Abstract: A pressure cylinder assembly includes a cylinder and an outwardly projecting flange. The assembly is formed by inserting into the cylinder open end a body having a groove in its outer surface, so that the groove lies in opposition to a wall of the member, and deforming said wall into the groove to lock the body axially within the member. This deformation produces corresponding depressions in the outer surface of the member. A flanged collar is then placed around the member and deformed into the depressions to lock the collar axially and rotationally relative to the body with the flange of the collar projecting outwardly for mounting the assembly on a support.