ORIGINAL: Geardaddys
that's good to hear... You can drive yourself nuts trying to get a spinner in "perfect" balance on one of those magnetic balancers.. I got it to the point that it would rotate on it's own VERY slowly.. started off falling to the heavy side quickly.. Finally said "well, this is gonna have to be good enough!"!
That's about right.
Even the metal prop/spinner retainers have a tendancy of shifting slightly each time you re-insert the spinner or you rotate them.
This lateral shift will throw off your attempts at balancing the spinner. It is not as dramatic with props which have a longer effective lever moment.
Check the spinner balance, then without removing it, rotate the metal retainer and check again. Frequently you'll find that the balance will shift this way.