Lay the fiberboard flat on a worktable, with one of the long sides facing you (like a computer keyboard).
Using a ruler and a pencil, measure and mark where the U-bolt rods will pass through the fiberboard: Make the first mark 3 inches down from the top edge and 1 inch from left edge. Then measure 2 13/16 inches down from the first mark and 1 inch in from the left edge, and make another mark.
Mark the next pair of holes 4 inches to the right of your first set, and repeat until you have 5 sets of marks.
Using a 5/16-inch bit, drill a hole at each marked point and remove any debris.
Now take one U-bolt and screw a hex nut onto each of its rods, twisting them up about one inch from the bottom of the rods. Slide a plate onto the pair of rods, then feed the ends of the rods through the first pair of holes in the fiberboard.
Attach an acorn nut to the end of each rod (to keep them from scratching your desktop). Adjust the nuts until all pieces feel secure. Repeat for each U-bolt.
1/2-inch-thick Homasote fiberboard, cut into a 9-by-18-inch pieces
Five 5/16-by-2 1/2-by-5 5/8-inch U-bolts, with their accompanying plates and hex nuts, nutty.com
Ten 5/16-by-1/2-by-17/32-inch nylon acorn nuts, mcmaster.com
Designer Stephanie Wenzel turned her no-frills apartment into a inspiring office and home with a little help from her local hardware store.
To tame her folders, invoice binders, and catalogs, Stephanie created custom desktop organizers by screwing U-bolts into blocks of 1/2-inch-thick fiberboard.