I just received a Gweike roller style rotary from Automation Technology. I picked that one because I will be doing mostly cutting on open cylinders so I thought it would be more suitable than the the kind with a chuck and cone. From just plugging it in a running it a little, I'm not sure it will work. It is easy for the workpiece to jump off of the roller, though I think I can help that by making a jig to fit inside and increase the weight. However I am also noticing a tendency for the piece to slide left and right as it turns. Is there anything I can do to insure the piece stays in position? Since I am not rastering, it will be moving back and forth a fair amount rather advancing 1 line at a time in one direction.