Concerning the mortise and tenon attachment being used on a drill press, how or what is the best way to square the fence to the drill bit?
Rob Johnstone: The task is simple enough. But it is not the fence you need to worry about, it is the drill press table. Most drill press tables adjust on a single axis … we’ll call it “side to side” for our discussion. So, the first step is to use a small square and align the table to the mortising bit. Once that is correct you need to be able to adjust the second axis. The easiest way to accomplish this is to put a flat platform made from a piece of sheet stock — MDF, melamine or plywood — onto the drill press table. Check it for square “front to back.” If you need to adjust the platform, simply shim it until it aligns your square properly. Secure it with clamps or even screws (driven up from under the drill press table), and you are ready to mortise. Now, if you have square stock, all will be right with the world … and your mortise and tenon joints.