This design seeks to minimize the parts count of a 3d printed robot chassis. All of the hardware for the chassis costs less than $10. The Motors batteries and motor controller can be substituted for any of your choice. I hope to convert the final design to OpenScad so that the design is parametric. The gears on the rear wheels and motor were made on a customized version of Blender's gear Generator. For those who which to generate their own gear ratios here are the stats of the gear around the rear drive wheels:Number of teeth 50pitch 4mmclearance .5mmwidth 2.5mmbase 4.2mmPA 20dI am not providing the Blender script at this time because it is a bit of a hack and in the future I hope to convert the design to OpenScad anyway.