The only difference to be observed in cutting the patterns for elbows in elliptical pipes, as compared with the same operations in connection with round pipes, lies with the profile or section. The section is to be placed in the same position as shown in the rules for cutting elbows in round pipe, but it is to be turned broad or narrow side to the view, as the requirements of the case may be. In Figs. 318 and 319 are shown elevations and profiles of two right angled two-piece elbows in elliptical pipes. In Fig. 318 the broad side of the ellipse is presented to view, while Fig. 319 shows the narrow side, as indicated by the respective positions of the profiles. Although the results in the two cases are different in consequence of the position of the profiles, the method of procedure is exactly the same. Similar parts in the two drawings have been given the same reference letters and figures, so that the following demonstrations will apply equally well to either: Let A C E F D B be the elevation of the elbow and H G K I its section. Draw C D, the miter line. Divide the profile is the usual manner, as indicated by the small figures, and by means of the T-square placed parallel to the arm, drop points upon the miter line, as shown. Opposite the end of the arm lay off a stretchout, M N, and through the points in it draw the usual measuring lines.

Problem 39 The Patterns For A Two Piece Elbow In A 321

Fig. 318.

Problem 39 The Patterns For A Two Piece Elbow In A 322

Fig. 319.

A Two-Piece Elbow in Elliptical Pipe.

Reverse the T-square, placing it at right angles to the arm, and, bringing it in contact with the several points in the miter line, cut the corresponding measuring lines. A line traced through these points, as shown by L P O, will constitute the required miter.