Here I've just tapped the holes for nylon-tipped screws that will remove any vertical wiggle in the tail vise. That black thing is an aluminum block called the "dog block," because when it's all finished and mounted on the bench you can pop round benchdogs in holes in it to hold the wood you're working on. It slides back and forth on a metal plate screwed to the side of the workbench. You can see where it will fit on the right end of the newly made vise enclosure sitting behind it.