MAKE THE PIECES Cut two 3×30-inch backing strips and two 4½×24-inch rod support strips out of a 1×12-inch, No. 2 pine board. Round their corners using a saber or band saw.
SAW THE SLOTS Stack the two support strips together. Starting 2½ inches from the bottom, drill four centered holes 5½ inches apart using a 1-inch Forstner bit. Be sure to put a backer block under the bottom strip to prevent splintering when the bit breaks through. Then, with a saber or band saw, cut angled slots to meet the holes.
BORE THE BACKS Using a countersink bit, drill three ¼-inch-deep depressions into one of your backing strips: one at 6, one at 15, and one at 24 inches from the top of the strip. Using a 1/8-inch bit, bore holes through the center of these depressions. Repeat with the other backing strip. Finally, bore a centered hole 1½ inches from each end of the strips. You'll use these last holes to mount the rack on your wall.
ASSEMBLE THE RACK Sand all the pieces well. Then fasten them together by drilling self-starting wood screws through the countersunk holes in the backing strips and into the edges of the rod supports.
FINISH AND MOUNT IT Touch up with paint, stain, or polyurethane, and glue felt to the insides of the rod slots. Mount the pieces on the wall of your garage.