Northern has all the engines/ 2 stage pumps/ mounts/ couplings/ valves/ tanks and cyllinders that you will need. All you would have to do is design it, buy the steel, cut, weld it . If your not planning on building a beast or something custom, your best bet may be to buy new or used. Your cheapest bet to build is a tractor mounted unit, for the money and time invested, its operation may cost you more than say an 8hp self contained unit. Why I say this is because of the earlier $800 20 ton example and after I priced all the steel, wheels, lights, etc for a 2900# trailer I would only save $250. So I bought new because it was cheaper to buy since my labor was worth more than that. /forums/images/graemlins/grin.gif Franz