Fig. 2970.
To finish the hole the forging was then placed in a block such as shown at g, in [Fig. 2970], a finishing punch being shown at h in the figure.
Fig. 2971.
The next operation was to let the steam hammer down upon the face of the punch and bring up the wings e f parallel, but not more than parallel, as then the mandrel could not be got out; the forging then appearing as in [Fig. 2971].
Fig. 2972.
The next process was to put in a bar mandrel such as shown in [Fig. 2972] at i, the pieces j, k fitting on their sides to the mandrel and being curved outside to the circular and taper shape of the hole. The wings e f may then be closed on the mandrel to their proper width and the whole hub end being trimmed by hand, all the previous work having been done under the steam hammer. The hub being finished the key m may be taken out and the washer l taken off, when i can be pulled out, leaving j k to be taken out separately. A pair of tongs are then put through the finished hub end, while the wings are punched and trimmed under the steam hammer, and subsequently finished by hand.