Abstract: A drill steel and a drill bit having a tip with a cutting element and a hollow open ended shank forming a polygonal socket which is fitted onto a complementary engagement portion at one end of the drill steel so that rotation of the drill steel rotates the bit. The engagement portion of the drill steel has an axial slot to hold a spring retainer clip with a protrusion. A slot is formed in the shank of the drill bit to receive the protrusion on the spring retainer clip to hold the bit in the axial position on the drill steel. An opening in the shank of the drill bit and a pin extending through the opening and through the axial slot in the engagement portion of the drill steel when a spring retainer clip is not located in the slot.

Abstract: A drill bit having a hollow shank, a cutting element and a mounting bridge supported in diametrically opposed cutouts at one end of the shank. The bridge is U-shaped in cross section with a base and spaced parallel legs perpendicular to the base. The cutting element is mounted in the bridge with the inner surfaces of the parallel legs of the bridge embracing a portion of each face of the cutting element and the bottom edge of the cutting element resting on the base of the bridge to support the cutting element against shear forces and against compression forces. The edge of the shank which supports the bridge is uneven throughout each 180.degree. of its periphery on both sides of the diametrically opposed cutouts.