Page:Sheet Metal Drafting.djvu/190

176 Starting at point 1 of the profile, the extension line should be followed downward until it intersects line 1 of the stretchout. In like manner all of the intersections should be located and marked with small circles. The miter cut may now be drawn in by connecting the intersections of the stretchout by straight and curved lines. It should be observed that curved lines in a profile will always produce curved lines in the pattern, and straight lines in the profile will produce straight lines in the pattern.

Figure 248 represents the moulding carried around another corner. Extension lines are carried upwards from this view and are intersected by correspondingly numbered extension lines from the profile. In this manner an elevation, Fig. 249, of any miter may be projected.

It should be observed that the plan, Fig. 246, plays no part in the development of the pattern, the extension lines from the profile remaining unchanged in passing through this view. This is true of all square (90°) return miters. However, if the miter was at any other angle, say 87°, the extension lines would be deflected by the changed position of the miter line, and a plan view would be absolutely necessary for the development of the pattern.