aug, i tthink he is talkign about the center shaft peice.
dude, as long as it works, and works properly then no worries.
and remember this, the more you screw with something that is loose the worse it will get, so if you sit and turn the knob back and forth conplaining about how much it "wobbles" then its not really solving anything.
i say as long as it still works properly, then no worries.
but just in case, try what aug said.