Necessity of blending steel and iron.-Damascus steel.

thickened, and, while one end rests upon the anvil, hammering at the other till the required size is produced.

In forging steel, great care must be taken not to use a higher degree of heat than is absolutely necessary to effect the desired purpose, as well as to use the fewest heats possible. To unite steel to iron completely, without injuring the former, is an operation that demands a nicety of management which workmen are not often very anxious to display. Those, therefore, whose purposes require it to be well performed, will only employ men on whom they can depend. It is not always merely for economy, that steel is welded to iron, but often principally with the view of uniting the opposite qualities of the metal in each state. If the mandrel of a lathe were made of the best steel, sufficiently hard to wear well in the collar, it would be snapped by a sudden check: and an axe, wholly of steel, if soft, would be useless; and if hard, would probably neither bear the shock of a violent blow, nor the twisting to which such tools are subjected. But by uniting a proper quantity of iron with the steel, the inconvenience, and even danger, resulting from such accidents, are avoided. In applying them to each other, regard must be paid to the manner in which the tool will be used. For an axe, the edge of which is formed by grinding both sides, the steel is placed in the middle, between two plates of iron; the blade of a plane, which is ground only on one side, requires the iron also to be only on one side, namely, the back of it; and for that part of a mandrel which works in the collar of a lathe, the steel must encircle the iron.

Damascus was anciently famed for the excellence of the steel goods manufactured there, especially its swords, which are said to possess all the advantages of flexibility, elasticity, and hardness. These united distinctions are supposed to have been effected by blending alternate portions of iron and steel; the latter, by repeatedly drawing out, doubling, and welding the work, being diffused throughout the former, almost as completely as a drop of ink is diffused, by intermixture, with a glass of water. But the best attempt which we are at present aware of having been made in England, to imitate Damascus steel, according to the plan here pointed out, did not perfectly succeed, the mass produced having cracked in tempering. It appears pro bable, that the desired imitation may be effected with much greater advantage by the use of steel alone, the iron from which it is made being judiciously selected, and afterwards very care fully cemented and forged. It is Swedish iron that is mostly converted into steel; but that kind called old sable (which, we believe, comes from Russia,) possesses, in point of tenacity, ac

Walby's forge hammer.-Welding cast steel.

cording to the experiments of an ingenious philosopher, a very decided superiority over every other kind. It would, doubtless, therefore, be suitable for the purpose; the properties of steel being influenced, as will easily be supposed, by the properties of the iron from which it is manufactured: and, in confir mation of what has been said of the advantages of good forging, we may here take notice of the forge hammer, invented by George Walby, of London, for which invention, the Society for the Encouragement of Arts, &c. rewarded him with their silver medal and forty guineas. Although it weighs seventy pounds, it may be wrought by one man, with the greatest accuracy and ease, at the rate of three hundred blows per minute, and performs the work of two or three men. The inventor states to the Society, that the steel is kept in better temper by this hammer, and fewer heats are required for the same work, than in the common way; that the trowels made with it by him, will bear any pressure of bending, and return by their elasticity to their original shape, and they will even cut a chip from a bar of iron, without hurting their edge; they also are lighter and more handy than common trowels, and serve much longer in use.

The steel which contains the smallest proportion of carbon, as, for example, shear steel, is the most easily welded; but it is by fusion, which entirely destroys its fibrous texture, that it is rendered incapable of being welded to itself, and some maintain that genuine cast steel has never been united even to iron by welding. Yet others have stated, that the means by which this may be accomplished, consist in placing between the iron and the steel another kind of steel, in the form of filings, or a thin plate, the iron being brought to a welding heat, and the cast steel made as hot as can be done with safety. Such, however, are the difficulties of the operation, and so frequently imperfect the work when finished, that other means of effecting the union have been resorted to. One of them, for which a patent has been granted, has been brought into common use, for the blades of joiners' planes, and many other purposes; it consists in uniting the steel to the iron with soft solder or tin. In this process, the cast steel, not being exposed to much heat, loses none of its good properties, but the union is not so substantial as that afforded. by welding.

For the description of this hammer, illustrated by an engraving, see the Transactions of the Society for the Encouragement of Arts, Manufactures and Commerce, or the Repertory of Arts, vol. 7, second series, 1805.

The forge bellows.-The anvil.—The vice.

Of the Tools used in forging Iron, and in the working of Metals generally.

Minutely to describe the various tools made use of in forging iron, and in the working of metals generally, would be more likely to tire than to please our readers, to whose information on such points, a volume of the most elaborate description, would not add so much, as a few moments' inspection of workshops which may be seen in every village of the kingdom. We shall, therefore, on this, as on other occasions of the kind, confine our remarks to particulars which are, for the most part, either not generally practised, or not often communicated by workmen, or not the most likely to catch the eye of the looker-on.

The best position for the bellows is on a level with the fireplace, but they are frequently placed higher, and the blast communicated through a bent tube, for the purpose of gaining room near the floor. The small end of the pipe of the bellows passes through the back of the forge, where it is fixed in a strong iron plate, called a tue iron, or patent back, in order to preserve the bellows from injury, and the back of the forge from requiring frequent repair.

