Fig. 59. - Diagram for Half Pitch Roofs.
Before proceeding further with the subject of roof framing we will illustrate a very simple method for obtaining the bevel across the back of jack rafters, or any rafter which cuts on a bevel across the back. Referring to Fig. 60, draw the plumb line or pitch of the roof on the side of the rafter B C. Next draw another plumb line the thickness of the rafter from the first, and measured square from B C, as shown by the dotted lines. Square across the back of the rafter, from the dotted plumb line to A. Connect A with B, and the lines to follow in cutting are A B C. This plan is worth remembering, as it will work on roofs of any pitch, and, in fact, will cut the bevel across the back of any rafter which cuts on a bevel. It is the plumb cut and the thickness of the rafter applied in the manner described that does the business every time. After the cuts have been found bevels can be set for them if desired.