Thanks Carol
PhilaGardener, It doesn't take much in the way of tools. You do need a small welder, and some way to cut metal, people cut steel with a cutting wheel on a saw a die grinder. If you want to build this or something like it, that would be an excuse to buy a couple inexpensive tools. You can grind, drill and cut a metal into any shape you want. If you'd like to make one of these, or anything else, I say do it, It's easy.
If you decide to build one I'll help.
The shaft on the engine is 1 1/8", an 1 1/8" centrifugal clutch cost 3 or $400. I plan to start the engine, then file/sand the shaft down 1/16", that will leave a 1" shaft, a Hilliard centrifugal clutch is under $100, a mill should be fine with that.
Richard