I didn't own a small ROS sander and read this was the best of the bunch. I set it up with the vac attached and a fresh sanding disk and handed it to her to start sanding. It seemed to work well but the disk didn't rotate, just seemed to vibrate. My 6" Bosch rotates while it vibrates randomly so I'm not sure if the thing is working properly or not. Can anyone tell me if it's working correctly or not?