Home instruction for sheet metal workers . produce a lines from 1° through cand d extending them until theyintersect the vertical lines pro-jected, from the extreme point 2and 4 in elevations at 2° and 2Vin plan. Take the length from 1°to 2V and set it off from 1° to 2Xon the line A B and draw thesemi-hexagon u 2V 2X 2° r. Then1° 2V, 1° 2X and 1° 2° representthe miter lines in plan. Make the semi-length of theroof piece from r to s, 5 in., as inthe scale drawing and completethe semi-plan r s t u. Numberthe corners in the hood in eleva-tion from 1 to 4, that of the shaftfrom 5
Home instruction for sheet metal workers . produce a lines from 1° through cand d extending them until theyintersect the vertical lines pro-jected, from the extreme point 2and 4 in elevations at 2° and 2Vin plan. Take the length from 1°to 2V and set it off from 1° to 2Xon the line A B and draw thesemi-hexagon u 2V 2X 2° r. Then1° 2V, 1° 2X and 1° 2° representthe miter lines in plan. Make the semi-length of theroof piece from r to s, 5 in., as inthe scale drawing and completethe semi-plan r s t u. Numberthe corners in the hood in eleva-tion from 1 to 4, that of the shaftfrom 5 to 10, and from thesepoints project vertical lines in theplan, cutting the miter line 1° to 2°, shown by similar numbers1° to 10°. Complete the half plan from these intersections, draw-ing the lines parallel to 2°, 2X until they cut the miter line 1° 2° ;from these intersections lines are drawn parallel to 2X 2V, cuttingthe miter line 2V 1°, from which they are drawn parallel to 2V auntil the center line is Fig. 237. Hexagonal Ventilator. 180 Home Instruction for Sheet Metal Workers As ornamentations are to be cut in flange 3 4 of the hoodin elevation, refer to the flange line, represented in plan on oneside by 4° 4X which measures 4 in., and as the semicircles in theflange are to be 1 in. wide, then space this line 4° 4X, so that 4X e,f h, i j and k 4° will be each % in. and c f, h i and j k each 1 in.,making the total of 4 in. Sometimes it becomes necessary to make a complete view ofthe elevation of the ventilator, showing the ornamental cuts inposition, when the small semicircles must be projected in the ele-vation from the plan as follows: Take any one of the spaces // i, in plan, parallel to which drawthe line 1 5 in V, upon which draw the semicircle 1 in. wide;space section V in equal spaces, in this case four, from which linesare drawn at right angles to 2X 2° until they cut 4° 4X between hand i. Take a tracing of V and place it in li
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Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1922
