A drilling tool, in particular a reamer, for drilling out a workpiece core bore to a nominal diameter by means of a main blade formed on a drill body is disclosed. The main blade has a radially external cutting edge which extends along a drill-body longitudinal axis as far as a blade corner arranged at the drill tip, wherein during the drilling-out operation, the drilling tool is drivable into the workpiece core bore with a rotary movement and a feed movement. The drilling tool has at least one groove blade which is arranged so as to precede the blade corner of the main blade in the direction of rotation of the tool. During the drilling-out operation, the groove blade produces a groove in the inner wall of the core bore drilling, the blade corner of the main blade being guided in the groove with an at least reduced cutting load.

A drilling tool, in particular a reamer, for drilling out a workpiece core bore to a nominal diameter by means of a main blade formed on a drill body is disclosed. The main blade has a radially external cutting edge which extends along a drill-body longitudinal axis as far as a blade corner arranged at the drill tip, wherein during the drilling-out operation, the drilling tool is drivable into the workpiece core bore with a rotary movement and a feed movement. The drilling tool has at least one groove blade which is arranged so as to precede the blade corner of the main blade in the direction of rotation of the tool. During the drilling-out operation, the groove blade produces a groove in the inner wall of the core bore drilling, the blade corner of the main blade being guided in the groove with an at least reduced cutting load.

A boring tool includes a clamping shaft and a boring body. Between the end face of the boring body and the clamping shaft, at least one main blade extends along a longitudinal axis of the boring body and includes a blade web with a rake face facing a groove-shaped chip space, and a free surface on the outer circumferential side, these converging at a cutting edge which runs along the boring body longitudinal axis and which removes material on an inner wall of a pre-bored workpiece core bore hole as a result of said boring tool being rotated. The main blade extending along the longitudinal axis of the boring body transitions at the end face, of the boring body into a groove blade that is aligned transversely to the longitudinal axis of the boring body. This groove blade allows the boring tool to be displaced, prior to removing the material by rotation, into the core bore hole in an axial lifting motion such that a groove is formed which extends along the longitudinal axis of the core bore hole, the main blade of the boring tool engaging in this groove.