Begin by cutting the interior box sides from the 1/2" plywood by cutting 3.5" strips across the entire sheet. From these strips you'll need to cut 18 pieces at 6.5" long and 18 pieces at 7.5" long.
Measure and mark your cuts. Onto your plywood material. With your material clamped to your workbench, cut along your marked strips using a Dremel Saw-Max tool equipped with the Wood & Plastic SM500 blade. You'll love how quickly and easily you can make these cuts with this one-handed tool.