A question in roof framing which sometimes comes up in actual practice is how to cut the bevel on the lower end of a hip or valley corresponding to a square cut of the common rafter. This is only used in cutting the ends of hip and valley rafters preparatory to nailing on the fascia and crown molding. Every carpenter knows that a square cut on a hip or valley will not correspond with a square cut on the common rafter.
This cut may be obtained in the following manner:
Take 17 inches on the blade of a square and one half the rise of the common rafter to a foot run on the tongue, and the tongue gives the cut.
Fig. 114 - Manner of Applying the Steel Square to Obtain Bevel for Hip or Valley Rafter.
For example, suppose I have a roof of one-third pitch. This being a rise of 8 inches to the foot run, 8 and 12 will make the common rafter cuts and 17 and 4 the cut on the end of the hip or valley corresponding to a square cut of the common rafter. Fig. 114 shows the manner of applying the square for the purpose of obtaining the bevel on the lower end of a hip or valley rafter.