also, something you mentioned in an earlier post about proper setup shouldn't vibrate, ANYTHING that rotates, vibrates. even turbines have vibration, just MUCH less than conventional power plants. also, anything that has a rotating airfoil (prop, rotor, whatever) will have a certain amount of vibration. you can reduce the vibration only to a certain point, after that, you can only grin and bear it.

now i have had a vibration in my skids before and found it to be that my blades were too tight in my grips and they were also slightly miss aligned. my fix was that i loosened the grips just a bit so that the blades (under full throttle) whould be pulled straight out by the centrifugal force and i would lose the vibration. just keep in mind that if you use this method, the grip bolts still have to be tight enough that the blades wont fold freely while static. it should still take a lil bit of force to fold them back.