Laying out for boiler makers and sheet metal workers; a practical treatise on the layout of boilers, stacks, tanks, pipes, elbows, and miscellaneous sheet metal work . o o po OS o 176 LAYING OUT FOR BOILER MAKERS the extremities of these lines, draw the outlines of thepatterns for throat and back. In Fig. 2, the dotted lines givethe front view of the cowl. The solid lines show the edgesof the pattern sheets in the flat before being worked intoshape, and on the working lines. In making the cowls of planished iron or steel, the back \S -I- I inch to meet the side pattern and then scarfed. The ed
Laying out for boiler makers and sheet metal workers; a practical treatise on the layout of boilers, stacks, tanks, pipes, elbows, and miscellaneous sheet metal work . o o po OS o 176 LAYING OUT FOR BOILER MAKERS the extremities of these lines, draw the outlines of thepatterns for throat and back. In Fig. 2, the dotted lines givethe front view of the cowl. The solid lines show the edgesof the pattern sheets in the flat before being worked intoshape, and on the working lines. In making the cowls of planished iron or steel, the back \S -I- I inch to meet the side pattern and then scarfed. The edgesof the side patterns are then scarfed and cramps cut to receivethe back and throat pieces, as shown in Fig. 9. They arethen fitted together and brazed. After the seams are dressedthe cowl is then rounded up and planished on suitable man-drels and heads. The finishing bead on the edge of the mouth of the cowlis made of a split tube, and is bent to shape around a woodensweep, the radius of the mouth, with a strip of metal in theslit to keep it from closing and also to keep the slit in thecenter. This method of making cowls is very flexible. The cowls. FIG. 6.—PATTERN FOR THROAT. PATTERN FOR BACK. FIG. 5. and side sheet.~ are worked down in the center on a hollowblock between tlie points LL, il/.l/ and 00. In working downthe centers, the edges of the sweep will rise to the edges of the throat-piece are peened to the sweep of thecurve and the center filled out afterwards. The four piecesare then rounded up and planished on suitable heads, fittedtogether, riveted, and a finishing bead put on the edge. Fig. 7 shows the front view of the throat piece worked intoshape. This is the most difficult to make, and care is re-quired in its manipulation. In making the cowls of sheetcopper, very little work is is performed before brazing. Thepattern sheets of the throat and back are bent to the work-ing lines, as shown in Fig. 3. the edges are worked over about
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Keywords: ., bookcentury1900, bookdecade1900, bookidl, booksubjectsteamboilers
