A screw-threaded working cylinder, comprising a tubular cylinder , a closure and a piston unit , wherein the tubular cylinder has an end region , wherein the tubular cylinder has a first thread in the end region and wherein the piston unit is accommodated in the tubular cylinder , wherein the closure has a second thread , and wherein the closure is screwed by the second thread with the first thread of the tubular cylinder in a final mounting position, wherein the end region of the tubular cylinder has a tapered wall section , wherein the tapered wall section is arranged in an axially distal position with respect to the first thread and has a reduced wall thickness compared to the other regions of the tubular cylinder , wherein the reduced wall thickness is between 20% and 60% of the wall thickness of the tubular cylinder and a length of the tapered wall section is at least one times the wall thickness of the tapered wall section , wherein the tapered wall section has an axial annular surface and wherein the closure has a mating axial annular surface and wherein the axial annular surface and the mating axial annular surface are pressed in a positive fitting contact to each other in the final mounting position and form a pressure contact surface , wherein the pressure contact surface forms a sealing plane, wherein a surface pressure in the area of the pressure contact surface causes a deformation of the tubular cylinder and the closure , wherein the screw-threaded working cylinder is adjusted such that deformation occurs both without and with pressure application by a pressure medium within an elastic limit. comprising a tubular cylinder , a closure and a piston unit , wherein the tubular cylinder has an end region , wherein the tubular cylinder has a first thread in the end region and wherein the piston unit is accommodated in the tubular cylinder , wherein the closure has a second thread , and wherein the closure is screwed by the second thread with the first thread of the tubular cylinder in a final mounting position, wherein the end region of the tubular cylinder has a tapered wall section , wherein the tapered wall section is arranged in an axially distal position with respect to the first thread and has a reduced wall thickness compared to the other regions of the tubular cylinder , wherein the reduced wall thickness is between 20% and 60% of the wall thickness of the tubular cylinder and a length of the tapered wall section is at least one times the wall thickness of the tapered wall section , wherein the tapered wall section has an axial annular surface and wherein the closure has a mating axial annular surface and wherein the axial annular surface and the mating axial annular surface are pressed in a positive fitting contact to each other in the final mounting position and form a pressure contact surface , wherein the pressure contact surface forms a sealing plane, wherein a surface pressure in the area of the pressure contact surface causes a deformation of the tubular cylinder and the closure , wherein the screw-threaded working cylinder is adjusted such that deformation occurs both without and with pressure application by a pressure medium within an elastic limit. <EOS>