Use stabilizer blocks to safely separate a box
When ripping a box, to separate the top and bottom, you need to prevent the parts from moving and pinching the blade when you make the final two cuts. Here's an easy way to do it. After ripping the sides (or ends) of the box, adhere suitably sized stabilizer blocks from 1⁄2 " scrap to the sides with double-faced tape, as shown, to hold the top and bottom in position and the kerfs open. Then rip the front and back to detach the top. To prevent interference between the blocks and fence, make the blocks 1⁄4 " shorter than the width of the sides and center the blocks on the sides.