Figure 3-47.—Finding the cutback.distance along the bottom quarter line. Make punchmarks with the center punch on each side of the line,along the side quarter lines. These marks will make iteasy to align the pipe for welding after the joint is cut.Use the spring steel wraparound and pull the loop tothe cutback point. Next, draw a chalk line over the tophalf of the pipe through the first cutback point.(NOTE: Do not allow the wraparound to twist orkink, and hold the chalk at a right angle to thewraparound while marking the pipe.) Now roll thepipe one-half turn and mark a chalk line in the sameway around the bottom half of the pipe.TWO-PIECE TURNIf a template is not available, you may determinethe dimensions and markings for the cut necessary fora two-piece welded turn of any angle between 1 degreeand 90 degrees by making a full-sized drawing, asshown in figure 3-48.Draw the center lines intersecting at b by using theangle of turn T and then draw the outlines of the pipesby using the center lines and the diameter D. Thesewill intersect at a and c. By laying the pipe over thedrawing so that point b will coincide with thatdetermined by construction details, you can draw thelines a-b and c-b in preparation for miter cutting andbeveling.After being prepared for welding, one section ofpipe should be rotated through 180 degrees to form thedesired angle, and then it should be tack-welded.Figure 3-48.—To locate cut on a pipe for any angle two-pieceturn.Spacing should be slightly greater at the inside of theturn.WELDED TEETo lay out the template for cutting the branch andheader for a 90-degree tee with header and branch ofequal diameter, draw the side and end view, as shownin figure 3-49, views A and B.In making the template for the branch in figure3-49, view A, draw lines 1-5 at 45 degrees to the centerline. Lay off distance 1-P equal to twice the thicknessof the pipe wall and draw the smooth curve s-P-s. Now,project point P from view A to view B and draw thelines P-t radially. At a distance above point t equal tothe thickness of the header wall, draw a-t horizontally,and vertical lines a-a and t-t. With lower points a ascenter, swing arcs r-s. Using the intersections of thesearcs as centers and with the same radius, draw thecurved lines a-be-d-e arid e d-c-b-a.Divide the outside circumference of the branchtop into equal parts and draw the vertical lines b-b, c-c,and so forth. Also, draw the horizontal base line a-a.Lay off the unwrapped circumference (fig. 3-49,view D), and divide each half of it into the samen u m b e r o f e q u a l p a r tsa s t h e b r a n chsemicircumference. In view D, you should plot thedistances a-a, b-b, and so forth, from view B. Thisgives the distances from the base line to the branchcurve of the intersection and determines the locationof the branch template.3-19