Hidden cleat hangs brackets with no visible support
Rout a stopped groove in the back of your shelf brackets, and use that space to make a hidden cleat. Rout the groove as shown in the illustration below. Now, cut a cleat that fits snugly into the groove and flush with the back edge of the bracket. To complete the cleat, cut it in half at a 45° angle, screw the bottom, part B, to the wall and glue the top, part A, to the bracket as shown. Slip the bracket over the wall-mounted section of the cleat and you have a strong and completely invisible support.
—Joseph W. Mott, Binghampton, N.Y.