The robot got a lot of use by enthusiastic riders in a few months (among them was my young cousin who drove it back and forth for hours when I brought it home over Christmas break), and this led to discovery of a few design flaws.
This project was funded directly out of my pocket, so in the interest of saving money I skimped on a few things. One of those things was not adding bushings to any of the rotating joints. It soon became apparent that the main drive linkages weren't going to last long without them. This Instructable is going to show you what you need to do repair them.
Step 1: The Damage Done
Also, the steel legs rubbing on the drive bolt did some hefty damage to the threads. The steel on steel contact isn't that much of a concern to me at this time, so I'll only be focusing on the aluminum-steel interaction.
Step 2: What You'll Need
2 flanged bronze bushings for 3/4" shaft diameter, 1inch length under flange, 1 inch outer diamater (I used McMaster-Carr part # 6338K434)
2 grade 5 3/4-10 x 5 inch long hex bolts (McMaster-Carr part # 91247A855)
Drill press, or mill
1" drill bit
Step 3: Hole Enlargement
This whole repair is pretty simple. Disconnect the legs on Hexabot so you can remove the drive linkages. Clamp the linkage securely on your drilling device of choice and align the worn drive hole with the drill spindle. Chuck up the bit , and enlarge the hole.
Step 4: Press Fitting the Bushing
Please note that the side of the linkage the flange is on is important. When the linkage is reattached to the robot, you want the bushing flange facing outwards. See the other pictures on this step for further clarification.
Step 5: Reinstallation
Reattach all the legs and linkages, tighten locknut onto the drive bolt, and enjoy the smoother ride of your hexabot!