William L. Ilgen

“ Figure 42 shows a sectional view of a blacksmithing fire: d is the bed of hot coke; c is the dampened and unburned coal which surrounds the fire, continually forming more coke as it is needed and also holding the fire in a compact form; a shows the proper way of placing the metal in the fire, b, the improper way because the metal is too near the entrance of the blast. As heating is such an important operation, a thorough understanding of what causes imperfect heats, as well as how to prevent them, is necessary. ”

“ The Hammers.—Of the multitude of tools used by mechanics, the hammer is undoubtedly the most important one. There was a time when man had only his hands to work with, and from them he must have received his ideas for tools. Three prominent ones which are used extensively at present were most probably imitations of the human hand. From the act of grasping, man could easily have originated the vise or tongs for holding materials that he could not hold with the hand. ”

“ When a piece of metal is to be drawn to a smaller dimension, with shoulders opposite each other, on either two or four sides, these blows will produce the required result to the best advantage. They are more effective if the metal is held at a slight angle across the edge of the anvil face, but then the hammer blows must be delivered a little beyond the anvil edge, so that the upper and lower depressions in the metal will be formed exactly opposite each other, as shown at b, where the depressions are indicated by the broken lines. ”

“ The value of limestone as a flux depends upon its freedom from impurities, such as silicon and sulphur.
Sulphur and phosphorus are two elements which must be kept out of the product. When there is too much sulphur, the iron is exceedingly brittle at a dull red heat, although it can be worked at a higher or lower temperature. It is called red-short iron and makes welding difficult. With steel, sulphur diminishes the tensile strength and ductility. If there is too much phosphorus combined with iron, the metal will crack when hammered cold. ”

“ Coke is used mostly in furnaces or when heavy pieces of metal are to be heated. It is a solid fuel made by subjecting bituminous coal to heat in an oven until the gases are all driven out.
Charcoal is the best fuel, because it is almost free from impurities. The most satisfactory charcoal for forging purposes is made from maple or other hard woods. It is a very desirable fuel for heating carbon steel, because it has a tendency to impart carbon instead of withdrawing it as the other fuels do to a small extent. ”

“ The cold cutter B is forged considerably heavier on the cutting end than is the hot cutter, in order to give it plenty of backing to withstand the heavy blows that it receives. The cutting edge is ground convex to prevent the possibility of the corners breaking off easily, and is ground more blunt than the hot cutter. It should be used only to nick the metal, which should then be broken off with the hammer or sledge, as described in cutting iron with the hardy. ”

“ Drawing, the process of spreading or extending metal in a desired direction, is accomplished by hammering or by pressing the metal between such tools as the swages and fullers, or by holding it on the anvil and using either of the set hammers, the flatter, or the fuller. When using any of these pressing tools for drawing, a helper is supposed to use the sledge to deliver the blows upon them.
It is always best to draw round metal with the swages, as it will be smoother when finished than if it were done with the hammer ”

“ In the case of magnetic ores, roasting converts the ferrous oxide into ferric oxide, which lessens the possibility of the iron becoming mixed with the slag, thereby preventing considerable loss of metal.
Ore is frequently calcined in open heaps, but in more modern practice stalls or kilns are employed. Where fuel is cheap and space is abundant, the first process may be used. A layer of coal a few inches thick is laid on the ground, and a layer of ore is spread upon it; then coal and ore are laid in alternate layers until the pile is from 4 to 9 feet high. ”

“ What is a forging? Name the machines used in making forgings. Who invented the steam hammer? How should material be held on the dies? What tool is used in place of a hot cutter at the hammer? How can a convex end be produced? Describe the special form of a trimming chisel. How should metal be broken after it has been nicked with the cold cutter? Describe the correct way of using a hack in cutting square stock. Explain the use of a checking tool. Describe the different fullers used at the hammer. ”

“ They are considered more valuable as a curiosity than as material for manufacturing purposes. The metallurgist, chemist, or geologist can readily distinguish them from other masses, because they invariably contain considerable nickel, which seldom appears in any of the ordinary iron ores. They are usually found in a mass containing crystals and are nearly always covered with a thin coating of oxide, which protects the metal from further oxidation. ”

