Page:Sheet Metal Drafting.djvu/237

Rh of their respective triangles and enable the true lengths of these lines to be measured.

An elevation of these elements is now drawn in Fig. 315. Where these elements intersect the miter line the elevation of points O, N, M, K, and H will be established.

A true section on the miter line, Fig. 316, is now constructed by transferring the spacing of miter line HD in Fig. 314 to any horizontal line. Perpendiculars are erected at each of these points and corresponding altitudes, taken from Fig. 315, placed on them. Lines connecting the points thus located constitute a true half section on the miter line. The whole section may be produced, if desired, by copying on the other side of center line H, the half already developed.

The pattern for the large branch is started by placing on any vertical line a distance equal to the hypotenuse of triangle 5 to G. The pattern is developed in the usual manner by following the order of development previously determined upon.

After the pattern for a complete transition has been developed the miter cut is drawn in as follows: The distance from point C to point O on the hypotenuse of triangle 3–O–C is laid off from point C on line C–3 of Fig. 320. Similarly, the distances C to N, B to M, B to K, and A to H are laid off from points C, B, and A on their corresponding lines in Fig. 320. A curved line passing through these points gives the miter cut of the pattern. Particular attention must be given to keeping the direction in which these measurements are taken, the same in the plan, in the diagram of triangles, and in the pattern.

In order to miter the small branch with the large branch, the same section must be used on the miter line. Figure 317 shows a half plan of the small branch removed from Fig. 314 in order to avoid confusion of lines. All of the intersections have been transferred and it is necessary to consider a new order of development which is given below.