A mechanical device includes a female component having a right-circular cylindrical internal surface and a cylindrical axis, and a first helical recess in the internal surface of the female component. A male component having a right-circular cylindrical external surface is sized to be slidably received within the right-circular cylindrical internal surface of the female component and has a second helical recess in its external surface. The second helical recess has a helical pitch which is the same as that of the first helical recess, so that the second helical recess is in facing relationship along its length to the first helical recess when the male component is assembled to the female component. A retainer is received within the first helical recess and the facing second helical recess when the male component is assembled to the female component. The retainer has an organic plastic retainer outer surface, preferably a polytetrafluoroethylene retainer outer surface.