This tool is extremely useful for scribing lines parallel to a given surface. It is made of steel and the head is hardened. The gage is securely locked by a knurled clamp screw and split bushing in the head. The marker is a square piece of thin tempered steel firmly held against the edge of the beam by a screw. The beam is graduated a full 6in by 64ths of an inch, and fine adjustments may be made by a slight rotating movement of the head.