Fig. 2911.
[Figs. 2909] to [2911] represent front, side, and top views of Pratt & Whitney’s portable bolt-forging device. It is provided with an elevating screw that permits the employment of a single bolster-pin for all lengths of bolt for a given diameter, instead of requiring a separate pin for each different length of bolt. In the figures, a is a frame carried upon wheels, and to which is pivoted at c c the jaw d. The bolt-gripping dies are shown at e f. A treadle g is pivoted at h, and acts upon the lower end of d, causing the die f to grip or release the bolts, as may be required. The bolster-pin rests upon the end of the screw i, which enters at its foot a split nut j, which is caused to grip and lock the screw by operating the nut of the bolt k that passes through the split of the nut. l is a spring that lifts the treadle when it is relieved of the pressure of the operator’s foot.
At m is a leather washer to protect the nut j from the scale that falls from the forging. The operation is as follows:—
The nut k is released and the screw i operated to suit the length of bolt required. Then j is caused to clamp the screw by operating the nut k. The blank for the bolt is placed in the dies resting on the bolster-pin, which in turn rests upon the end of the screw i. The treadle g is depressed, and the bolt blank clamped between e and f. The helper then with the sledge upsets the blank end to form the bolt head, and the blacksmith forges it to shape in the former bar b, which is provided with impressions for the form of head required, these impressions being of varying sizes, as shown. The device is so strongly proportioned as to be very solid, and is found to be a most useful addition to the blacksmith’s shop.
Fig. 2912.
Fig. 2913.