Remix of Dual Mode Spring Motor Rolling Chassis

thingiverse

I really liked this design that Greg Zumwalt made. I started off just redesigning the rear wheels so I could use the #222 O-Rings from http://www.harborfreight.com/382-piece-o-ring-assortment-67554.html since this o-ring set did not have the #223 size. Initially I thought the wheels might be too complex for me to modify, but they turned out to lend themselves well to modifying. After printing a couple of the smaller gears, my printer had problems printing to these tight tolerances. I decided to modify the parts that I wanted to change the tolerances on. The gearing took the most effort for me since I am not familiar with designing gears. Fortunally I found this cool openscad script http://www.thingiverse.com/thing:5505 that made it rather easy to create the gear changes I needed. I made several rear wheel versions using #222 & #325 O-rings and for the front wheels #213 & #214. In the file name the number following OR (OR222) defines the o-ring used and the 1x,2x,3x or 4x defines how many o-rings per wheel are used. I have not printed all the iterations of these. If you need another size or I miscalculated something, let me know & I will try to accomodate. I printed these using eSun Silver PLA+ at 20% infill, .2mm height with a .4mm nozzle. Slicing was with slic3r 1.2.9. Printing took about 12 hours & used 3.9oz of plasitc. My 1st test crank of this vehicle did not work well. All I needed to do was sand a little more where the large idler gear connected. The wheels also come off sometimes, so I am going to super glue them on now that everything seems to be working ok. If you want to avoid more sanding like I do, I made a version of the Idler_Small & that axle combined (Gear_Idler_Small_And_Axle_Mod_Rev11.stl) as well as the Rear axle & that gear combined (Gear_And_Axle_Rear_Mod_Rev11.stl). I added 4mm to the height of the idler axle. I just printed the Gear_And_Axle_Rear & it looks pretty good. You will have to print these with supports, but the gears are small so not that much support needed. I included the openscad files & STL files so you can change any hole or shaft sizes that do not work for you. For further info & assembly instructions of this see the original design of this part: http://www.thingiverse.com/thing:2025760