Adjusting device for drill-bit carriers

The invention relates to an adjusting device for drill-bit carriers in reboring tools for metalworking, for adjusting the drill-bit cutting edge to a specific working diameter. The aim of the invention is to develop an adjusting device, in which the components for securing the set screw axially in position allow an essentially play-free axial support of the set screw in both setting directions for the purpose of improving the adjustment operation. The object on which the invention is based is to improve the axial support of the set screw on an inner retaining ring. This object is achieved, according to the invention, in that the inner circumferential groove receiving the inner retaining ring in the guide bore of the basic body has a conical groove flank and a straight groove flank and, in relation to the spread-open inner retaining ring, a smaller annular cross-sectional diameter, with the result that the inserted inner retaining ring is laid with expanding tension against the straight groove flank of the inner circumferential groove in a manner free of play.