Abstract: A drill bit blade for masonry and rock drills incudes first and second lateral side surfaces, first and second flank side surfaces, and converging first and second tip face surfaces. A first lateral cutting edge is defined by the intersection of the first tip face surface with the first lateral side surface, and a first lateral trailing edge is defined by the intersection of the first tip face surface with the second lateral side surface. A first lateral cutting edge is defined by the intersection of the first tip face surface with the second lateral side surface, and a second lateral trailing edge is defined by the intersection of the second tip face surface with the first lateral side surface. A chisel edge is defined at the converging intersection of the first and second tip face surfaces.

Abstract: A mining drill having a generally cylindrical, hollow bit holder and a cutting bit attached to the holder. The holder has a diametrically located web and two side wall surfaces projecting from opposite longitudinal sides of the web. A pair of cutting bit locating inclined surfaces are located on the web, each one of the inclined surfaces slanting toward a different one of the two wall surfaces. The cutting bit is sized and configures to be received in the space between the wall surfaces and has a flat bottom surface which rests on the web. The cutting bit is formed with two beveled notches, each notch receiving a different one of the inclined surfaces located on the web for locating the cutting bit in a predetermined relationship to the two side wall surfaces. The cutting bit is attached to the bit holder by solder between the cutting bit and side wall surfaces of the bit holder.