Making frustums doesn't have to be frustrating
There are different methods for developing the patterns of these fittings; choosing whether the cone should be developed using radial lines or triangulation would depend much on the pitch or taper of the cone. The larger tapered cones are easily made using radial lines. As the taper becomes larger, the apex of the cone becomes closer to the drawing area. The smaller the taper, the further the apex becomes from the working area where the pattern is to be made. On the shorter tapers, especially in the larger diameter frustums, it would be more practical to use triangulation. Figure 1 shows the basic cone (A), frustum of a cone (B), truncated cone (C) and irregular section of a cone (D).