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 . FIG. 26. beit determined by observation, as no definite allowance can bestated. It would be small at most. The bars may be bentto a comparatively short radius after the holes have beenpunched without tearing the metal from the rivet holes to theedge of the bar, or destroying the shape of the holes, by in-serting in the holes the small pieces which have been punched. FIG. 27. out. These will tend to keep the holes perfectly round
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 . FIG. 26. beit determined by observation, as no definite allowance can bestated. It would be small at most. The bars may be bentto a comparatively short radius after the holes have beenpunched without tearing the metal from the rivet holes to theedge of the bar, or destroying the shape of the holes, by in-serting in the holes the small pieces which have been punched. FIG. 27. out. These will tend to keep the holes perfectly round, and thesmall pieces may easily be knocked out after the bar is bent. CONICAL SURFACES. Conical surfaces may be developed by a method some-what similar to that used with cylindrical surfaces. A crosssection of the cone is divided into a number of equal parts. cated in Fig. 24. For inside angles, if Z? is the outside diameter and lines are drawn on the surface of the cone from these i8 LAYING OUT FOR BOILER MAKERS points to the vertex. For instance, in Fig. 25 the circumfer-ence of the base of the cone is divided into sixteen equal parts,and lines are projected from these points of division to thebase of the cone in the elevation. These points are then con-nected writh the vertex of the cone A. It may then be seen thatthe surface is divided into a number of triangles, the sides ofwhich are elements of the cone, and therefore equal to the dis-tance Al, and the bases equal to the length of the equal divis-ions shown in the p
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Keywords: ., bookcentury1900, bookdecade1900, bookidl, booksubjectsteamboilers
