In the present case the ingot is drawn down by a 35-ton duplex hammer to a slab 24« inches by 12 inches, Figs. 219 and 220, and immediately brought to the hot saw, and sawn as indicated by Fig. 219, for the sweeps. It is finished at an 8-ton vertical hammer, the first operation being to cut out the gusset A, Fig. 219, with a large cutter, and then roughly round up this end to 9« inches diameter. The portion between the sweeps is then removed by cutters, the staff changed, re-heated, and the gusset B, Fig. 219, cut out, and this end roughly rounded to 9« inches diameter. The hammer blocks are then changed for a narrower set, so that the middle can be rounded roughly, and then re-heated for twisting, right-hand sweep to lead. The sweep that follows is then placed between the anvil and tup, and the leading sweep has a large spanner attached. It is then drawn up at right angles by suitable means, utilising hydraulic or any other available power.

Fig. 219.

Fig. 220.

For obvious reasons, the leading sweep is the one always twisted, as it will then always precede, whether in forward or backward gear. The middle is then hammered to "peg," the finished forge size being 8 inches diameter, and the blocks changed for the ordinary set. The ends are then finished exactly to 9« inches diameter, forge size, utilising a peg, and cut to length, each end resting in turn upon a swage to preserve its symmetry, and ordinary cutting tools are used. The sweeps are then rounded under the hammer, top and bottom, and if found to be of slightly insufficient width, a fuller, consisting of a round bar, is stamped down the centre, which widens them out, without affecting the thickness where it is required. The finished forging is shown in Figs. 221 and 222, but minus this groove.

It may be here observed that all the following forgings are manufactured front a mild steel of similar quality to that of crank axles, the exceptions being noted where necessary. In every case their utility and durability depend to a greater extent upon their ductility, than a high tenacity. They are subjected to such stress and strain in everyday working, that a high tenacity would be absolutely detrimental to an economical life, and to the safety of the travelling public. When necessary they are lined with case-hardened bushes or faces, that is, where great wear and tear take place locally. The crank pins for the outside rods are forged as indicated by Figs. 223 and 224; three or four continuously, that is, in one length of bar, as shown, and afterwards sawn off. Blooms are roughed out to 5 inches square, and about 3 feet 6 inches long, and the pins are swaged out to the required size by a pair of fast hammer blocks, no other tools being required, The washers for these pins are stamped in a loose die, from round bars 3 inches diameter cut to a length of 6 inches, the hole being punched through a guide plate, Fig. 225.

Fig. 221.

Fig. 222.

Fig. 223.

Fig. 224.

The specified tensile tests for engine straight axles are the same as for crank axles, besides which they must withstand sixteen blows from a 1-ton tup falling 25 feet, resting upon centres 3 feet 9 inches apart, after each blow the axle being turned and the test continued until fracture, generally requiring to be nicked. The deflection will of course fluctuate according to the temper of the material, but as the percentage of carbon will only vary a few points - hundredths per cent. - it follows that the deflection is generally found to be fairly constant, that for engine axles being about 1« to 1¾ inch, and tender axles from 3 to 5 inches for each blow, and becoming straight, or nearly so, upon reversal. The heat developed in these tests is very considerable, but the author has known an engine axle with a deflection of nearly 5 inches to be straightened by blows from the tup falling 25 feet, after remaining in its deformed condition for four days, without being annealed. Within the specified tenacity, 26 and 28 per cent, elongation is obtained both on the length and crossway samples, and from 40 to 60 per cent, contraction of area. They are made from blooms 4 feet 9 inches long, 9« inches square, with round corners, at a 5-ton hammer, One end is rounded to a peg 9 inches in diameter, and cut off in swages, then the neck and collar are stamped in a pair of swages as indicated by Fig. 226, the middle being hammered to peg, leaving about ¬ inch all over for turning.

Fig. 225.

Fig. 226.

In some works the blooms are rolled to the rough section here shown in a cogging mill, and in all cases the axles are swaged at two heats, one half of each axle being finished before the other half is commenced, either by the swages as shown, or fast hammer blocks, this being the most rapid and economical way of forging them. The coupling rods are forged from a slab 12 by 4« inches by 3 feet 1 inch, the middle being first drawn down to pegs 4¾ by 2 inches, then the bosses for the pins are stamped in a pair of swages. Fig. 227, the whole job being finished and set for the machine shop without any further trimming up in the smithy. The following sketches. Fig. 227a, clearly show the operation of punching these rods; F is a plan of the block D, which is a steel casting, and G is a sectional elevation upon A B, also giving another view of the rod, shown in Fig. 227. The rod is forged slightly smaller thar the block and a little thicker than required, the latter being of exact forge size, so that during punching the forging swells, although slightly drawn in at the top, and fits the block exactly; and this necessitates the loose block E to facilitate the removal of the rod, which operation is obvious. The connecting-rods are forged in pairs; that is, two big ends are forged in one piece, and after the rods are finished they are divided at the big ends, the tools used being simply the peg, plate, and the swages for the enlargement for the Joy motion pin. After hammering down the big ends to peg, the radius A, Figs. 228 and 229, is formed by the hammer blocks.