FT_elliptical_gear_focal

thingiverse

Here's an elliptical gearwheel that fits Fischertechnik(TM) adapters perfectly. The axis sits snugly in one of the focal points of the ellipse, while a small 4mm bore marks the other focal point with precision. When paired up and aligned parallel, these gears will work seamlessly together, with the smallest diameter meeting the largest diameter at exactly 60 mm distance between their axes. Be aware that this design is heavily unbalanced, so don't forget to add counterweight for any high-speed applications.