I made some funny skate kinda things using all thread, nuts, alternator (used) bearings. One of the nuts was welded to a piece of angle iron. The bearing pinched between the nut with the angle iron and a nut on the out side. Two of these set ups on one piece of all thread which become adjustable in and out so the base of the machine sits between. The bearings become the wheels. Then another of this set up at the other end of the machine. The machine is only lifted about 1.5 inches off the floor. The set up is very forgiving of uneven floors, and roughness. You can just kinda pry the machine along, if the floor is smooth, it will roll easily. If disaster strikes and a set up slips out machine only drops about an inch, no big deal. I've told my self that some day I would start a thread with pictures...........
Tim