Readjustment System

A readjustment system comprising an advancing head supporting at least one cutting edge and being retained on a spindle in which an actuation element adjustable approximately in the axial direction by an actuating drive is guided, the actuation element being operatively connected to the advancing head for radial adjustment of the cutting edge, characterized in that the actuating drive is a linear drive, wherein the spindle is configured to include an integrated direct drive arranged coaxially with respect to the spindle axle, and a measuring system is provided for detecting a stroke of the actuation element, wherein the measuring system is a magnetostrictive measuring system comprising a waveguide which is supported in the actuation element and on which a permanent annular magnet is arranged, wherein a converter member is retained on a rear side of the spindle.