Well our laser cutter at the Fox.Build makerspace in St. Charles went sideways for a while and I did not have confidence that I could make good parts. It seems to be back on line so I am going to take another swing at this. The items I had concerns about are:
1) Too much friction. Mostly because the gears are too wobbly. The 3D printed axles worked pretty well but the pin to hold them in place was never done right.
--- To reduce part count, I will look at making a 3D printed axle which collapses on it self to get through the hole and then splays out to keep it in place on the other side. It may take some cut and try as my old Japanese boss used to say but I could save 8 parts and make assembly as snap, (Pun intended.)
2) More could be done to lock the board in place.
3) I am considering the worth of using better drivers. The L293D are the cheapest drivers on the planet at 0.25 but I think I am losing a volt. I might pay $0.75 extra to have a snappy robot. Maybe the mechanics can make it efficient enough that I will not need it but it is on the radar.
4) I want to implement a BMS. I am always concerned about running my expensive batteries into the ground. If you deplete the Li ion batteries too much, they will stop working or possible explode when charged.