[RRLedford]

We will be a 2013 4th year FRC team and have used both Bosch-Rexroth and 80/20 to a steadily increasing amount over all three prior years.

Last year however, we opted for using the KOP 6-wheel tank drive "kitbot on steroids" design with KOP framing for the wheels & gearboxes. This was to ensure that we had a drivable robot at the earliest possible time. The KOP channel is not very sturdy however, and with a 4-CIM drive train this KOP frame needs some stiffening. The 1" 80/20 extrusion fits nicely inside the C-channel to strategically stiffen it, and we then transitioned going upward to 80/20 frame above the drivetrain frame level for the rest of the robot structure.

Be sure to get a lot of the predrilled corner gusset plates for the high stress joints. The price is a bit stiff on the 80/20 line, especially the fasteners.

Get as many of the drop-in T-nuts that spin 90 degrees after insertion, as you can afford. These are available, for 1" (M8 slot width) in three thread tappings - 1/4-20, 10-32, and 6mm.
They are worth their extra cost to be insertable into any slot location no matter what else is already assembled into that slot. The nuts that roll into the slot are horrible and overpriced. most of the other 80/20 nuts are also a PITA to work with, so just try and standardize on the drop-in & twist T-nuts.

Buy a bunch of zinc plated chrome-moly B7 threaded rod and cut it to length when you require custom, longer length, bolt-thru-hole-in-frame assemblies.
Then by just adding a a flanged nut with serrated locking face at the threaded rod end opposite from the rod's slot end T-nut, a strong clamping action can be achieved for low cost. Over the years we accumulate more recycled pieces and it is great to use these for quick prototyping of ideas.

-Dick Ledford