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56 It has already been shown that all miter cuts in the same elbow are exactly alike as to shape and size. Therefore, it is only necessary to reverse the pattern of the big end to get the miter cuts for the other pieces. Figure 84 shows all four pieces as they would appear when laid out on the metal in the shop. The man in the shop cuts a rectangular piece of iron the proper size, sets off the

of the backs and throats, and by reversing the pattern for the big end, gets the entire layout. The section in the lower right-hand corner. Fig. 85, shows the method used to join the pieces of the elbow together. An elbow made in this manner is known to the trade as a "peened elbow." The single and double edges are prepared in the turning machine (thick edge) and, after being slipped together, the double edge is clinched over the single edge with the peen of the hammer.