In preparation for the rolling cart project, I was at the local Lowe's struggling to get a full sheet of 3/4 plywood and a full sheet of 3/4 MDF into the back of my mini truck. It "fit" by sliding it in at an angle with the bottom against one wheel well and the top sticking over the other side.
Since I can't fit a 4x8 sheet between the wheel wells, I needed to have a convienent way to stack the sheets over the wheels. I came up with this design, which seems to work quite well. It provides a stong platform just above the wheel wells and disassembles into four pieces without any tools. The four pieces can be stood up in the corner of the garage until I need them.
The platform is made out of four 2x4's, one 2x6, and a little 1/2" plywood to hold things together. Stacked edge to edge, the 2x4 and 2x6 give about 9 inches in height, which was about 3/4" above the wheel wells. I thought about ripping them down to be just 1/4" above the wells, but decided to keep it simple.
The bed liner has four molded indents where the 2x6 fits in snugly. All I had to do was measure the angle because the indents were not exactly verticle and I wanted the 2x6 to be held as tightly as possible. The other joy I discovered was that each indent was slightly different ranging from 5 to 7 degrees. I measure the first angle, then cut and test fit the 2x6. Each corner was then custom fit by increasing the angle a little until it fit.
After the 2x6 pieces were cut, I cut the cross pieces to length so they would also fit snugly. The long runners were cut to fit with the bed closed so I can drive to the store with the tailgate up. The tailgate end of the runners are supported with more 2x6. I cut a 45 degree slope on the end of the runner to help guide the sheets of wood up and on top of the platform. Also note that the runners are slightly higher than the cross pieces. This allows the sheets to slide into the truck bed without snagging on a cross piece.
I fasten the 2x4 and 2x6 pieces with a 6x9 piece of 1/2" plywood and some drywall screws. By avoiding glue, it will be easier to modify the structure in the future. Cutting those pieces of plywood was the most fun part of the project. In about 10 minutes, I had ripped two 6" strips of plywood on the table saw, then with a stop block clamped to the mitre saw, cut the strips to 9" lengths. I felt just like Ty from Trading Spaces!
In order to get everything screwed together in the proper position, I assembled everything in the truck bed, then clamped everything to a piece of plywood. I could then take it out and screw the plywood to the boards.
I now have over 50 inches of space for sheet stock! One possible future enhancement is to drill holes on the outside, top edge of each crossmember. I can then insert pegs in the proper holes to keep the wood from sliding side-to-side. I'll wait and see if that is really necessary.