Simple solution for well-fitted shelves and dadoes
It's easy to machine shelves and dadoes that fit just a bit too tight. To avoid recutting either part of the joint, I simply sand the ends of the shelves with this handy block.
Make it from two pieces of 3⁄4 " hardwood held together with two machine screws and wing nuts. Offset the pieces by the depth of your dadoes. Loosen the wing nuts and flip over the sandpaper as it loads up.
—Merle Riesgaard, Conroe, Texas