“ If steel is heated so that the outer parts are hotter than the center, the metal will forge unevenly. The outer portion will be forged by the hammer blows, while the center remains almost in the original form. This will also cause an uneven grain, sure to produce cracks when the tool is hardened. Forging at too low a heat will injure the steel in the same manner as uneven heating. ”

“ Why is steel graded according to its carbon content? Explain the cause of fire cracks. How can they be prevented? Why should steel be thoroughly healed? If steel is overheated or burned, what is the effect? Why should steel never be left in the fire to soak up heat? How does steel forge if it is unevenly heated? How should the blows be delivered in forging steel? What is annealing? Describe three methods of annealing. Is it best to anneal cold chisels and lathe tools? Explain the process of hardening steel. ”

“ Basic iron is that which is generally used in the basic process of steel manufacture. It should contain as little silicon as possible, because the silicon will attack the basic lining of the furnace; therefore the surface of the pig iron used for this purpose should, if possible, be free from sand. By the basic process of making steel, most of the phosphorus in the pig iron is removed, consequently basic iron may contain considerably more phosphorus than if it were to be used in the Bessemer process. ”

“ The hardening or refining heat is always lower than the forging heat, and should be only as high as is necessary to harden the steel to the required density by sudden cooling. Then this first operation of cooling will harden and refine the steel at the same time.
Extreme hardness is always accompanied by extreme brittleness, a quality undesirable in any cutting tool, and especially so in a tool required to withstand sudden shocks. As the hardness is reduced by subsequent heating, the toughness increases. ”

“ The furnace is built mostly of brickwork with the exception of the supporting beams, doors, tie rods, and hearth castings, which are made of cast iron, wrought iron, or steel. All brickwork that comes in contact with the intense heat is made of silica brick, manufactured from rock crystals, flint, or other varieties of quartz rock with about two per cent of quicklime. The roof of the furnace slopes toward the center, so that when the air and gas enter they are directed downward on the charge of metal. ”

“ The noticeable difference between the lower and higher qualities of steel proves that the greater the quantity of carbon, the harder will be the welding, and if the experiments were extended to still higher carbon steels, it would be discovered that they could not be joined except by the use of a specially prepared flux. There are indeed some high carbon steels that cannot be welded. ”

“ Iron Ore.—An ore is a portion of the earth’s substance containing metal for which it is mined and worked; the class to which it belongs depends upon the amount and variety of the metal it contains. Any ore that is to be used for the extraction of a certain metal must contain the metal in sufficient amounts to make the operation profitable. ”

“ Great care should be taken in hardening and tempering each of these cutters to prevent possible injury from small particles of steel that might fly from them if they were tempered too hard. The cold cutter should be hard enough to cut steel or iron without being broken or battered on its cutting edge. The hot cutter should not be quite so hard and should be dipped in water frequently when it is being used to prevent the temper from being drawn. ”

“ As a commercial product, such as is used in the arts and manufactures and by the smith, it is always combined with other substances, such as carbon, silicon, and phosphorus.
Iron is distributed through the earth very widely, but not always in sufficient quantities to make its extraction from the ore profitable; consequently the ores used for the extraction of iron are somewhat limited. There are four general grades of iron ore, which are known by the following names: magnetite, red hematite, limonite, and ferrous carbonate. ”

“ What is steel? Name the different qualities, giving the approximate carbon contents of each. What is the old test for iron and steel? How was “blister” steel produced? By what process is cast or tool steel made? What sort of vessel is used in melting the materials? State the differences between making tool and soft steel. What is an ingot? What is the difference between an ingot of tool steel and an ingot of soft steel? What is meant by the piped end of a tool steel ingot? How are these ingots classified? How is octagon tool steel made? What processes are used in making soft steel? ”

