Have you actually built one of these things and tested it? If so, why not show pictures of the fully-assembled unit in the ebay ad? It speaks of planetary gearboxes, belts and pulleys, but they aren't shown, nor are the tilt-axis motor and cabling. I can't even figure out how it's supposed to mount to the machine, since there appears to be a motor where the attachment point would normally be. Do you have a video of this unit cutting steel, as the ad claims it can?