Quad copter prop balancer

thingiverse

This prop balancer is designed to use with quad copter 11 inch props. However it will work with most props about that size for a fixed wing or copter. It is based in part on thing 180997 “three nail propeller balancer” by eddiema. It uses #10 3 inch long “bright common” nails. They have a diameter of .15 inches. These are standard in the U.S. and available from any DIY or hardware store. The bushing fits snugly into 11 inch APC brand props and the #10 nail fits snugly into the hole in the bushing. The bolts that hold the upright ends to the base are #4-40 and are ½ inch long. The holes in the ends are a bit smaller than clearance so the bolts will self tap into them. The counter-bore in the bottom of the base keeps the heads of the bolts from sticking out. This allows the base to sit flat on a level surface. Assemble by bolting the ends to the base (be sure the heads pull into the counter-bore and are below the surface of the base). Then push #10 nails through the holes in the ends so they form rails. You may need to lightly file off any bumps on the nails to assure they are smooth. Push the bushing onto a #10 nail and center it half way down the nail. Assemble a prop to be balanced by inserting any extra bushing piece that came with it into the hole in the prop. Push the printed bushing and #10 nail into the hole in the prop. Place the assembled balancer on a level surface. You may need to use a small level or bubble level to assure your surface is level. If the base of this balancer assembly is not level it will not work right. Place the prop with nail through it across the two rails. If the prop is not balanced it will roll on the rails and tilt to one side or the other. If you are unsure the base is level and the prop rotates to one side, remove the prop, rotate it 180 degrees and place it across the rail nails again. If it rotates to the same prop side it is unbalanced. If it rotates to the opposite prop side the base is not level. To balance the prop consult one of the numerous online sources for instructions. Usually these recommend either sanding the top of heavy side or add cellophane tape to the top of the light side. I have included the Sketchup file. If the bushing does not fit into the hole in your props you can draw another bushing and print it. The hole in the middle for the #10 nail has a diameter of 2.95mm and the bushing is 10mm long, although the length is not critical. Sorry about the mixed units. I drew this in mm but the nails and bolt are English units. I printed this in ABS on my Afinia H. It’s purple because that’s what I had in the machine at the time.