pic: 176 Prototype 6WD Rev. 7

[artdutra04]

Originally Posted by JesseK

If we applied the previous years' rules regarding frame behind the bumper, the corners of this frame wouldn't pass inspection. The entire length of the bumpers must be supported with no gaps under those rules.

This is solveable by replacing the aluminum angle with a regular 80/20 member, and using 80/20 corner anchors to attach the frame members together. The round pockets for the corner anchors can be milled in either a milling machine or a carefully aligned drill press jig.

[Dale]

If you do use the 80/20 inserts above be sure check them for tightness after every match and use Loctite. They tend to vibrate loose because they don't have the natural "lock washer" properties of things mounted on the sides of the extrusion. These little inserts are very strong and much lighter than L brackets and plates but they can be a pain if they become loose in a hard to access place.

[AcesJames]

Thank you guys for all of the comments thus far!

This will be our first year building just about anything with 80/20, and to go straight to a frame with it is a little nerve-racking. All other robots we've ever built have been either box or angle aluminum, welded by one of our sponsors. Unfortunately, we don't know if we have that option yet, and that was the impetus for trying some CAD with 80/20.

I appreciate the advice on tightening methods, because that's one of the key things we're worried about. Also, thank you guys for the mention of not needing as much support as we've added. I'm going to bring this info to our next meeting and we'll work accordingly.

James