Today, I was able to perform the first full test of the crusher on my bot. I did not go well.

Two separate issues were encountered during testing. The first one is my fault, the second one is only  probably my fault.

Firstly, I underestimated (more like failed to estimate) how much force there would be trying to separate the final stage gears of my crusher. At some point I changed my design to make the front forks, and the shaft columns one piece. When I did this I moved the columns closer to the center line of bot, leaving the gear cantilevered at the end of the shaft. 

The gears are now pulling apart and slipping. The gears have a pressure angle of 20 degrees, and as it turns out there is almost 120 lbf trying to push them apart. Somehow, I will have to reinforce the end of the shaft.

The second problem I encountered is that the gear-motor I purchased is not capable of producing its advertised torque. Instead if you stall the output shaft and continue to run the motor, you will blow teeth inside of the gear box. I've now been able to reproduce this twice. It may be due to the end of the motor shaft being unsupported, but after seeing the tiny size of the gears inside the gearbox I suspect it is simply under engineered.

Luckily, I purchased a pair of these gear-motors and as each gear stage inside the motors is identical, I can swap gears between the gearboxes to get a functioning set. For now I'm simply limiting the current I'll send the motor until this issue can be resolved.

Based on my research, the majority of beetle-weight battlebots seem to have success with "lite-flite" wheels. I believe these were originally intended for model airplanes, but they have been used by a number of successful bots. Additionally, FingerTech Robotics make an excellent snap-hub that fits them and provides a secure connection. The wheels are a light-weight, resilient, and sticky rubber foam which seems to absorb major hits excellently. I decided to use these wheels and snap-hubs on my robot. Unfortunately, I discovered an interesting issue.

When my robot got up to speed and then tried to turn, the side load on the wheel would cause the wheel to deform underneath the edge of my robot, where it would become stuck. This could completely immobilize my robot. Unfortunately I couldn't get a good photo of this phenomenon, but I hope this diagram makes sense:

The fix to this turned out to be relatively easy. I fabricated some wheel stiffeners out of some 1/8" poly-carbonate and placed them inboard of the wheels. They worked great at resolving the pinching problem. I'm waiting to see if they start causing other issues thou. You can see them in this photo of the partially assembled bot:

Today, I finished fabrication on all of the custom components for Cpt. Hook. Originally, I had intended to fabricate the majority of the parts using the CnC mini-mill at the hacker space in town. Unfortunately this machine was down, and I ended up fabricating all the parts by hand using a band saw and drill press. At the end of the day I managed to hit a 1/16"  tolerance on every part, and I doubt for this machine there will be any issues. Here are the finished parts in all their glory:

I regret not documenting the fabrication process more. For next year, I am seriously considering a full build video detailing all the construction steps.