The Steel Square, Or Framing Square (Fig. 8) is often used as a try-square upon large work, though its most important use is in framing or roof construction. It is indispensable in finding the lengths and the angles of rafters, braces, etc. Its use for this purpose will be explained in "Constructive Carpentry." The long side of the framing square is known as the "blade," and the short side as the " tongue."

Fig. 8. - Steel, or Framing, Square.