At first glance it looks like a combination square on steroids, but further examination shows that the Douglas Quad Square is much more. I think it's one of the most useful layout tools I've used in more than 40 years of work as a builder. The 16-inch-long blade will square across a 2x12, and the 11/2-inch-wide blade is excellent for plate layout. The handle (the short legs of the combination square) are a full one inch thick, leaving 7/16 inch on each side to hook over the edge of a board. This means on lumber with wane, you're more likely to get an accurate line. For its size, the Quad Sqaure is surprisingly light, too, so carrying
