Join Date: Nov 2008
Location: Longview, WA (one hour north of Portland, OR)
So we got the box bolted to the frame. It took 35 bolts (one inch long 5/16" stainless steel button head bolts). We used another 12 (six on each end) same-sized bolts through the upright portion of the angle iron (second picture).
What's interesting, is the box is built such that all four sides fold under to the floor only about 3/4", forming a lip. A large sheet of non-diamond plate aluminum is then laid down on top of this lip and welded in place (and sealed with silicone). Which is fine I guess, but what happens is there's a gap between the trailer frame (which is 2" wide at the top) and the bottom of the floor of the trailer. So most of the holes were bolting through the flooring and not the diamond plate. Some of the holes when through the edge of the diamond plate where it ended and the floor began. So we put washers between the floor and the frame before bolting it down (the diamond plate lip was resting on the frame). On the center crossmember we put a piece of steel 1/4" thick to fill the gap.
So when you think about it, the box was bolted down by the flooring only, and not through the diamond plate lip. Part of my plan to fix that was to put 2" angle iron 1/8" thick front and rear (to fill in the gaps), and not only have holes drilled through the angle where it sat on the frame, but also in the upright portion so it attached to the diamond plate front and end pieces. I hope the pictures help.
We also took the rubber mat that used to be on the floor of the trailer when it was a wooden box, and put it in the new box after drilling holes so the rubber mat would go over the bolt heads (the mat's not bolted to the floor). You can see how much extra space the new box has.
Next up: mounting the spare tire and gas cans.