(2) End cut use same numbers as for plumb cut but invert position of square.
e. Reduction for ridge. Measure straight back from plumb cut a distance equal to 3/ the thickness of ridge piece.
4. To Lay Out Hip or Valley Rafter.--
a. Plumb cut. (Cf. column 6) Take 17" on the tongue and 12" on the blade; scribe along the blade.
b. Side cut. (Cf. column 16) Take 17" on the tongue and 20.78" or 20-13/16" (columns 3 and 4) on the blade; scribe along the blade.
This also gives the miter cut at the end of the tail of the hip for fascia, and also the miter cut at the bird's mouth joint of valley rafter, where it must be cut out to fit the angle of the plate.
c. Length of hip or valley rafter. (Cf. column 12) 12½ (run of common rafter) x 20.78" (length of hip or valley rafter per foot of run of common rafter) = 21' 7.75" = 21' 7¾" (.75 = ¾, columns 3 and 4.)
d. Seat cut. (Cf. column 9) Take 17" on tongue and 12" on the blade, scribe along the tongue.
e. Tail for hip or valley rafter.
(1) Length determined as was that of hip or valley rafter, the horizontal projection of tail or length of the lookout of common rafter becoming the multiplier.