i can file the fucker down if neccesary
DONT, if you file it you disrupt the smooth exterior of the bar, and file to far to metal and oh oh.... slowly put it into the rbf and see if it spins with water in there, just make sure it does not bang around with water, if the bar hits al foil in the mix it can spin slightly off its axis and hit the rbf wall a bit harder....
mine does flip around a fair bit in there until most of the al foil is used up but the one i use is 25mm long.
-AC