Abstract: A drill head insert or drill head attachment, in particular a drill plate made of hard metal, for a rock drill, includes cutting edges (20, 20a) configured on the feed side which extend from a tip of the drill (18) rearward in a receding manner to an outer face (12, 14) of the drill plate (10). A drill plate (10) is substantially configured in the form of a roof when viewed from the side. A free face (24, 24a) at the cutting edge (20, 20a) abuts against a cutting face (22, 22a) along a substantial part of its extension between the tip of the drill (18) and the outer face (12, 14). A substantially smooth contour of the cutting edge (20, 20a) is interrupted by at least one projection (30, 30a, 30b) which projects beyond the cutting edge (20, 20a) in the feed direction.

Abstract: A drill with a drill flute (12) includes symmetrical fluted lands (20) helically extend around a core, wherein grooves (18) remain between the fluted lands, said grooves having a width (72) that exceeds the spine thickness or width (24) of the fluted lands (20), and wherein the grooves (18) comprise a convex core reinforcement (22) at the groove bottom thereof. The width (24) of the fluted lands (20) at the drill head side end (16) is smaller than at the shank side end (14) of the drill helix (12), and at least increases in certain areas. The core reinforcement (22) at the drill head side end (16) is more convex than at the shank side end (14), thus has larger radii (40, 42).

Abstract: A drill head insert or drill head attachment, in particular a drill plate made of hard metal, for a rock drill, includes cutting edges (20, 20a) configured on the feed side which extend from a tip of the drill (18) rearward in a receding manner to an outer face (12, 14) of the drill plate (10). A drill plate (10) is substantially configured in the form of a roof when viewed from the side. A free face (24, 24a) at the cutting edge (20, 20a) abuts against a cutting face (22, 22a) along a substantial part of its extension between the tip of the drill (18) and the outer face (12, 14). A substantially smooth contour of the cutting edge (20, 20a) is interrupted by at least one projection (30, 30a, 30b) which projects beyond the cutting edge (20, 20a) in the feed direction.

Abstract: A drill with a drill flute (12) includes symmetrical fluted lands (20) helically extend around a core, wherein grooves (18) remain between the fluted lands, said grooves having a width (72) that exceeds the spine thickness or width (24) of the fluted lands (20), and wherein the grooves (18) comprise a convex core reinforcement (22) at the groove bottom thereof. The width (24) of the fluted lands (20) at the drill head side end (16) is smaller than at the shank side end (14) of the drill helix (12), and at least increases in certain areas. The core reinforcement (22) at the drill head side end (16) is more convex than at the shank side end (14), thus has larger radii (40, 42).

Abstract: The invention relates to a drilling tool having a large drill, in particular a core drill, in which a center drill is guided in an axially flexible or movable manner, with the axial movement of said center drill relative to said large drill being limited by at least one limit stop, wherein at least one pin that is supported on the large drill, the shaft thereof or a transition therebetween, extends toward the center drill, and the pin (24) is formed at an attachment body (26) comprising a contact surface (46) that abuts on a counter contact surface (52) of the drilling tool (10) and in particular has at least partially a larger lateral extension than the pin.

Abstract: The invention relates to a drilling tool having a large drill, in particular a core drill, in which a center drill is guided in an axially flexible or movable manner, with the axial movement of said center drill relative to said large drill being limited by at least one limit stop, wherein at least one pin that is supported on the large drill, the shaft thereof or a transition therebetween, extends toward the center drill, and the pin (24) is formed at an attachment body (26) comprising a contact surface (46) that abuts on a counter contact surface (52) of the drilling tool (10) and in particular has at least partially a larger lateral extension than the pin.