[Neil B]

Firstly, I'd suggest you only take the illustration of bumpers in the manual (Figure 8-1) as a recommendation, not an actual design. From what I can tell, it shows the bolt as the part that goes through the frame and using T-nuts in the plywood. I can say from experience that that is a very bad plan. When we used T-nuts on our bumpers in '06 they completely chewed up the holes they were originally set in after a few matches and lost their grip on the plywood. That meant that we had to spend a lot of time taking the cloth off our bumpers to search for t-nuts that had worked their way loose; making those particular fastening points unusable.

I would suggest that you place the bolts inside the bumper and sticking out the back. Just drill a few holes in the chassis, slip the bumper on and attach nuts; it was a 5 minute job for the whole robot and we could usually attach the bumpers completely while queuing for our next match.