If a straight pipe is to fit on to a curved bend, as shown in Fig. 315, it will be necessary to obtain the shape of the joint line before the pattern can be set out. This is very simply done by describing the semicircles, as seen on the figure; dividing up in the same manner, then running lines down and arcs around from centre C to intersect; thus giving points on the joint curve. The pattern (not shown) will then of course be set out in the usual way.
Any other junction of a straight with a curved pipe, either of the same or unequal diameters, can be marked out in a similar manner.