Updated: The larger/newer files have a negative spehere on the outside to consume less plastic, and the shaft is modified to fit the pololu/solarbotics motors.Wheel script designed for a sumo bot. allows for a nut, set screw and a channel to access the set screw with a straight screwdriver.Parametric in many ways, needs some adjustment for smaller diameter than 30mmopen with openscad, set the measurements in the beginning, compile and export.