Gap-liners of steel or iron, or any other forgings of similar shape, are easily cranked by means of a couple of appropriate tools. Both the shaping tools may be used together as top and bottom tools, or the bottom tool may be the only one employed; in this case the bar to be cranked is driven into the shaping gap with ordinary fullers. A cranking implement of this class is shown by Fig. 230 ; such a tool may be used for small work that is to be cranked with hand fullers; or for large work, the tool may be fitted to a steam-hammer, and a steam-hammer fuller employed, instead of a hand fuller.

In this class of shaping implements, a broad gap is made across the shaper, for the convenience of using pieces of round iron for the purpose of cranking, when fullers of proper shape are not accessible. This gap for containing such pieces of round iron is shown in the Figure by I.

The piece of bar which is to be cranked with such an implement requires the intended cranked part to be equally heated, and that part of the work intended for the centre of the crank should be placed exactly opposite the centre of the gap in the cranking tool, that the straight ends of the work may be of proper length after being cranked; but when the bar to be cranked is several inches longer than necessary, the precise situation of the bar on the cranking tool is not important, the straight ends being cut to length after cranking.

These implements may be made having cranking gaps or grooves of various shapes, to suit many classes of work ; and to avoid casting a number of blocks, several cranking gaps may be made in one tool.