The wobbly old string-and-a-nail technique for marking arcs and circles often leads to errors. But with our shop-built trammel, you can scribe perfect arcs or circles of any size—and do it quickly.
To use the trammel and create an arc, stick the clipped 4d nail on the head into the planned arc's centerpoint. Slide the pencil end of the beam out to the desired radius and tighten the wing nut on the side of the head, locking the beam in place. To scribe the arc, hold down the head and swing the pencil end of the beam. For an extra-large arc, make a longer beam.
—from the WOOD® magazine shop