Pics & related @
formatting link
Works like a champ, you can use both the platen and contact wheel w/o swapping anything, belt tension and tracking are adjustable.
HF buffer: $50 (or 0 if you have a sufficiently power grinder/buffer already) , assorted HW: $60 (less if you got a junk yard nearby and/or some alum/HRS in junk box).
Please note that first few pics I didn't rotate as I should've - so use your favorite viewer to do that: 90 CW. Or tilt your head.