A roof framing square has a triangular body (2) with an arcuate slot (20) adjacent its hypotenuse side (16) and an arcuate-sided aperture (22) spaced inwardly therefrom. Both arcs (20, 24) are defined by radii having as their centre point a pivot aperture spaced from the first side (10) along the vertical second side (12). A pivot pin seated in the pivot aperture pivotably mounts on the body (2) a protractor arm (4) which is comprised of arm elements disposed on the opposite surfaces of the body. The protractor arm (4) may be secured in a pivoted position by a clamping screw (8). An angular or protractor scale (48) is provided along the arcuate edge (24) of the aperture (22), and two scales (45, 58) which convert the unit rise per unit length data to angular positions are provided along the opposite sides of the arcuate slot (20). The protractor arm (4) is set at the desired angular position, and the square placed upon the board with the appropriate surface of the protractor arm (4) seated firmly thereagainst so that the scribe line may be drawn along the designated side of the square. IMAGE
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