I made one that mounts through a workbench table top using a blade spindle from a riding lawnmower, a belt, 1/2hp motor from a washing machine, a 1" pulley for the motor drive shaft, a couple of stainless steel mixing bowls nested together for strength, a very large door hinge, a appliance leveling foot, a couple pieces of scrap angle iron, and a scrap piece of 1/4"x6"x10" plate aluminum, various nuts, bolts, and washers. As you can see it takes a few parts, I was lucky the only things I had to purchase were the bowls(Target), the blade spindle(used at a lawnmower repair shop for 15.00), the pulley(tractor supply), the belt(tractor supply), all the rest I had laying around my shop. I would suggest buying one if you don't have all this kind of stuff laying around (it would probably be cheaper) and if you have to ask how to make one to begin with (no offense intended), because you need just a little bit of mechanical know-how and shop tools ect. to pull all this off.
--------------------
----------------------------------------
Patrick