The anvil is a substantial mass of iron, to the surface of which a plate of steel is firmly welded, and made sufficiently hard to withstand the file, or the blow of a hammer. It is usu ally made, for forging iron upon, with one or two projecting arms, and is then called a beak iron. These arms are useful in giving the requisite form to various sorts of work: when there is only one, it is preferred of a conical shape; when there are two, one of them is pyramidical. They are affixed lengthways, a little below the surface of the body of the anvil, and rather inclining upwards towards the point. In Birmingham, where attic rooms are frequently converted into workshops, the block upon which the anvil is fixed, is placed upon a stratum of sand, which prevents the vibrations that would otherwise be communicated to the floor, and much of the noise which would incommode the inhabitants of the room below. The contrivance is simple, and susceptible of other applications. Clock-makers use very small anvils or beak irons, which they fix in the vice when in use. The anvils of tin-plate workers are of various sizes, and are often made with concavites and projections upon them, by the help of which they can readily communicate different shapes to their work.

The large vice must be firmly fixed to the side of the workbench, to the edge of which its chaps must be parallel, their

Hand vice.-Hammers.

The

upper surface being at the same time exactly horizontal. best elevation for a vice, is that of the workman's elbow, when the upper arm is held vertically against the side; and the lower arm, for the sake of trying the height, is held at right angles thereto. In filing, if the vice or the work be above this position, which is seldom heeded, or even thought of, the stroke will not be so powerful as the same exertion would otherwise make it; and, whether higher or lower, it will be found exceedingly difficult to carry the file in a horizontal direction. As the teeth on the inner surface of the chaps would mar fine work, if pressed against it sufficiently hard to keep it steady, they are, as often as the occasion requires, covered with plates of lead, about the eighth of an inch thick. These plates must be large enough to extend about half an inch on each side beyond, and an inch above the chaps, to each of which, when screwed tight, one of them is secured by hammering down the projecting parts.

The hand rice is used to hold small articles in the act of filing; it is held in the left hand, and the parts of the iron, while pressed upon the end of the bench, or upon a bit of wood or bone in the large vice, is successively turned to the file, which is held in the right hand. A nick is made in the wood or bone, to keep the work from being carried aside by the file.

Hammers, like anvils, are faced with steel, in a state of considerable hardness. Their handles are almost always made of nearly a uniform thickness in every part, or if they differ from such figure, it is not for any specific purpose. Hence the vibrations of the hammer head are communicated to the hand, to which they occasion very unpleasant sensations, and the workman is tired before he has much exerted his strength. If the handle of the hammer, at a little distance from its upper end, be made considerably smaller, for a short space, than in any other part, the alteration will be found a decisive improvement. Such a ham. mer will, as it is technically termed, fall well, diminishing, at the same time, the workman's fatigue, and convincing him that his blows are solid and effectual. Fig. 1. pl. III. will clearly designate this construction; it represents a hammer for chipping iron; for which purpose, the head need not be more than sixteen ounces in weight, and the handle about twelve inches long. a hammer of any given shape, calculated to give the hardest blows with the least weight, and, consequently, with the least fatigue, the quantity of iron in the head should be equal on the opposite sides of a line supposed to be drawn perpendicular to the centre of the face. Hammers, therefore, made for the purpose of drawing nails, with claws, which lean backwards from

In

Rivetting.-Cutting metals with shears-chisels-saws.

this line, are not calculated to produce the best effect in striking. Clockmakers, tin-plate workers, and braziers, polish the face of their planishing hammers, by rubbing them upon a soft board, covered with a mixture of oil and finely washed emery. Watchmakers and silversmiths take still more pains with theirs, selecting them free from every flaw, removing every scratch, and giving them an exquisite lustre with colcothar or putty. These various artists, also, for their respective purposes, require them to be made of a numberless variety of shapes, convex, concave, cylindrical, &c.

In rivetting two pieces of metal together, if the head of the rivet is not intended to project, the hole must be widened a little at the top and bottom. One of the heads of a rivet should be made before it is put into its place, in which it is secured, by striking the edge of the other end of the shank (previously filed flat) with light blows, till it is evenly spread all round, when heavier blows may be used, till it is sufficiently firm. When the head of a rivet or screw is on a level with the surface of the work, it is said to be countersunk.

In cutting sheet iron or brass, and even bars of the same metals, shears are used. They are frequently made three or four feet long; one handle is screwed fast in the vice, or secured to the bench, and the uppermost only is moveable. The harder the work they have to do, the more obtuse the angle by which the edge is formed. A chisel is often used instead of a pair of shears, and though it does not cut with so much rapidity, it is, on many occasions, more convenient, as it can be made of dif ferent figures, guided in various directions, and stopped at any given point. Plates of metal to be cut with a chisel, are laid, during the operation, upon a mass of lead, or upon an anvil; if the latter be used, they are not cut quite through, to prevent injuring the chisel, yet they are so nearly divided that the sepa ration can be effected by striking them with the hammer white held on the edge of the anvil, or by wriggling them with the hand or in the vice.

Saws for cutting metals, are made very narrow, (see fig. 2. pl. III:) and stretched by a screw at one end; they are, in ge neral, rather thicker on the edge than at the back; the teeth are small, and are not bent like those for joiners' use. Clock and watch makers often make their saws of broken watch-springs, the temper of which is suitable for the purpose, and the metal com monly excellent. In sawing malleable iron and steel, oil must be used; crude iron and brass require no oil, but for the latter, a very sharp saw is necessary, and it may also be rather harder than for iron.

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