mand over it is only limited by our means of applying the requisite force, whether by compression, as in the case of the process of rolling, or by blows, as in the case of forging by the hammer; this latter process being by far the most important, not only in respect to its affording is the means of giving to masses of wrought iron the requisite shape and form, but also, when the process of hammering is carried on with due energy, while the iron is at a welding heat, the effect of such hammering is productive of a most important improvement in the quality of the iron, as regards its tenacity, and consequent capability of resisting strains without the risk of fracture ; this gain of strength arising from the more intimate contact, or union, brought about between the particles of the iron, by reason of the more perfect expulsion of all those impurities which otherwise, by separating the particles, or fibres, of the iron, so impair its strength. Hence we have one of the many important reasons why it is so desirable that we should have the means of hammering iron, when at the proper weld ing heat, with all due energy, whatever be the size, or form, of the mass in question.

The great success which has attended the application of the steam engine in the case of steam ships, and in other instances, has produced a demand for enormous forgings of wrought iron, such as paddle shafts, cranks, &c., that no small difficulty is now felt in the execution of large parts of them, having attained to such a magnitude as to be all but beyond the power and capability of the largest forge hammers to execute them.

The approach of this point of ultimate capability has long been felt, not only by the vast difficulty and expense by the ordinary means, such enormous forgings being so frequently attended by the destruction of the machinery employed, but also by the frequent occurrence of unsoundness being the certain result of inadequate means, and the exceeding the limits and capabilities of the machinery hitherto employed for the purpose, arising from a defect inherent in the principle on which such machinery has been constructed, the evils of which have been rendered more and more apparent by every successive attempt to enlarge the apparatus, with a view to endeavor to enable

to cope with the increase in the magnitude of the forgings it was required to execute.

It was with the view to remove those defects in the principle on which such forge hammers were constructed, and to produce such a hammer as should, in the most simple manner, attain all that was desirable in our means of forging the very largest class of work, and that in a manner infinitely more convenient, perfect, and economical, that led me to contrive my direct action steam hammer, which I shall now proceed to describe, and which has realized my most sanguine expectations of its advantages.

In order to give such of my readers as are not minutely acquainted with the subject, a more clear view of the advantages possessed by this direct action steam hammer over those of forge hammers of the ordinary construction, I must refer them to Fig. 1, which is intended to represent a forge hammer of the largest class, and, generally, ar

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ranged according to the most improved principle. According to the scale on which this sketch is made out, such a hammer would be fully what is called a seven ton hanımer, and, consequently, adapted (so far as its principles of construction will permit) for the execution of the largest class of work.

Fig. 1.- View of the Old Tilting Hammer.

One chief and universal feature in all such hammers is, that the power which causes them to rise and fall, and so give out blows on ihe work on the anvil, consists of rotary motion, which, originating in the rectilinear motion of the piston of the steam engine, is conveyed to the hammer by, and through, the medium of revolving shafts, wheels, &c., and finally re-converted into its original up and down motion by means of the cam wheel, marked D in the sketch; thus, by a very roundabout course, we have brought our power back again into the form it first existed, namely, rectilinear motion, or as nearly so as the radial action of the hammer will permit. And what advantage have we obtained by causing our power to travel to its object by such a roundabout course ? none that I ever could see; and as to the disadvantages, they are many, and most serious. In the first place, there is great loss of power, on account of the very unfavorable manner in which the momentum of the fly-wheel on the cam shaft 1) communicates its motion to the helve of the hammer, by a jolting action most unfavorable to the economical communication of power; add to which the vast space of the forge shop, occupied by all the intermediate apparatus of a complete steam engine, with its requisite fly-wheels,shafts, beams, and very costly foundations, which, in order to endeavor to maintain the apparatus in due order, has to be made of more than ordinary substantiality; so much so, that, to resist the destructive effect of the vibration given to the entire machinery by the action of the hammer, the foundations have to be made so solid as to cost, in some cases, nearly as much as the whole metallic part of the apparatus.

With respect to the action of such a forge hammer, as seen in Fig. 1, it will be found that one grand defect in principle exists, namely, that, when engaged in hammering a large piece of work, as that seen in the sketch, by reason of the work occupying the greater part of the clear space between the anvil face and that of the hammer, we have thereby a slight blow when we are doing a large piece of work, and a heavy blow when we are hammering a small, or thinner, piece of work, which is just the very reverse of what we could desire., And, in the execution of large work, this is found to be a most serious evil, inasmuch as, from the nature of the case, we would wish to have the most powerful and energetic blows that it is possible to command. The result of this is, that neither is the mass rendered so sound as we could desire, nor is it brought to its required form except by repeated heatings, at the very great sacrifice of time and iron, in so far as, ere the limited blows of the hammer have produced the required change of form, the welding heat has gone off, and all blows after this tend rather to loosen, than compact, or solidify, the mass. Again, we have another very serious evil, namely, the very confined limits of the space between the hammer face at its highest, and that of the face of the anvil, which renders it quite incapable of admitting, or operating upon, a mass of any great breadth, or height; and besides having the machinery of the hammer quite in the way, in many cases we have also this other disadvantage, namely, that, except for one thickness of work, the hammer face and anvil are not parallel, as will be evident on referring to the sketch, and considering that the face of the hammer acts radial to the centre, S, Fig. 1, in which it rocks. This evil is, to a small extent, obviated by means being given to raise up the tail, or centre, S; but this process is not only difficult, but can only be done between the heats.

