Adjusting device for a rotary tool

An adjusting device for a rotary tool for the machining treatment of bores, in particular a short clamping holder having radially finely adjustable standard cutting plates comprising a holder which has at least one receptacle for a cutting plate and a hole for passage of a fastening screw for fixing on a carrier wherein on its part carrying the cutting plate, the holder can be deflected elastically relative to a support by means of an adjusting device designed as a setscrew, with a pressure zone on a threadless circumferential part jointly with a complementary zone on the holder forming a wedge surface pair, which is connected to the base part by means of a threaded pin and which is provided with a scale, the holder is provided with a break and forms a parallel-flexible spring arrangement so that the cutting plate substantially experiences a radial displacement in relation to the cutting edge during its adjustment, characterized in that the annular or plate-shaped scale (21) applied to the head of the setscrew (8) has 25 to 60 graduation marks and on the base body (12) at least one orientation mark (22) is provided for the scaling, the conical section (23) of the threadless part (15) of the adjusting screw (8) has an angle (α/2) of 4.5 to 24°, the pitch of the threaded pin of the setscrew (8) is 0.1 to 0.3 mm and the radial adjustment range is 0.1 to 5 mm.