Abstract: A cutter for a tunnel boring machine with cutter ring in two or more ring segments with a dovetail base, clamped to the cutter hub by a segmented clamping ring. The ring segments have a wedge shaped cross section, and are mounted in a groove. The segments are fastened to the hub by bolts. To facilitate loosening of the ring segments, the segments have a curvature different from that of the groove, so that an elastic force will be accumulated in the ring segments when they are mounted and the bolts are tightened. The curvature of the ring segments is either smaller or greater than that of the groove.