Abstract: The invention relates to a dual-cutting drilling tool. The drilling tool comprises a base body (14) which is rotatable about a drill axis (36) and in which two plate seats (16) are arranged on the front face thereof for receiving identically configured alternating cutting plates (16). The alternative cutting plates are respectively provided on a main cutting edge (28) thereof with an adjacent first face (30), forming a cutting wedge, and a free surface (24). The main cutting edges (28) of the alternating cutting plates (20) complement each other in the region of a central, offset cutting part (28?), forming a cross-cutting edge which is interrupted by a center hole (60). The aim of the Invention is to reduce the risk of breakage in the center area of the alternating cutting plates and to provide better guidance for the tool.

Abstract: A solid drill bit for machine tools. has a bit body and two movable inserts located a radial distance apart in insert seats of the bit body. The inserts have a rectangular or quadratic contour, project axially over the bit body with their major cutting edges and overlap in their working area. The outer movable insert projects radially beyond the periphery of the bit body with its outer cutting edge corner and with the adjoining minor cutting edge. Starting from the cutting edge corner, the minor cutting edge is inclined in the direction of the bit body at a setting angle of less than 3.2 °. The minor cutting edge has a guiding edge that is slidingly supported against the wall of the bore over at least part of its length due to a radially outwardly oriented thrust force.

Abstract: The invention relates to a dual-cutting drilling tool. The drilling comprises a base body (14) which is rotatable about a drill axis (36) and in which two plate seats (16) are arranged on the front face thereof for receiving identically configured alternating cutting plates (16). The alternative cutting plates are respectively provided on a main cutting edge (28) thereof with an adjacent first face (30), forming a cutting wedge, and a free surface (24). The main cutting edges (28) of the alternating cutting plates (20) complement each other in the region of a central, offset cutting part (28?), forming a cross-cutting edge which is interrupted by a center hole (60). The aim of the invention is to reduce the risk of breakage in the center area of the alternating cutting plates and to provide better guidance for the tool.

Abstract: The invention relates to a solid drill bit for machine tools. Said first bit has a bit body (10) and two movable inserts (20,22) which are located a radial distance apart, each in an insert seat (16,18) of the bit body (10), in the area of a chip-conveying channel (12,14). The moveable inserts (20,22) have a rectangular or quadratic contour, project axially over the bit body (10) with their front-end main blades (30,34) and overlap each other radially in their working area. The radially outer movable insert (22) projects radially beyond the periphery of the bit body (10) with its outer tool corner (36) and with its adjoining secondary blade (38), which is perpendicular to the corresponding main blade (34). Starting from the tool corner (36), the longitudinal extension of the secondary blade (38) concerned is inclined in the direction of the bit body (10) at a defined setting angle of less than 3.2°.