Page:Sheet Metal Drafting.djvu/191

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79. Conductor Head.—Conductor heads are used to ornament the conductor pipes of a building and are usually placed at the point where the "goose neck" from the gutter enters the conductor. As shown by the dotted lines in Fig. 250, a short piece of rectangular or round pipe is carried through the head in order to give a more direct travel to the water.

Conductor heads are made in a great variety of shapes and sizes. On the better class of buildings, they are designed to harmonize with the particular style of architecture adopted.

Figure 250 shows a front elevation of a conductor head. Since, as was explained in the preceding problem, the pattern may be taken directly from the profile as it appears in the elevation, the curved lines may be divided into small parts. It will be noticed that the space between points 20 and 21 is less than that between the other points. This is perfectly permissible, as long as the same distance appears between points 20 and 21 on the line of stretchout, and saves much time that would otherwise have to be spent in making all spaces exactly equal. The dividers are set at any radius not too large and the curve is spaced off, allowing the last space to come wherever it may.

A center line is drawn in Fig. 250 and extended downward to serve as a line of stretchout for Fig. 252. The spacing of the profile is now transferred to this line and numbered to correspond. Measuring lines are drawn at right angles to the line of stretchout and intersected by extension lines dropped from correspondingly numbered points in Fig. 250. The miter cut of one side of the pattern is now drawn in.

Since both sides of the front (as divided by the center line) are symmetrical, the distances from the center line of Fig. 252 to each point in the miter cut should be transferred to the other side, thereby obtaining the necessary points for drawing in the other miter cut of the pattern for the front.

The side elevation, Fig. 251, is now drawn and the pattern developed by the method already described for obtaining the pattern of the front. Laps are added and notched as shown in Fig. 253. Two of these patterns must be cut from the metal and while they