Ordinary clip-in-place shelf brackets with slotted metal supports can hold a lot of weight. But some-times they’re unstable and can be easily knocked loose. The play in the slots allows the bracket and shelf to shift from side to side. To prevent this, use your circular saw to cut 1/8-in. deep slots into the undersides of the shelves, aligned with each bracket. When the shelf is assembled, the brackets fit into the slots, eliminating the sway.