WPL Crawler gearbox from original 180 motor gears

thingiverse

This is just a proof of concept. I don't know that I'll ever get around to developing it further. Just wanted to prove that it could work. Measurements stated might not be exact. It would be cool if someone more talented ran with it. :D I had a couple leftover 180 motor/gearboxes. The reduction gears are just a series of the same gear stacked with the last one having a wider contact area for the axle (output shaft). I wondered if a usable crawler speed would result from simply adding two more gears from a spare motor. ***The resulting speed is about half as fast as low gear in the 2 speed transmission.*** This would be usable for a crawler and is a decent speed for running around indoors. The pictures pretty much explain it. STL file is a 4mm gearbox extension. Shafts the gears ride on are 2mm in diameter (common for gear kits and model making). Those need extended 4mm for a total length of 17.5mm. The two gears taken from the spare motor are labeled reduction gear in the picture. Note that the top portion of the gear that contacts the output shaft is wider. Do not get this one mixed in with the reduction gears. Just stack the gears as they were originally, with an extra pair of reduction gears. The screws that hold the gearbox together also need to be longer. I had some 10mm long M2 screws that worked. I tried and failed to make an extended 3D printed motor mount, so ended up cutting one of the stock ones for testing. There wasn't output shaft poking out for the rear drive shaft, so my test was done in front wheel drive. So there it is. Just a proof of concept. It does work and the speed is about half as fast as low gear in the 2-speed transmission. My testing was done with ABS plus which shrinks, so the size may need adjusted for your filament. Side note: Not sure why anyone would want it, but the donor transmission can be put back together with two less gears resulting in a higher gear ratio. It would either need spacers or the output shaft can be flipped which leaves it extending far out one side only. Might work for a boat or rear wheel drive car. I did not do any testing with that setup.