Having obtained he true profile E4 the pattern for the hip bar is obtained by drawing the stretchout line O P at right angles 1T 1P.

Take the stretchout of the profile E4 and place it on O P as shown by similar figures. Through these small figures and at right angles to O P draw lines which intersect by lines drawn at right angles to 1T lP from similarly numbered points at top and bottom, thus obtaining the points of intersections shown. A line traced through the points thus obtained, as shown by H1 J1 K1 L1 will be the pattern for the hip bar.

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 E2 being careful to have the points 1 and 4 at right angles to the line lx 1°. It is immaterial how far the section E2 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 E2 draw lines at right angles to the line 1° lx intersecting one half of the hip bar on similarly numbered lines as shown by the intersections 1L 2L 3L 4L 5L 6L and 1L 2J 3J 4L 5J and 6J; also intersecting the curb in plan at points lx 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 intersections with the hip bar, erect lines intersecting similarly numbered lines in the section as shown. Thus from the various intersections shown from 1L to 6L in plan, erect vertical lines intersecting the bar in the half section at points shown from 1L to 6L. In similar manner from the various points of intersections 3J, 5J, and 6J in plan, erect lines intersecting the bar in the half section at points shown by 3J 5J 6J. 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 stretchout can be used as that used for the common bar. Therefore, at right angles to D 4' and from the various intersections 1L 2L 3L 4L 5L and 6L 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 3J 5J and 6J in the one half section, draw lines at right angles to D 4' intersecting similarly numbered lines in the pattern as shown by 3J 5J and 6J. Trace lines from point to point, then the cut shown from N1 to P1 will represent the miter for that part shown in plan from 2L to 6L, and the cut shown from P1 to O1 in the pattern will represent the cut for that part shown in plan from 2L to 6J. 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 o p 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 letter 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

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Fig. 179.

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Fig. 180.

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Fig. 181.

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.

When a skylight is to be constructed on which the bars are of such lengths that the glass cannot be contained in one length, and a cross bar or clip is required as shown by B, in Fig. 150, which miters against the main bar, the pattern for this intersecting cut is obtained as shown in

Fig. 182. Let A represent the section of the main bar, B the elevation of the cross bar, and C its section. Note how this cross bar is bent so that the water follows the direction of the arrow, causing no leaks because the upper glass a is bedded in putty, while the lower light b is capped by the top flange of the bar C (See Fig. 150). Number all of the corners of the section C as shown, from 1 to 8, from which points draw horizontal lines cutting the main bar A at points 1 to 8 as shown. At right angles to the lines in B draw the vertical line D E upon which place the stretchout of the cross bar C, shown by similar figures, through which draw horizontal lines, intersecting them with lines drawn parallel to D E from similar numbered intersections against the main bar A, thus obtaining the points of intersections 1' to 8' in the pattern. Trace a line through points of intersections thus obtained which will be the pattern for the end cut of the cross bar.

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Fig. 182.

In Fig. 183 is shown a carefully drawn working section of the turret sash shown in Fig. 168 at A. These sashes are operated by means of cords, chains or gearings from the inside, the pivot on which they turn being shown by R S in Fig. 183. The method of obtaining the patterns for these sashes will be omitted, as they are only square and butt miters which the student will have no trouble in developing, providing he understands the construction. This will be made clear by the following explanation: