Page:Sheet Metal Drafting.djvu/183

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76. Liquid Measures.—The body of the measure should first be drawn and its side extended to locate the apex. Figure 240 shows such a view of the body with a half-profile attached to its top edge. This half-profile is divided into equal parts, and extension lines carried from each division to the top edge of the body.

Pattern of Body.—With a radius equal to the distance from the apex to point 7 of Fig. 240, an arc of stretchout, Fig. 241, is drawn. The spacing of the half-profile is transferred to the arc of stretchout with numbers to correspond. Straight lines are now drawn from the apex through points 1 and 7, continuing downward indefinitely. An arc drawn from the apex, with a radius equal to the distance from the apex to the point J, completes the half pattern of the body. A ¼-inch wire edge is added to the top of the pattern. A ¼-inch lock and a ⅛-inch single edge for double seaming are added as shown in Fig. 241. The half pattern is revolved about line 7 of Fig. 241 in order to obtain the full pattern.

Elevation of Lip.—The lip should now be added to the elevation of the body. In constructing the elevation of the lip, a point H is selected 1⅛ in. below the top edge of the body on the center line. Straight lines are drawn from this point through and beyond points 1 and 7. Point A is located ½ in. from point 1, and point G is located 1½ in. from point 7. The line AG completes the elevation. Extension lines must now be drawn from the apex (point H) cutting the top of the lip at points A,B,C,D,E,F, and G. From these points, horizontal fines are now shown intersecting the line HG, which is the slant height of the cone.

Pattern of Lip.—In any convenient space, an arc of stretchout, Fig. 242, is drawn with a radius equal to line H–1 of Fig. 241. Twice as many equal spaces are set off on this arc as there are spaces in the half-profile, with numbers to correspond. Measuring lines are now drawn from the point H through and beyond each division of the arc of stretchout. The distance 1–A, on fine HA of Fig. 242, is exactly equal to distance 1–A of Fig. 240. Distances HB, HC, HD, HE, and HF of Fig. 242 are obtained by measuring the distances from point H to the