Popular Technology Volume II Part 22

3. The finer kinds of wire are made from the larger by repeated drawings, each of which is performed through a smaller hole than the preceding. As the metal becomes stiff and hard, by the repet.i.tion of this process, it is occasionally annealed, to restore its ductility.

Wire is formed of other metals by the same general method.

THE STEEL MANUFACTURER.

1. Steel is a compound of iron and carbon; and, as there are several methods by which the combination is produced, there are likewise several kinds of steel. The best steel is said to be made of Swedish or Russian bar-iron.

2. The most common method of forming steel is by the process of _cementation_. The operation is performed in a conical furnace, in which are two large cases or troughs, made of fire-brick, or good fire stone; and beneath these is a long grate. On the bottom of the cases is placed a layer of charcoal dust, and over this a layer of bar-iron.

Alternate strata of these materials are continued to a considerable height, ten or twelve tons of iron being put in at once.

3. The whole is covered with clay or sand, to exclude the air, and flues are carried through the pile from the furnace below, so as to heat the contents equally and completely. The fire is kindled in the grate, and continued for eight or ten days, during which time, the troughs, with their contents, are kept red hot. The progress of the cementation is discovered by drawing a _test_ bar from an aperture in the side.

4. When the conversion of the iron into steel appears to be complete, the fire is extinguished; and, after having been suffered to cool for six or eight days, it is removed. Iron combined with charcoal in this manner, is denominated _blistered steel_, from the blisters which appear on its surface, and in this state, it is much used for common purposes.

5. To render this kind of steel more perfect, the bars are heated to redness, and then drawn out into bars of much smaller dimensions, by means of a hammer moved by water or steam power. This instrument is called a tilting hammer, and the bars formed by it, are called _tilted steel_. When the bars have been exposed to heat, and afterwards doubled, drawn out, and welded, the product is called _shear steel_.

6. But steel of cementation, however carefully made, is never quite equable in its texture. Steel possessing this latter quality is made, by fusing bars of blistered steel, in a crucible placed in a wind furnace. When the fusion has been completed, the liquid metal is cast into small bars or ingots, which are known in commerce by the name of _cast steel_. Cast steel is harder, more elastic, closer in texture, and capable of receiving a higher polish than common steel.

7. Steel is also made directly from cast iron, or at once from the ore. This kind is called _natural_ or _German_ steel, and is much inferior to that obtained by cementation. The best steel, produced directly from the ore, comes from Germany, and is made in Stiria. It is usually imported in barrels, or in chests about three feet long.

8. Steel is sometimes alloyed with other metals. A celebrated Indian steel, called _wootz_, is supposed to be carbonated iron, combined with small quant.i.ties of silicium and aluminum. Steel alloyed with a very small proportion of silver, is superior to wootz, or to the best cast steel. Some other metals are also used with advantage in the same application.

9. Steel was discovered at a very early period of the world, for aught we know, long before the flood. Pliny informs us, that, in his time, the best steel came from China, and that the next best came from Parthia. A manufactory of steel existed in Sweden as early as 1340 of the Christian era: but it is generally thought, that the process of converting iron into steel by cementation originated in England, at a later period. The method of making cast steel was invented at Sheffield, in the latter country, in 1750, and, for a long time, it was kept secret.

10. It has been but a few years, since this manufacture was commenced in the United Sates. In 1836, we had fourteen steel furnaces, viz.; at Boston, one; New-York, three; Troy, one; New-Jersey, two; Philadelphia, three; York Co., Pa., one; Baltimore, one; and Pittsburg, two. These furnaces together are said to be capable of yielding more than 1600 tons of steel in a year. The American steel is employed in the fabrication of agricultural utensils, and it has entirely excluded the common English blistered steel.

[Ill.u.s.tration: BLACKSMITH.]

THE BLACKSMITH, AND THE NAILER.

THE BLACKSMITH.

1. The blacksmith operates in wrought iron and steel, and, from these materials, he fabricates a great variety of articles, essential to domestic convenience, and to the arts generally.

2. This business is one of those trades essential in the rudest state of society. Even the American Indians are so sensible of its importance, that they cause to be inserted in the treaties which they make with the United States, an article stipulating for a blacksmith to be settled among them, and for a supply of iron.

