Modern Machine-Shop Practice Part 195

[Ill.u.s.tration: Fig. 2906.]

[Ill.u.s.tration: Fig. 2907.]

The hole for the blank is made about 1/64 inch larger in diameter than the designated size of the bolt, to permit of the easy extraction of the blank after it is upset, this extraction being accomplished by striking the end of the tongue with the hammer. If the block is made of cast iron the upper end of the hole will become worn after forging five hundred or six hundred bolts, leaving the bolts with a rounded neck, as at C C in Fig. 2906; a steel block, however, will forge several thousand bolts without becoming enlarged.

An excellent plan is to provide the block with removable dies, such as at _d_ _d_ in Fig. 2907, which are easily renewed, a number of such dies having different diameters of bore fitted to the same block.

When the bolt end is sufficiently reset or enlarged to form the head it is laid in a bottom swage, containing three of the six sides of the hexagon, and a hammer blow on the uppermost part of the end forges a flat side. After each blow the work is revolved one-sixth of a revolution, and as the angles of the swage are true they obviously true the angles of the bolt head. After the head has been roughed down it is necessary to flatten it again under the head and on the end, for which purpose it may be placed in the heading block shown in Fig. 2904, after which the sides of the head may be finished and the cupping tool for chamfering the head applied.

The bolt may require pa.s.sing from the heading tool to the swage several times, as forging it in one direction spreads it in another.

[Ill.u.s.tration: Fig. 2908.]

In shops where bolt-making is of frequent occurrence a special bolt-making device is usually employed. It consists of an oliver or foot hammer, having two hammers and an anvil; in the square hole at one end of the anvil fits a hardy or bottom chisel, such as shown in Fig. 2908, for cutting up the bar or rod iron into bolt blanks; A is the anvil, H the hardy, and G a gauge to determine the length cut off the rod R to form a blank. An upsetting or heading device corresponding to that in Fig. 2907 is provided, and at the other end of the anvil is the swage for forming the bolt head.

The object of having two hammers is that one may be used for the upsetting of the blank and the other for the swage. The swaging hammer is provided with a hole and set-screw to receive top swages, and bolt hammers are adjustable for height so that they may be set so that their faces will meet the work fair.

[Ill.u.s.tration: Fig. 2909.]

[Ill.u.s.tration: Fig. 2910.]

[Ill.u.s.tration: 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 pa.s.ses 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.

[Ill.u.s.tration: _VOL. II._ =EXAMPLES IN HAND FORGING.= _PLATE XVI._

Fig. 2917.

Fig. 2918.

Fig. 2919.

Fig. 2920.

Fig. 2921.

Fig. 2922.

Fig. 2923.

Fig. 2924.

Fig. 2925.

Fig. 2926.]

[Ill.u.s.tration: Fig. 2912.]

[Ill.u.s.tration: Fig. 2913.]

[Ill.u.s.tration: Fig. 2914.]

[Ill.u.s.tration: Fig. 2915.]

[Ill.u.s.tration: Fig. 2916.]

To forge a turn buckle, such as in Fig. 2912, we bend two rings, such as in Fig. 2913, and weld into the open ends a piece as shown in Fig. 2914, on the opposite side a recess A, Fig. 2915, is cut out to receive a second piece, which being welded in the work appears as in Fig. 2916, and the end may be drawn taper. Two such pieces welded together obviously complete the job.

Fig. 2917 represents a yoke for the slide valve of a steam engine or a locomotive, which may be forged by either of the following methods:

Fig. 2918 represents a stem A welded into the bar B, which may be bent to the required rectangle and welded at the ends.

A second method is to jump the stem D and split it open as in the side view in Fig. 2919. The bar E is forged with a projecting piece to go in the split of D, and after the weld is made, bar E is drawn to size as shown, leaving the two projections _x_ where the corners are to come, which is necessary in order to have sufficient stock to bring the corners up square. The ends of E are split open as in the end view at F, and a piece G is then welded to F.

In a third method the end of the stem is rounded for the weld, as shown in Fig. 2920. The ends of the bar J are then split open and piece K welded on.

It is to be observed with reference to the two last methods that in hammering to forge the weld the frame is closed, so that after welding the swaging to finish may be carried on until the frame is brought to square, and any superfluous metal may be cut away; whereas if the kind of weld is such as to stretch the sides, it may happen that to get a sound weld will stretch the side welded too long and throw the frame out of shape.

Suppose, for example, that a scarf weld were made on the side of the yoke opposite to the stem, and if, in welding, the scarf is hammered too much, it would draw it out too much and throw the whole frame out of shape, as in Fig. 2921, so that the welded side would require to be jumped to bring it back to the proper length again.

A fourth method is to take a piece of iron and punch a hole in it, and then split it open up to the hole, as in Fig. 2922, and by opening out the split form the stem and part of the frame out of the solid, forging the remainder of the frame by the plan described for either the second or third methods.

A fifth method is to make the weld of the stem as in Fig. 2923, then forge out the bar B, leaving projections _x_ _x_ to bring the corners _y_ _y_ up square, and after bending to shape and squaring up to weld in a piece C.

A sixth method is to form the band first as in Fig. 2924, form the stem as in Fig. 2925, and weld as in Fig. 2926.

[Ill.u.s.tration: Fig. 2927.]

[Ill.u.s.tration: Fig. 2928.]

[Ill.u.s.tration: Fig. 2929.]

Figs. 2927, 2928, and 2929 represent a method of forging a fifth wheel for a vehicle. A rectangular piece of Norway iron is fullered to form the recess at C in Fig. 2927. Holes are then punched at _h_ and splits are made to the dotted lines shown in the figure. The ends are then opened out, forming a piece such as in Fig. 2928. The letter A represents the same face of the work in all the figures, being the edge in Fig. 2927, and the top face after the ends are opened out. The four arms may then be dressed to shape, the two lower ones being drawn out and threaded before being finally closed to shape. A piece may then be welded on one end, as at B, to complete the circle.

[Ill.u.s.tration: Fig. 2930.]

[Ill.u.s.tration: Fig. 2931.]

[Ill.u.s.tration: Fig. 2932.]

To forge a double eye, such as in Fig. 2930, we may take a piece of sufficient size and fuller at _a_ _a_, Fig. 2931; a hole is then punched at _b_, and it is then split through to the dotted line in Fig. 2931, and opened out as in Fig. 2932, and then forged to shape.

[Ill.u.s.tration: Fig. 2933.]