I made the mistake of turning the Dual Action Polisher Pro on without putting the backing plate and polishing pad on the machine , it was to so powerful I called the Shurhold Tech. Dept. and talked with him about returning the machine & returning the machine. He then explained that without putting the backing plate & pad on you would get that type of vibration and power. I took his advice and am now extremely happy with the machine . This is my first experience with a quality buffing machine .