While woodworking my own wall shelf, I also planned to router the back of the body of wood, so it would sit over the wall shelf bracket.

Unfortunately, the wood listed as thicker than the bracket actually measured as thick as the bracket, after I already bought it. I can't router that! Well, not easily.

People don’t want quarter-inch drill bits. They want quarter-inch holes.

Similarly, I just needed an appropriately-shaped hole in the back of my piece of wood. I figured out with the public makerspace member that instead of routering, we could “anti-router.” They cut some of the extra wood to glue to the side, to hide the wall shelf bracket - much easier!