I have a cue with a standard 5 16-14 joint pin like a Schon and its weird the shaft will loosen by itself after a few shots and noticed it the first time when I was chalking on a angle and the somehow maybe the vibration from chalking contributed to it loosening.Anyone have a clue why the shaft would loosen or the remedy to fix it.The joint is stainless steel.Thanks in advance for anyone's help.