A system is described for positioning and locking in place a nozzle within a cylindrical bore of a body, and a method for positioning and locking in place a nozzle within a cylindrical bore of a body is also described. The system has a nozzle having a tubular shape extending between a first end and a second end with an outer cylindrical surface and an inner surface, said inner surface comprising a thread. The system also has a locking member provided within said nozzle and comprising an outer circumferential surface having a thread that corresponds to the thread of the inner surface of the nozzle. The system also has means for providing torque to said locking member to screw said locking member into and within said nozzle via said threaded surfaces to thereby create a press-fit between said outer cylindrical surface and an inner surface of said cylindrical bore.