That looks pretty similar to my saw blade attempt. Even down to the magic marker lines on the rusty blades. If you can find bearings with a center hole to match the threaded rod, then you can rig it with a bearing pretty easily. With your setup you can rig a bearing by drawing its circumfrence centered on the saw blade and on a washer with a hole in the center larger than the nuts that you are using on your threaded rod axle. Mark and drill 4 small bolt holes at 90 degree angles on the washer and the saw blade so that the entire circumfirence of the bolt is just outside of the circle for the bearing. Do the same thing for the washer. slide the 4 small bolts through the holes in the saw blade. The bearing should fit snuggly between them. then slide the washer over the top and fasten the nuts on the 4 small bolts with lock washers. Now if everything lined up properly, you can slide the whole contraption over the threaded rod, and secure its position on the rod by placing a nut, locking washer, and another nut on each side of the saw blades position and snugging it up. The nuts should tighten against the inside ring of the bearing and the center holes in the saw blade and the washer have to be large enough to spin freely around the nut, but small enough to catch the metal outer ring of the bearing. Rich