employed to punch holes in sheet metal by means of a punch and die. The several disclosed structures variously comprise a shear pin for preventing overload, a handle for rapid engagement of the punch and die with the workpiece, bushings to protect against unusual torques, and special threads.

Abstract: A drill bit for drilling holes of a given diameter in wood or similar material comprising a drill body having a series of stepped cylindrical portions increasing in diameter from the small entry end of the drill to the full diameter of the hole to be drilled whereby the drill body is of generally conical shape. Each of the cylindrical portions extends in a helical direction, and a single flute extends generally lengthwise of the drill body to provide cutting edges for the cylindrical portions and a discharge path for material cut from the workpiece. The flute extends generally parallel to the axis of the drill and forms approximately a right angle in transverse cross section, occupying approximately one fourth of the cross sectional area of the drill body. A male thread extends helically along each of the cylindrical portions excepting the largest full diameter portion and projects radially outwardly from each of such portions to engage the walls of the workpiece and thus feed the drill through the workpiece.