Page:Sheet Metal Drafting.djvu/167

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68. Ash Pan with Semicircular Back.—Figure 206 shows the plan of an ash pan having a semicircular back. The sides and back flare 1⅛ in., while the front of the pan flares 1½ in. Figure 207 shows an elevation of the pan. The pan is made from five pieces of metal (two sides, front, back, and bottom), all joints being double seamed. The top is reinforced with No. 8 wire.

Pattern for Semicircular Back.—The plan and elevation are drawn according to the dimensions given in Figs. 206 and 207. An extension line is carried downward from the center from which the semicircular ends are drawn. Another extension line from the slant height (line 16–17 of Fig. 207) is drawn to intersect the first extension line, thereby locating the apex of the cone of which the semicircular end is a part. With the apex as a center, and a radius equal to the distance from the apex to point 17 in Fig. 207, the arc of stretchout, Fig. 208, is drawn. The spaces 2, 3, 4, 5, 6, 7, and 8, taken from similarly numbered spaces in Fig. 206, are set off upon this arc. The pattern is completed by an arc drawn from point 16, using the apex as a center. One-half inch locks are added to both edges of the pattern, a ⅜-inch wire edge to the top and a -inch single edge to the bottom of the pattern.

Pattern for Sides of Pan.—Extension lines are dropped from points 9, 13, and 8 of Fig. 206. At any convenient location the horizontal line 9–8 of Fig. 209 is drawn. Parallel to this line, and at a distance equal to line 16–17 of Fig. 207, the horizontal line 12–13 of Fig. 209 is drawn. The intersections of these lines with the extension lines previously drawn will determine the location of points 12 and 13. Lines 8–12 and 9–13 are drawn. A ⅜-inch wire edge is added to the top, and a -inch single edge to the bottom of the pattern. A ½-inch double edge is added to side 9–13 for double seaming. These patterns must be formed "right and left" in making the pan. The rivet holes for the bail ears must be located as shown in Fig. 209.

Pattern for Front of Pan.—The line 9–1 of Fig. 211 is drawn equal in length to line 9–1 of Fig. 206. A line is drawn parallel to this line and at a distance equal to line 14–15 of Fig. 207. Perpendiculars are dropped from points 1 and 9 of Fig. 211 cutting