It seems like with the octagonal frame, you have room for 2" wide - if not wider - wheels. With the 4" Colsons coming in a 2" wide variety, is there any reason you opted to choose the 1.5" wide wheels?
Good catch. I had originally designed the drivetrain without the octagonal frame up top. Now that I’ve added it, I have room for the 2" wide wheels. The only qualm I have is that I won’t be able to use an e-clip to hold the wheels on the shaft because the WCP hubs are 1.5" thick. I suppose a screw, a washer, and some loc-tite would suffice. Thoughts?
It will be a bit more tedious than normal, but using a 1/2" snap ring would definitely be possible since you can fit a snap ring tool inside the small amount of space the Colson bore opens up. Alternatively, as you mentioned, a tapped hole with a screw, washer, and loctite will also be an effective method.
Another question - is your bellypan just not lightened yet, or are you using a solid piece of aluminum? If you don’t have the resources to waterjet a diamond-bellypan, I highly suggest using a solid piece of 6mm or 1/4" thick plywood as a bellypan. It’s much lighter than a solid aluminum plate, and will serve well as an electronics pan as well as providing the torsional stiffness the diagonals that a diamond bellypan provide.
EDIT: I was unaware you were referring to a socket wrench, not a regular wrench
My original post
In this particular scenario where there is a small, confined space for a tool to fit into, I’m not sure if you will be able to position a wrench in a way that allows you to get a significant torque advantage. A standard socket head should be sufficient to get the required torque, and the loctite will help in keeping things in.
MORT ran 2" wide colsons with this retaining method this year. We had issues on our practice bot with socket head screws and loctite not being enough to retain the wheel. YMMV, but I would recommend a hex cap screw.
Maybe I’m misunderstanding you, but I’m not understanding how you could fit a wrench inside the 1 3/16" bore of the wheel and hold it perpendicularly to the axis of rotation so that you can get the mechanical advantage to gain the extra torque.[/spoiler]
Compared to two snap rings, etc. it’s definitely sub-optimal, but with regular maintenance (check the bolts before a match) and some Loctite, it’s a decent enough solution that will retain wheels and account for manufacturing tolerances. Just don’t over-tighten the bolts as the tighter they are, the more preloaded your bearings are, and hex bearings seem to be particularly temperamental in FRC.
By the way, the wheels in 11’s photo are 2" wide black Colsons.
I’ll third the notion of not using thin polycarbonate as a structural belly pan. Polycarbonate is great for some applications but in this one the thickness you need for polycarbonate to be sufficiently rigid makes it a poor choice compared to thinner sections of other materials, such as garolite. We still use an un-lightened 1/16th aluminium belly pan though this is suboptimal.