Fig. 2848.
Fig. 2849.
If the work requires to be swelled sideways we turn the fuller the other way around, as in [Fig. 2846], in which it is supposed that one side of the work is to be kept flat, hence no bottom fuller is employed. The action of a fuller may be increased in the required direction by leaning in the direction in which we desire to drive the iron; thus, suppose we require to spread the end of a rectangular bar from the full lines to the dotted ones in [Fig. 2847] and the first fuller across the piece as at a, [Fig. 2848], and then spread out the end by fullering, as in [Fig. 2849], inclining the fuller in the direction in which we desire to forge the iron.
Fig. 2850.
It is the roundness of the face of the fuller that serves to control the direction in which it will drive the iron, since the curve acts somewhat on the principle of a wedge. Suppose, for example, that the faces were flat, as in [Fig. 2850], and the iron would spread in both directions, the same as though the hammer were used direct, and if the work were intended to be kept parallel it would frequently require to be turned on edge to forge down the bulge that would form on the edge.