RC Crawler

thingiverse

***This is mostly for tinkering. YMMV if you try to print this*** Designed in FreeCAD-weekly v0.20 STL is only included to make thingiverse happy. Far too many parts to export each individually. Best way to open is by the FreeCAD file. In the attached STEP file, some parts appear to be missing -- they're just mirrors of the opposing part. I couldn't get everything to export properly in there. Electronics, shocks, and u-joint balls are from a Traxxas Emaxx. YMMV with other parts. Most places use M3 or M4 bolts of various lengths for attachment. Some spots I was able to make room for a nut, others, the bolt just screws into the plastic. Diffs are 12:1 worm-drive to achieve the gear reduction I needed. Gearbox is 4.91:1 for a total gear reduction of about 59:1. Gaskets were designed to allow the diff gears to sit in gear oil or grease -- the seal is a work in progress. Suspension is double-triangulated 4-link with helper extension arms at the top shock mounts to help articulation. Skateboard bearings are used everywhere except the axle shafts, which use nylon bushings to allow for larger diameter shafts. I used PLA for the hood for the color I had on hand, TPU for the gaskets, Nylon for the bushings and gears, and PETG for everything else. Weight distribution is a work in progress. It climbs like a mountain goat and descends like a soccer ball. Too much forward bias. Same with steering. Not enough servo output making its way to the front wheels. So that's a future upgrade.