ArtMetal

Start With D.O.M. (drawn over madrell) tubing. 2.5 inch O.D.x1.25 I.D. Or thereabouts. Cut to length (3"-6"). Put a large chamfer on the inside of each end. (round file, die grinder, or a broken off bit of round file in a drill motor. Chamfer the ends of some 1.25 dia. cold finished steel shaft. Heat one end of tube red, press shaft in a little. If You do not have a press, Hammer it. Here is where a large bevel on the end will prevent damage to the shaft. Weld tube to shaft (fill tube chamfer). One roller needs bearing lenth shafts at each end. One needs room for just a bearing at one end and a bearing and a sprocket at the other end. The third needs bearing, sprocket at one end, Bearing, sprocket,and hub at other end. Gear redution is simple. Make large ring like old steel wagon wheel. 5'-6'dia. Use same size D.O.M. tube for hub of wheel. Bump bend with hammer and vice if you have to. 5' wheel w/2.5" roller gives 24-1 ratio. Use small diameter chain sprockets on other end of the two non-ajustable rollers, Connect with chain(40 picth or what you have) If you can't cut keyways, grind flat spots on shaft. On drive hub, use .5" dia. set screw on flat spot of shaft. Look up pictures of a blacksmiths tire bender for inspiration.