A method for connecting a plastic workpiece to a further workpiece with the following steps: - providing a plastic workpiece, comprising a first abutting surface, provided on which is a pin projecting away from it and having an end face facing away from the first abutting surface, - providing a further workpiece, comprising a second abutting surface and a working surface opposite from the second abutting surface, a through-opening which is adapted to the cross section of the pin and extends from the second abutting surface to the working surface being provided in the further workpiece, - placing the further workpiece and the plastic workpiece against each other in such a way that the second abutting surface lies on the first abutting surface, the pin extending through the through-opening, beyond the working surface, - placing a friction tool against the further workpiece, the friction tool having a friction pin driven in a rotating manner about an axis of rotation and comprising a friction surface extending perpendicularly in relation to the axis of rotation and having a clamping ring comprising a clamping surface extending perpendicularly in relation to the axis of rotation, the clamping ring surrounding the friction pin and the friction pin and the clamping ring being able to be moved parallel to the axis of rotation, placement involving the friction surface being placed flat on the end face and the clamping surface being placed flat on the working surface, - rotating the friction pin, so that the frictional heat produced by friction between the friction surface and the end face brings the pin into a plasticized state, and - moving the rotating friction pin parallel to the axis of rotation toward the working surface, so that the pin is plastically deformed, wherein the friction tool has an annular sleeve, which is driven in a rotating manner about the axis of rotation, which can be moved parallel to the axis of rotation, and which comprises a sleeve friction surface extending perpendicularly in relation to the axis of rotation, wherein the sleeve is arranged between the friction pin and the clamping ring, wherein the sleeve is rotated when the friction pin rotates, and wherein either a) the sleeve is moved away from the working surface when the friction pin moves toward the working surface, or b) during the moving of the friction pin, the sleeve is also moved parallel to the friction surface toward the working surface. - providing a plastic workpiece, comprising a first abutting surface, provided on which is a pin projecting away from it and having an end face facing away from the first abutting surface, - providing a further workpiece, comprising a second abutting surface and a working surface opposite from the second abutting surface, a through-opening which is adapted to the cross section of the pin and extends from the second abutting surface to the working surface being provided in the further workpiece, - placing the further workpiece and the plastic workpiece against each other in such a way that the second abutting surface lies on the first abutting surface, the pin extending through the through-opening, beyond the working surface, - placing a friction tool against the further workpiece, the friction tool having a friction pin driven in a rotating manner about an axis of rotation and comprising a friction surface extending perpendicularly in relation to the axis of rotation and having a clamping ring comprising a clamping surface extending perpendicularly in relation to the axis of rotation, the clamping ring surrounding the friction pin and the friction pin and the clamping ring being able to be moved parallel to the axis of rotation, placement involving the friction surface being placed flat on the end face and the clamping surface being placed flat on the working surface, - rotating the friction pin, so that the frictional heat produced by friction between the friction surface and the end face brings the pin into a plasticized state, and - moving the rotating friction pin parallel to the axis of rotation toward the working surface, so that the pin is plastically deformed, wherein the friction tool has an annular sleeve, which is driven in a rotating manner about the axis of rotation, which can be moved parallel to the axis of rotation, and which comprises a sleeve friction surface extending perpendicularly in relation to the axis of rotation, wherein the sleeve is arranged between the friction pin and the clamping ring, wherein the sleeve is rotated when the friction pin rotates, and wherein either a) the sleeve is moved away from the working surface when the friction pin moves toward the working surface, or b) during the moving of the friction pin, the sleeve is also moved parallel to the friction surface toward the working surface. a) the sleeve is moved away from the working surface when the friction pin moves toward the working surface, or b) during the moving of the friction pin, the sleeve is also moved parallel to the friction surface toward the working surface.