embodiments of the present invention the set screw 301 may be configured such that the thread on threaded shaft 303 is arranged to be threaded in a different direction than the thread on the threaded bore 307 that is in embodiments where the threaded shaft 303 on the outside of set screw 301 is a left hand thread the threaded bore 307 on the inside of set screw 301 will be arranged to have a right hand thread correspondingly in the above described embodiment the screw 311 is configured to have its own threaded shaft portion 313 which is threaded with a right hand thread and sized to correspond to the threaded bore 307 of the set screw 301 that is the threaded shaft 303 of set screw 301 and the threaded shaft 313 of screw 311 will be arranged in opposite directions referring to fig3 and 5 in addition to the threaded shaft 313 the screw 311 may also include a head portion 315 the head portion 315 may also be substantially cylindrical and have a diameter that is greater than or equal to a diameter of the threaded shaft 313 of screw 311 generally a maximum diameter of screw 311 will be equal to or smaller than a maximum diameter of the set screw 301 the head portion 315 of screw 311.