[EricH]

Originally Posted by M. Mellott

Last year, with 4 seperate bumpers, we used 1/4-20 carriage bolts (large, smooth button head backed by a square shank before the threads begin) through a thru-hole in the spec-size plywood--4 bolts for the longer sides, 2 for the front/back. The square shank bites into the plywood and keeps the bolt from turning while being tightened. The bolts ran through holes drilled into the side frame members (1.5"x1.5" welded aluminum tubing frame) and fastened by wing nuts that are hand tightened (i.e. no tools). [. . .]The only issue we had was placing the bumpers back on and getting 4 bolts through the blind holes on the inside of the frame rail--takes a little practie to do it quickly.

We had the same system, but used two on each of the 5 bumpers (one per side, two for the front). We also labeled the bumpers to show where they went and which way. Took 5-10 minutes, maybe 15. No wing nuts though.