The crank shaft shown in Figs. 91 and 92 is quite a common example of steam-hammer work. The stock is first worked as illustrated in Fig. 167, the cuts being on each side of the crank cheek, and a special tool being used for this as illustrated. When the cuts are very deep, they should first be made with a hot chisel and then opened up with this spreading tool. With light cuts, however, both operations may be done with a spreading tool at the same time. Care must be taken when flattening out the ends, to prevent any of the material from doubling over and forming a cold-shut. After the ends are hammered out, the corners next to the cheeks may be squared by using a block as shown in Fig. 93.
Fig. 166. Squaring Up Work.
The forging illustrated in Fig. 89, while hardly the exact proportions of the connecting rod, is near enough the proper shape to give a good example of this kind of forging. The work is first started by making two cuts as illustrated in Fig. 168. The metal between the two cuts is then drawn out by using two steel blocks, Fig. 169, until it is stretched long enough for the corners of the blocks to clear the hammer dies; then the work is done directly upon the bare die.
Fig. 167. Diagram Illustrating Steam-Hammer Work on Crank Shaft.