This was built by a deceased friend yrs ago and his girlfriend gave it to me. It had a 12v engine cooling fan on it the blades didn't have enough pitch to catch any wind. I got this flex fan out of a wreck and welded a piece of 5/8" all thread to some 5/8"cold rolled to fit the brg cartridges. Hole sawed a 1 1/2" hole thru the 3/16" flat and reamed it with the die grinder so the outer race would just fit and then tapered it to fit the spherical shape of the outer race. Then hole sawed a 1 1/4" hole thru the 10ga to make a brg retainer. Welded the two brg assemblys to the tower and it turned out pretty good for a guy with no lathe or milling machine.