A shaft, especially a motor shaft, is inserted into an accommodation area of a hub, especially an adapter shaft, and is connected with force locking, especially being clamped. The hub, at least in one axial area, has three flattenings evenly spaced from one another in the circumferential direction. A first threaded part, particularly a first, preferably radially-acting setscrew, is screwed into a clamping ring and presses on one area of the hub in order to bring about the force-locking connection, especially by bracing the clamping ring against the hub, in particular, the area covering an angle-at-circumference area which is smaller than the angular distance in the circumferential direction between two flattenings immediately adjacent in the circumferential direction.