2 mating parts are needed. First is a gear with a special section cut out in the center. 12 pitch, 20 degree pressure angle, 36 teeth. It should be 0.75 inches thick, 6061 aluminum. See ShockGear.DXF.
Second part: mating piece which fits inside the slot in the gear. 1 inch thick, 6061 aluminum. 0.75 inch hole with keyway. See shockGearInsert.DXF.
I'm guessing waterjet cutting would be best, but am open to suggestions. I only need 1 of each, maybe 2 if the price is right.