Predrill holes in the boards for the screws. For each of the 15-inch boards, you’ll need 2 holes, placed 3/8 inch from the bottom (in order to connect with the plywood) and about 6 inches from each end. For each of the 21 1/2-inch boards, you’ll need 6 holes. The first 2 should be 3/8 inch from the bottom and 6 inches from each end, like the other boards. Drill the remaining 4 holes in each of the board’s 4 corners, where the longer boards will overlap the 15-inch ones.
Start with the two 15-inch boards. Affix them at opposite ends of the plywood with carpenters’ glue (use a waterproof formula if tray will be used outside), aligning the bottom of each with the bottom of the tray, as shown in illustration, and then insert the 1 1/2-inch screws. Repeat with the 21 1/2-inch boards. Let dry.
Position each one far enough in so the wheel doesn’t extend beyond the edge of the tray. Using the 3/4-inch screws, anchor the casters.
Wooden tray template
Four 1-by-2-inch boards: two cut to 15 inches and two cut to 21 1/2 inches (for guards)
3/4-inch-thick plywood, 15 by 20 inches (for tray)
Carpenters’ glue (standard or waterproof formula)
Sixteen 1 1/2-inch wood screws (for guards)
4 swivel-plate casters with 2-inch wheels
Sixteen 3/4-inch wood screws (for casters)
When purchasing wood from a home-supply store or lumberyard, note that the stated, or nominal, measurements will be slightly larger than the actual measurements. (The larger number reflects the presanded size; what you’re buying is already sanded.) For example, a 1-by-2-inch board is actually 3/4 by 1 1/2 inches, and a 1-by-12-inch board is really 3/4 by 11 1/4 inches. We’ve included the nominal measurements in our illustrations and materials list so that you’ll know what to look for when you go shopping.
Wooden Tray with Casters Attach casters to a wooden tray to ease the burden when transporting heavy items such as potting soil and fertilizers. The instructions below are for a shallow dolly that measures 15 by 20 inches —large enough to hold a plastic storage bin but small enough to store and maneuver.