Abstract: There is described a device for mounting and removing a cutter at the end of the cutter shaft from a hydraulic or suction dredge, whereby the cutter boss is provided with an inner screw-thread and the cutter shaft with an outer screw-thread. The device is comprised of two concentric rings those surfaces of which facing one another are provided with teeth fitting into one another, whereby the slanting of said teeth is opposite to the angle of said screw-threads, and means are provided to lock both rings during the screwing of the cutter on the shaft thereof, in such a position relative to one another where said rings have so rotated relative to one another that the joint thickness thereof is increased as compared with the joint thickness of the toothed rings when the teeth have completely rotated into one another.