Abstract: In a mining machine having a power driven cutter including metallic helical blade means having cutting bit means spaced along the exterior periphery thereof, the improvement which comprises the helical blade means having fixedly secured in surface-to-surface contact therewith energy absorbing layer means for dampening vibrations set up in the metal of the helical blade means when the cutter is in power operated cutting relation so as to materially reduce the operating noise level of the cutter within the mine.

Abstract: This invention provides a drill, drilling apparatus, and methods for their use, in which a plastic shank of uniform external diameter is molded onto one end of an insert made of hard drill material. The end of the insert which is encompassed by plastic has dimensions and configurations designed to prevent axial and rotational slippage of the insert inside the plastic shank when the drill is in use. The unattached end of the insert is provided with a cutting tip and drilling flutes. High speed automatic drilling and drill-changing operations are described in which a number of drills having different flute diameters, but uniform shank diameters, are used consecutively.

Abstract: A rotary cutting tool used successfully for machining metal articles, metallic strips, round bars and pipes including descaling, derusting, grinding and polishing. The tool has an arbor with sets of cutting elements in the form of pieces of wire which are compressed and fixed to one another at one end. Secured to the fixed ends across the width of each set there are strips resting on the arbor and fastened to the latter. The free other ends of the cutting elements form the cutting surface of the tool. This construction of the tool allows its use for machining the surfaces of articles of an unlimited width.

Abstract: A radially adjustable rotary cutting tool such as a rotary reamer or the like. The tool head has a generally cylindrical body with a shank at one end and a radially slotted cutting head at the other end. The cutting head has a central axially extending threaded bore adapted to receive a threaded expansion element that may be used to radially expand or enlarge the cutting head when turned into the bore. The cutting head has an inner core portion formed of a low to medium alloy carbon steel and an annular outer portion formed of a tool steel metallurgically bonded to the core portion to provide a unitary composite structure. The annular outer portion has a plurality of circumferentially spaced longitudinal flutes formed therein to define integral longitudinally extending radially adjustable cutting surfaces.