The other thing I thought I would mention is, in the pictures it looks like there is room for some sort of clamp, but in reality the shaft kind of moves side to side as it goes up & down, so even if its centered the way I have mine in the pictures, it doesn't stay in the middle when its operating. I guess that makes sense too because when you think about it, there nothing to keep the rod centered. just the diaphragm & it is turning inside out as it moves too. Just my thoughts for the day
