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