Page:Sheet Metal Drafting.djvu/95

Rh The slant height lines are also elements of the surface of the cone, and are the only elements shown in the elevation that represent the true distance from the base to the apex, along the surface of the cone.

The Arc of Stretchout.—With one point of the compass on the

apex, and a radius equal to the slant height, an arc, Fig. 117, is drawn. Upon this arc, as many spaces are laid off as there would be in the whole profile, Fig. 116. Since this arc answers the same purpose as did the line of stretchout in parallel line drawing, it