Abstract: A grader blade has a steel body with a bottom edge incorporating a pair of tiered, elongated carbide inserts in a forward portion thereof. The carbide inserts, being arranged in a tiered contacting relationship, are disposed in a stepped recess formed in and along the forward portion of the bottom edge of the blade body and brazed to the blade body and to each other so as to project forwardly and downwardly from the recess. A front one of the tiered inserts is composed of a cemented carbide composition having a high cobalt content, for instance 20 percent by weight, adapting it for enhanced impact wear resistance, whereas a rear one of the tiered inserts is composed of a cemented carbide composition having a low cobalt content, for instance 11.5 percent by weight, adapting it for enhanced downpressure wear resistance.

Abstract: An insert, especially a hard wear resistant insert, such as an insert of cemented hard metal carbide, for use in a mining tool or the like. The insert is especially adapted for being press fitted into the body of a mining tool or the like but may also be brazed or cemented therein. The insert has a rounded outer end and a flat inner end and tapers inwardly immediately adjacent the flat inner end and is rounded at the periphery of the flat inner end thereby eliminating stress risers in the insert and providing for easier insertion thereof into a bore in a tool body into which the insert is seated.

Abstract: A percussion bit for use with a down-the-hole drilling motor having a hammer which reciprocates in the motor to impact on the upper end of the bit. The bit has a working position in the motor and an idle advanced position. When the bit is in the idle advanced position, the hammer advances to an idle position and, at that time, it is desired for the hammer merely to rest on the bit without impacting the bit. The hammer is reciprocated by fluid pressure and, according to the present invention, a bypass channel is formed directly in the bit which exhausts one of the pressure chambers for the hammer when the bit is in its advanced position.

Abstract: A mining bit, especially an impact bit for down-the-hole operations and the like, in which the bit comprises a body adapted for being chucked in an impact motor for being impacted by the hammer of the motor and for being rotated by the motor. The working end of the bit includes a detachable cup-shaped cap in which hard wear resistant inserts are mounted.

Abstract: An insert, especially a hard wear resistant insert, such as an insert of cemented hard metal carbide, for use in a mining tool or the like. The insert is especially adapted for being press fitted into the body of a mining tool or the like but may also be brazed or cemented therein. The insert has a rounded outer end and a flat inner end and tapers inwardly immediately adjacent the flat inner end and is rounded at the periphery of the flat inner end thereby eliminating stress risers in the insert and providing for easier insertion thereof into a bore in a tool body into which the insert is seated.

Abstract: An excavation tool, specifically, a down-the-hole bit which reduces a formation by being impacted axially against a formation while rotating and through which a supply of fluid, such as air, is supplied through a passage in the bit to the working face thereof to blow away the material taken by the bit and wherein the working face of the bit is provided with grooves extending outwardly from the lower end of the fluid supply passage to the periphery of the bit and in communication with axial grooves formed in the bit. The provision of the grooves in the working end of the bit in communication with the axial grooves in the outer periphery of the bit greatly improves the removal of debris which accumulates at the bottom of the hole being drilled and increases the efficiency of the bit.

Abstract: A down-the-hole hammer of the type adapted for receiving a bit at the lower end and for being connected to the lower end of a drill string through which compressed air is supplied to the hammer. The supply of air to the hammer when the bit at the lower end is resting on the bottom of the hole causes a piston in the hammer to reciprocate and to beat upon the upper end of the bit so that the material at the bottom of a hole is reduced. The piston, by reciprocating in the hammer, accomplishes the valving of the fluid which causes the piston to reciprocate, and when the hammer is lifted from the bottom of the hole and the bit moves downwardly, the piston ceases reciprocation while air blows off through the bit to the bottom thereof to clear debris from the hole being drilled.