I had a problem with Rose.  The end button started to rub my neck, just felt odd.  I tried changing the shoulder rest which worked for a while, but then the button would again punch my neck.  I finally looked and saw that the button was tilted up and working itself out of its hole. Which was also the reason that I had to re-tune it so often. I took it apart, cleaned up the hole, packed some sawdust and glue in, used three sizes of drill bits and a file to re-create the cone shape and put it back together.  It worked.  Then suddenly it all came apart as the tailpiece strap stripped its threads and slammed down.  I put on a new strap and all is well now.  I am assuming that the strap was being stripped one thread at a time which caused the button to tilt as the pressure was released and regained.  As I have been changing strings often and doing other adjustments, I probably have aggravated the situation. 

edit:hmm, guess I was wrong.  Had to retune this morning.  My button is getting loose again.  Blah.