“ By holding the piece of steel against a hardy, swage, or fuller, the scarf can be hammered down tightly over the tool steel, which should hold it securely for heating. Place the pieces in the fire and heat them to a red; remove and thoroughly cover them with borax; replace them and raise the heat to a bright yellow or welding heat.
While the first light blows for the welding are being delivered, the end should be held against something to prevent the steel from being displaced; when positive that welding is proceeding, make the blows heavier and complete the operation. ”

“ Upsetting is not a very difficult operation as long as the metal is kept perfectly straight; otherwise the task42 will prove tedious and the metal may break from the constant bending back and forth. Bending will always take place, but breaking generally can be prevented by having the metal hot when it is straightened. The greatest difficulty in this respect will be experienced when operating on common wrought iron.
Upsetting by hammering is done by holding the metal perpendicularly on the anvil or something solid enough to withstand the blows which will be delivered upon it. ”

“ Holes can be punched with ordinary handle punches, but care should be taken not to have them too long; even then a bolster or something must be used, so that the punch can be driven clear through the metal and not come in contact with the lower hammer die. ”

“ The Drop Hammer.—The drop hammer is provided with a pair of dies made of cast steel, one upper and one lower, having suitably shaped depressions made in them for forming the forgings. The lower die is held stationary on a solid foundation block, and the upper one is secured to a heavy weight or hammer. This is raised perpendicularly and allowed to drop upon the metal, which is held on the fixed die by the smith, thus forming the forging. ”

“ If the work is small and simple, all depressions may be made in a single pair of dies, and the forging can be completed with one hammer and without changing the dies. Work somewhat complicated may require two or more pairs of dies, with various shapes of depressions. The stock is broken down or blocked out by the first pair and then completed by the stamping and finishing dies. Larger pieces may require also a number of pairs of dies, then an equal number of hammers may be used, each fitted with a set of dies. ”

“ The Hammer Blows.—Metal can be forced into desired shapes or forms by delivering the hammer blows in different ways. All hammer blows are not alike; some will have one effect and others will produce an entirely different result.
45. The upright blow is delivered so that the hammer strikes the metal in an upright position and fully on the anvil. Such blows force the metal equally in all directions, providing the surrounding dimensions are equal. ”

“ Fire Tools.—The necessary tools required for maintaining the fire and keeping it in good working condition are shown in Fig. 4. A is the poker with which the coke can be broken loose from the sides. B is the rake with which the coke can be moved over the fire on top of the metal to prevent the air from retarding the heating. The shovel C is used for adding fresh coal, which should always be placed around the fire and not on top. In this way unnecessary smoke will be prevented, and the coal will slowly form into coke. ”

“ The best method of making bends of this kind is to heat the metal only where the bend is to be, and then to bend it by pressure or pulling, while the work is held securely in the vise, hardy hole, or swage block. If the heating cannot be confined to the desired space, all excessively heated parts should be cooled. ”

“ Grading by analysis, although not universally used at present, is no doubt the more perfect method, because the foreign substances contained in the metal can be accurately determined. Grading by fracture is more generally used, although it cannot be considered absolutely perfect, but when done by one who has had years of experience and has trained his eye to discover the different granular constructions and luster of the fractured parts, it is very nearly correct ”

“ The blooms from either the open-hearth or puddling process are treated similarly in what is termed the forge; this includes hammering, rolling, and shingling.
Fig. 151.—Rolling Tool Steel.
Squeezers or hammers are used for forming the bloom and expelling the inclosed slag. The bloom is then put through the largest groove of the roughing rolls and passed back through the next smaller, and so on until it is rolled down to the desired size. Figure 151 shows 14-inch rolls in use which, although somewhat similar to those employed for rolling iron, are larger and generally made with more rolls. ”

“ If the end of a bar is being upset, and the upsetting is supposed to extend up through the bar for some distance, the heated end should be placed on the anvil as shown in the figure, because the anvil will slightly chill the end of the bar, and the upsetting will continue much farther43 than if the blows were delivered on the hot end. Striking the hot end with the hammer increases the diameter of the end excessively, because the contact of the hammer does not have a tendency to cool the metal. ”