FT_elliptical_gear_focal

thingiverse

Here is an elliptical gearwheel that fits Fischertechnik(TM) adapters. The axis is positioned in one of the focal points of the ellipse. A small 4mm boring marks the other focal point. A pair of these gears will work if aligned parallel, the smallest diameter meeting the largest diameter, axes at a distance of 60 mm. The design is strongly unbalanced. Remember to put counterweight if headed for higher rpm.