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DEVELOPMENT OF PATTERNS FOR A HIPPED SKYLIGHT The following illustrations and text will explain the princi ples involved in developing the patterns for the ventilator, curb, hip bar, common bar, jack bar, and cross b a r or clip, in a hipped skylight. These princi ples are also applicable to any other form of light, whether flat, sinple-vitch. etc.

In Fig. 178 is shown a half section, a quarter plan, and a diagonal elevation of a hip bar, including the patterns for the curb, hip, jack, and common bars. The method of making these drawings will be explained in detail, so that the student who pays close attention will have no difficulty in laying out any patterns no matter what the pitch of the skylight may be, or what angle its plan may have.

First draw any center line as A B, at right angles to which lay off C 4', equal to 12 inches. Assuming that the light is to have one-third pitch, then make the distance C D equal to 8 inches which is one-third of 24 inches, and draw the slant line D 4.' At right angles to D 4' place a section of the common bar as shown by E, through which draw lines parallel to D 4', intersecting the curb shown from a to f at the bottom and the inside section of the ventilator from F to G at the top. At pleasure draw the section of the outside vent shown from h to 1 and the hood shown from m to p. X represents the section of the brace resting on i j to uphold the hood resting on it in the corner o. The condensa Fig. 175.

lion gutters of the common bar E are cut out at the bottom at 5' 6' which allows the drip to go into the gutter d e f of the curb and pass out of the opening indicated by the arrow. Number the corners of each half of the common bar section E as shown, from 1 to 6 on each side, through which draw lines parallel to D 4' until they inter sect the curb at the bottom as shown by similar numbers 1' to 6', and the inside ventilator at the top by similar figures 1" to 6'. This completes the one half-sec tion of the skylight. From this section the pattern for the com mon bar can be obtained without the plan, as follows: At right angles to D 4' draw the line I J upon which place the stretchout of the section E as shown by similar figures on I J. Through these small figures, and at right angles to I J, draw lines, and intersect them by lines drawn at right angles to D 4' from similarly numbered intersections 1' to 6' on the curb and 1" to 6" on the inside ventilator. Trace a line through points thus obtained ; then A' B' C' D' will be the pattern for the common bar in a hipped skylight. The same method

would be employed if a pattern were developed for a flat or a double pitch light. From this same half section the pattern for the curb is developed by taking the stretchout of the various corners in the curb, a b 3' 4' c d e and f, and placing them on the center line A B as shown by similar letters and figures. Through these divisions and at right angles to A B draw -lines which intersect with lines drawn at right angles to C 4' from similar points in the curb section a f. Trace a line through points thus obtained; then P f a will be the half pattern for the curb shown in the half section. V represents the condensation hole to be punched into the pattern between each light of glass in the sky light. As the portion c d turns up on c 4', use r as a center, and with the radius r s strike the semicircle shown. Above this semicircle punch the hole V.

Before the patterns can be obtained for the hip and jack bars, a quarter plan view must be constructed which will give the points of intersections between the hip bar and curb, between the hip bar and vent, or ridge bar, and between the hip and jack bar. Therefore, from any point on the center line A B as K, draw K L at right angles to A B. As the skylight forms a right angle in plan, draw from K, at an angle of 45°, the hip or diagonal line K 1°. Take a tracing of the common bar section E with the various figures on same, and place it on the hip line K 1° in plan so that the points 1 4 come directly on the hip as shown by Through the various figures draw lines parallel to K 1° one-half of which are intersected by vertical lines drawn parallel to A B from similar points of intersection 1' to 6' on the curb, and 1" to 6" on the ventilator in the half section, as shown respectively in plan by intersections 1° to 6° and 1° to 6°. Below the hip line K 1° trace the opposite intersection as shown. It should be understood that the section E' in plan does not indicate the true profile of the hip bar (whichmust be obtained later), but is onlyplacedthere to give the hori zontal distances in plan. In laying out the work in practice to full size, the upper half intersection of the hip bar in plan is all that is required. It will be noticed that the points of intersections in plan and one half section have similar numbers, and if the student will carefully follow each point the method of these projections will become apparent.