With a view to relieve all these defects, I have contrived my direct action steam hammer, which is represented, in one of its many formis and applications, in Fig. 2.

It consists simply of a cylinder, C, turned, as it were, upside down; that is, its piston rod comes out at the bottom of the cylinder, instead of (as in most cases) out of the top; this cylinder is supported over the anvil K by two upright standards, 0 0, the end of the piston rod being attached to a block, or mass, of cast iron, B, guided in its descent by planed guides, or ribs, cast on the edge of each standard. This block of cast iron is the hammer, or blow-giving part of the apparatus, while the cylinder, with its piston and piston-rod, supplies in the most simple, straightforward, and direct manner, the power by which the striking block, B, is lifted, or raised up. Gravity performs the down

, ward action for us in a most direct manner. In order to set this steam hammer in action, steam of such a pressure as, operating upon the under side of the piston, will a little* more than balance the weight of the block, B, is conveyed from a suitable boiler, (situated in any convenient part of the premises,) through the pipe, P, into the valve box, in which a slide valve of the most simple form works. The valve, being up, permits the steam to press upon the under side of the piston, and up goes the block, B, to any height (within the limits

• About five to six per cent. more pressure than will just balance the block, gives all due activity to the upward, or lifting, action of the block.

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of the length of the cylinder) which the forge man may require. The handle, E, is now moved in the contrary direction, which not only prevents any further admission of steam, but also permits that which had entered to escape by the pipe, L; the instant this is done, the block B descends with all the energy and force due to its weight and the height through which it falls, and discharges its full and entire momentum upon the work then on the anvil, with such tremendous effect as to set the blows of all previous hammers at utter defiance ! In fact, the power of such a hammer is only limited by the size we please to make it, as the principle is capable of being carried out to any extent; whereas, in the case of such hammers as in Fig. 1, they have their limits, by reason of the very mass of material causing them to be weak per se, by the intestinal contraction of the iron which composes their mass, and which, in their action, is so destructive and trying to such a form; the consequence is, they generally break over just behind the neck.

Fig. 2.—Nasmyth's Direct Action Steam Hammer.

I have only alluded to the means which this steam hammer gives of obtaining tremendous blows. But, energetic and powerful as it is, it is at the same time one of the most striking examples of the manageability of the power of steam; inasmuch as, when we desire to

Vol. V, 3RD SERIES. No. 3.–Marca, 1843.

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have any variety in the intensity of the blow, varying from the most gentle nut-cracking tap! to the most awful smash, we have simply to work the valve-handle in proportion, and, by so regulating the exit of the steam, we can let down the block, like closing a well-hung window, or arrest its downward progress in an instant at any part of its stroke, and retain it there at any required height, for any required time; on the other hand, by duly regulating the entrance of the steam, we can lift the block to any required height from the face of the anvil, or surface of the work, and so regulate the amount, or rapidity, of the blows accordingly.

The form and arrangement of the steam hammer, as given in Fig. 2, is such as present experience shows to be most convenient; according to the scale on which the sketch is made out, the distance between the standards ( 0 gives a clear space of twelve feet, namely, six feet on each side of the centre of the anvil, and six feet height clear over head, as figured in the sketch. But these proportions may of course be varied at will, as the principle of this steam hammer affords every facility to extension, or otherwise. The space on each side of the anvil, in front and behind, being quite clear of all machinery, gives every facility to the introduction and management of the work, when we progress, as will be evident to, and fully appreciated by, practical men.

The comparatively small space which the entire apparatus of the steam hammer occupies, may be judged of by a glance at the sketch, Fig. 2, as compared with that of the ordinary construction in Fig. 1. Had I turned the standards in the sketch, Fig. 2, so as to give a side, or edge, view, the contrast in respect to space occupied would have been much more striking. As regards the comparative original cost, any one the least accustomed to such matters will at once see the vast advantage, in that respect, in favor of the steam hammer, to say nothing of its vast superiority as to efficiency and little liability to derangement; in fact, so simple is it, that there is scarcely anything to go wrong. One great source of its durability in this respect is the manner in which the mass of the block is raised, namely, through the medium of the most elastic of all bodies_steam; which, in place of any destructive jerk, as in the case of motion conveyed by impulse through solid media, so apparent and destructive in its effect in the case of the apparatus of the ordinary forge hammer, with the steam hammer the lifting motion is performed so smoothly as to be absolutely silent in its action, as if the great block had forgot, for the while, that it had any weight at all. I do not intend here to rival the celebrated Caterfelto by wondering at my own wonders ! but, truly, the action of this simple, but most powerful, machine is not a little striking, both in its action as well as effect. I think experience will prove that I am not too far yielding to sanguine expectations when I state that the vast facilities which this invention gives to the treatment of large masses of wrought iron, will introduce quite a new era in the manufacture and working of wrought iron. We have now, by means of this steam hammer, a power and capability of producing forgings of wrought iron, of any dimensions, whose soundness will

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