Having obtained the true points of intersections in plan the next step is to obtain a diagonal elevation of the hip bar, from which a true section of the hip bar and pattern are obtained. To do this draw any line as R M parallel to K 1°. This base line R M has the same eleva tion as the base line C 4' has in the half section. From the various points 1° to 6° and 1" to 6° in plan, erect lines at right angles to K 1° crossing the line R M indefinitely. Now measuring in each and every instance from the line C 4' in the half section take the various distances to points D 1" 2" 3" 4" 5" and 6" at the top, and to points 1' 2' 3' 4' 5' and 6' at the bottom, and place them in the diagonal elevation meas uring in each and every instance from the line R M on the similarly numbered lines drawn from the plan, thus locating respectively the points N 1r 2r 3r 4r 5r and 6T at the top, and 1" 2" 3" 4" 5" and 6" at the bottom. Through the points thus obtained draw the miter lines 1T to 6T and 1" to 6" and connect the various points by lines as shown, which completes the diagonal elevation of the hip bar intersecting the curb and vent, or ridge. To obtain the true section of the hip bar, take a tracing of the common bar E or E' and place it in the position shown by being careful to place the points 1 4 at right angles to 1" as shown. From the various points in the section at right angles to 1" 1T draw lines intersecting similarly numbered lines in the diagonal elevation as shown from 1 to 6 on either side. Connect these points as shown; then will be the true profile of the hip bar. Note the difference in the two profiles; the normal E' and the modified E'.
For the pattern for the jack bar, take a tracing of the section of the common bar E and place it in the position in plan as shown by E' being careful to have the points 1 and 4 at right angles to the line 1z 1°. It is immaterial how far the section is placed from the corner 2° as the intersection with the hip bar remains the same no matter how far the section is placed one way or the other. Through the various corners in the section Ex draw lines at right angles to the line 1° 1" inter secting one half of the hip bar on similarly numbered lines as shown by the intersections 2L 3" and P 2J 3' 4L 5' and 6'; also inter secting the curb in plan at points 1' to 6x. The intersection between the jack bar and curb in plan is not necessary in the development of the pattern as the lower cut in the pattern for the common bar is the same as the lower cut in the pattern for the jack bar. However, the
intersection is shown in plan to make a complete drawing. At right angles to the line of the jack bar in plan, and from the various inter sections with the hip bar, erect lines intersecting similarly numbered lines in the section as shown. Thus from the various intersec tions shown from 1" to 6" in plan, erect vertical lines intersect ing the bar in the half section at points shown from 1' to 6L. In similar manner from the various points of intersections 3', 5', and 6' in plan, erect lines intersecting the bar in the half section at points shown by 3' 5' 6'. Connect these points in the half section, as shown, which represents the line of joint in the section between the hip and jack bars.
For the pattern for the upper cut of the jack bar, the same stretch out can be used as that used for the common bar. Therefore, at right angles to D 4' and from the various intersections P. 2'' 31. 41' and 6" draw lines intersecting similar numbered lines in the pattern for the common bar as shown by similar figures. In similar manner from the various intersections 3' 5' and 6' in the one half section, draw lines at right angles to D 4' intersecting similarly numbered lines in the pattern as shown by 3' 5' and 6'. Trace lines from point to point, then the cut shown from to P' will represent the miter for that part shown in plan from 2L to 6L, and the cut shown from to in the pattern will represent the cut for that part shown in plan from to 6'. The lower cut of the jack bar remains the same as that shown in the pattern. The half pattern for the end of the hood is shown in Fig. 179, and is obtained as follows: Draw any vertical line as A B, upon which place the stretchout of the section of the hood m n op in Fig. 178, as shown by similar letters m n o p on A B in Fig. 179. At right angles to A B and through the small letters draw lines, making them equal in length, (measuring from the line A B) to points having similar letters in Fig. 178, also measuring from the center line A B. Connect points shown in Fig. 179, which is the half pattern for the end of the hood. For the half pattern for the end of the outside ventilator, take the stretchout of h i j k l in Fig. 178 and place it on the vertical line A B in Fig. 180 as shown by similar letters, through which draw horizontal lines making them in length, measuring from A B, equal to similar letters in Fig. 178, also measuring from the center line A B. Connect the points as shown in Fig. 180 which is the desired half pattern. In Fig. 181 is shown the half pattern for the end of the inside ventilator, the stretchout of which is obtained from F 1" 2" 3" 4" H G in Fig. 178, the pattern being obtained as explained in connection with Figs. 179 and 180.