Side Or Cheek Cuts Of Hip And Valley Rafters For Roofs Of Any Number Of Sides. Fig. 74 illustrates the principles involved and method used in determining side cuts whatsoever the pitch and number of sides involved. (1) Lay the square across the jack or hip or valley, whatever is to be framed, at any convenient place, using on the blade the tangent (with 12" as base) of the polygon being framed, and on the tongue the constant of the run of the common rafter, 12". Scribe along the tongue A-C, Fig. 74. (2) With the square, carry the line B-C across the edge as indicated. (3) Lay off the plumb cut for the required pitch, taking upon the blade the rise, and upon the tongue the constant of the run of the hip or valley or jack, according to the requirements for that par-
Laying off Side Cut of Jack, Hip or Valley, any Polygon ticular member as determined by the style of roof. (4) Measure square back from this plumb cut line the distance A-B of Fig. 74. (5) Thru point A scribe a line D-A parallel to that of the plumb cut line and (6) square this across the edge as at D-E. (7) Adjust the bevel to pass thru E and F, Fig. 74. (8) Scribe a plumb cut line upon the reverse surface of the stock.
It will be observed that in one case the square is laid across the edge with 12 " on the tongue and 12 " on the blade, Fig. 74-a. This, as might be supposed, is for finding the cheek or side cut for jack, hip, or valley where the junction angle is 45°. In the case of the octagonal hip, valley, or jack 5" must be taken upon the blade, since that is the tangent value of 22½°, 12" as base being taken on the tongue, Fig. 74-b. This tangent value will vary, then, according to the change in the junction angle.
The reason for using the tangent and run for this work is indicated by the position of the square on the plan of the roof, Fig. 75. These figures are for use only when the timbers lie in the plane
Securing Value of A-B of Fig. 74, Various Angles of the plate, or any parallel plane. When rafters take on pitch or rise, however, the upward projection of the plan of the miter cut, Fig. 74, will determine the side cut as just described.