3. The utility of this trade will be further manifest by the consideration, that almost every other business is carried on by its aid. The agriculturist is dependent on it for forming utensils, and mechanics and artists of every description, for the tools with which they operate; in short, we can scarcely fix upon a single utensil, vehicle, or instrument, which does not owe its origin, either directly or indirectly, to the blacksmith.

4. This business being thus extensive in its application, it cannot be presumed that any one person can be capable of executing every species of work. This, however, is not necessary, since the demand for particular articles is frequently so great, that the whole attention may be directed to the multiplication of individuals of the same kind.

Some smiths make only anchors, axes, scythes, hoes, or shovels.

5. In such cases, the workmen acquire great skill and expedition in the manufacture. A tilt hammer is often used in forging large ma.s.ses of iron, and even in making utensils as small as the hoe, the axe, and the sword; but the hammer which may be employed bears a due proportion in its weight to the ma.s.s of iron to be wrought. In all cases in which a tilt hammer is used, the bellows from which the blast proceeds is moved by water or steam power.

6. In the shop represented at the head of this article, sledges and hammers are used as forging instruments, and these are wielded by the workmen themselves. The head workman has hold of a piece of iron with a pair of tongs, and he, with a hammer, and two others, with each a sledge, are forging it upon an anvil. The two men are guided in their disposition of the strokes chiefly by the hammer of the master-workman.

7. In ordinary blacksmith shops, two persons commonly work at one forge, one of whom takes the lead in the operations, and the other works the bellows, and uses the sledge. From the part which the latter takes in the labor, he is called the _blower_ and _striker_. A man or youth, who understands but little of the business, can, in many cases, act in this capacity tolerably well.

8. The iron is rendered malleable by heating it with charcoal or with stone coal, which is ignited intensely by means of a blast from a bellows. The iron is heated more or less, according to the particular object of the workman. When he wishes to reduce it into form, he raises it to a _white heat_. The _welding heat_ is less intense, and is used when two pieces are to be united by _welding_. At a red heat, and at lower temperatures, the iron is rendered more compact in its internal texture, and more smooth upon its surface.

9. The joint action of the heat and air, while the temperature is rising, tends to produce a rapid oxydation of the surface. This result is measurably prevented by immersing the iron in sand and common salt, which, uniting, form a vitreous coating for its protection. This coating is no inconvenience in the forging, as its fluidity causes it to escape immediately under the action of the hammer.

10. Steel is combined with iron in the manufacture of cutting instruments, and other implements, as well as articles requiring, at certain parts, a great degree of hardness. This substance possesses the remarkable property of changing its degree of hardness by the influence of certain degrees of temperature. No other substance is known to possess this property; but it is the peculiar treatment which it receives from the workman that renders it available.

11. If steel is heated to redness, and suddenly plunged into cold water, it is rendered extremely hard, but, at the same time, too brittle for use. On the other hand, if it is suffered to cool gradually, it becomes too soft and ductile. The great object of the operator is to give to the steel a quality equally distant from brittleness and ductility. The treatment by which this is effected is called _tempering_, which will be more particularly treated in the article on the cutler, whose employment is a refined branch of this business.

THE NAILER.

1. Nail-making const.i.tutes an extensive branch of the iron business, as vast quant.i.ties of nails are annually required by all civilized communities. They are divided into two cla.s.ses, the names of which indicate the particular manner in which they are manufactured; viz., _wrought nails_ and _cut nails_.

2. The former are usually forged on the anvil, and when a finished head is required, as is commonly the case, it is hammered on the larger end, after it has been inserted into a hole of an instrument formed for the purpose. Workmen by practice acquire surprising dispatch in this business; and this circ.u.mstance has prevented the general introduction of the machines which have been invented for making nails of this description. Wrought nails can be easily distinguished from cut nails, by the indentations of the hammer which have been left upon them.

3. In making cut nails, the iron is first brought into bars between grooved rollers. The size of the bars is varied in conformity with that of the proposed nails. These bars are again heated, and pa.s.sed between smooth rollers, which soon spread them into thin strips of suitable width and thickness. These strips, having been cut into pieces two or three feet in length, are heated to a red heat in a furnace, to be immediately converted into nails, when designed for those of a large size. For small nails, the iron does not require heating.

