Combination tool as well as drills for such a drilling/chamfering tool

A combination tool comprising a drill extending in a longitudinal direction along a rotational axis (R) and further comprising a clamping sleeve having a cylindrical receptacle, designed to receive the drill and fasten the drill and having a holding seat for a cutting insert, wherein the drill has a cutting region provided with a first groove and a second groove that each extend helically at a twist angle (γ), wherein a first drill back is formed between the first and second grooves and extends helically with a curved peripheral surface, wherein the first drill back is partially flattened to form an adjustment surface that extends helically,

• wherein the drill and the clamping sleeve are forcibly guided together by a guide groove formed on a curved peripheral surface of a second drill back, the guide groove cooperating with the clamping sleeve so that movement of the clamping sleeve in the longitudinal direction causes the clamping sleeve to automatically rotate about the rotational axis (R) in accordance with the twist angle (γ) of the first and second grooves.