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.