4. The end of the plate is presented to the machine by the workman, who turns the material over, first one way and then the other; and at each turn a nail is produced. The machine has a rapid reciprocating motion, and cuts off, at every stroke, a wedge-like piece of iron, const.i.tuting a nail without a head. This is immediately caught near the head, and compressed between _gripes_; and, at the same time, a force is applied to a die at the end, which spreads the iron sufficiently to form the head. From one to two hundred can be thus formed in a minute. This fact accounts for the low rate at which cut nails are now sold, which, on an average, is not more than two cents per pound above that of bar iron.

5. On account of the greater expense of manufacturing wrought nails, they are sold much higher. It is said that nine-tenths of all the nails of this kind, used in the United States, are imported from Europe. We thus depend upon foreign countries for these and many other articles, because they can be imported cheaper than we can make them; and this circ.u.mstance arises chiefly from the difference in the price of labor.

6. The first machine for making cut nails was invented in Ma.s.sachusetts about the year 1816, by a Mr. Odion, and soon afterwards another was contrived, by a Mr. Reed, of the same state. Other machines, for the same purpose, have likewise been constructed by different persons, but those by Odion and Reed are most commonly used.

Before these machines were introduced, the strips of iron just described, were cut into wedgelike pieces by an instrument which acted on the principle of the shears; and these were afterwards headed, one by one, with a hammer in a vice. The fact, that the manufacture of this kind of nails originated in our country, is worthy of recollection.

7. In 1841, Walter Hunt, of New-York, invented a double reciprocating nail engine, which is owned by the New-York Patent Nail Company. This machine works with surprising rapidity, it being capable of cutting five or six hundred ten-penny nails in a minute. One hand can tend three engines, as he has nothing more to do than to place the heated plate in a perpendicular position in the machine.

8. This manufacture includes, also, that of tacks and spikes; but since, in the production of these, the same general methods are pursued, they need no particular notice. The different sizes of tacks are distinguished by a method which indicates the number per ounce; as two, three, or four hundred per ounce. Spikes are designated by their length in inches, and nails by the terms, two-penny, three-penny, four-penny, ten-penny, and so on up to sixty-penny.

[Ill.u.s.tration: CUTLER.]

THE CUTLER.

1. Under the head of cutlery, is comprehended a great variety of instruments designed for cutting and penetration, and the business of fabricating them is divided into a great number of branches. Some manufacture nothing but axes; others make plane-irons and chisels, augers, saws, or carvers' tools. Others, again, make smaller instruments, such as table-knives, forks, pen-knives, scissors, and razors. There are also cutlers who manufacture nothing but surgical instruments.

2. The coa.r.s.er kinds of cutlery are made of blistered steel welded to iron. Tools of a better quality are made of shear steel, while the sharpest and most delicate instruments are formed of cast steel. The several processes const.i.tuting this business may be comprised in forging, tempering, and polis.h.i.+ng; and these are performed in the order in which they are here mentioned.

3. The general method of _forging_ iron and steel, in every branch of this business, is the same with that used in the common blacksmith's shop, for more ordinary purposes. The process, however, is somewhat varied, to suit the particular form of the object to be fas.h.i.+oned; for example, the blades and some other parts of the scissors are formed by hammering the steel upon indented surfaces called _bosses_. The bows, which receive the finger and thumb, are made by first punching a hole in the metal, and then enlarging it by the aid of a tool called a _beak-iron_.

4. The steel, after having been forged, is soft, like iron, and to give it the requisite degree of strength under the uses to which the tools or instruments are to be exposed, it is hardened. The process by which this is effected is called _tempering_, and the degree of hardness or strength to which the steel is brought is called its _temper_, which is required to be _higher_ or _lower_, according to the use which is to be made of the particular instrument.

5. In giving to the different kinds of instruments the requisite temper, they are first heated to redness, and then plunged into cold water. This, however, raises the temper too high, and, if left in this condition, they would be too brittle for use. To bring them to a proper state, they are heated to a less degree of temperature, and again plunged into cold water. The degree to which they are heated, the second time, is varied according to the hardness required. That this particular point may be perfectly understood, a few examples will be given.

6. Lancets are raised to 430 degrees Fahrenheit. The temperature is indicated by a pale color, slightly inclined to yellow. At 450 degrees, a pale straw-color appears, which is found suitable for the best razors and surgical instruments. At 470 degrees, a full color is produced, which is suitable for pen-knives, common razors, &c. At 490, a brown color appears, which is the indication of a temper proper for shears, scissors, garden hoes, and chisels intended for cutting cold iron.