I need to make two close fitting cylinders that are longitudinally locked in position but need to rotate against each other. I want to make this in as few parts as possible. I was thinking of machining grooves in each cylinder and placing the Teflon ring in the groove of the inner cylinder and pressing the outer cylinder on. How secure would this arrangement be? Are there any other alternatives? Is Teflon the ideal material for the ring? Thanks in advance for any help.