Supplement to the Fourth, Fifth, and Sixth Editions of the Encyclopædia Britannica/Anvil
ANVIL, in Smithery, and other manufactures of the malleable metals, is an instrument on which substances are laid for the purpose of being hammered.
For some purposes, anvils ace made of cast-iron; but, when the face of the anvil is required to possess great hardness, or a bright surface, it is made of wrought-iron, and faced with steel. The core or body of wrought-iron anvils is prepared at the forge, where malleable iron is first formed into bars, or into masses for any particular purpose. The body of the anvil is formed by welding a number of smaller masses together under the forge-hammer. These are rude blocks of different sizes, according to the size of the anvil. Smaller masses are also furnished in this way, which the anvil-maker occasionally welds to the large blocks, for giving to the anvil any particular form.
The fire-place or hearth of the anvil-maker’s forge is similar to the common smith’s forge. His bellows are not double, like the latter. His fuel is cork, which produces a great heat, without much flame. Adjacent to the hearth is a crane, which, turning upon a pivot, brings the heated masses of iron from the fire to the anvil. The latter is a large mass of cast metal, about eighteen inches square on the face, and about a foot from the ground. When the core of the anvil to be formed is heated, the first thing is to make three square holes, one in the bottom, and one at each end of the anvil. These holes are about 1¼ inch long, 1 inch broad, and about 2 inches deep. They are for the purpose of receiving a bar of iron, which is connected with the crane by which the anvil is held in the fire, and by which it is turned and guided while forming with the hammers.
The common smith’s anvil is generally made of seven pieces, namely, the core or body; the four corners, for the purpose of enlarging its base; the projecting end, which contains a square hole, for the reception of a set, or chisel, to cut off pieces of iron; and the seventh piece is the beak, or conical end, used for turning pieces of iron into a circular form, welding hoops, &c. These pieces are each separately welded to the core, and hammered so as to form a regular surface with the whole. When large pieces are required to be welded to the core, one fire is not sufficient to heat both at the same time. In this case two hearths are employed. The core and the piece are both raised to a welding heat. The piece being put into its place, is hammered by a quick succession of blows, till it adheres. The whole is again heated and hammered till the due form is obtained. The hammering is performed by a number of men at the same time, each using a large swing-hammer. The blows follow each other in regular succession; great experience and care being required to prevent the hammers from coming in contact with each other.
When the anvil has received its due form, it now requires to be faced with steel. This is performed by first preparing the steel face to the size of the anvil. The anvil is then heated to a strong welding heat in one fire, while the steel facing is heated in another, but not so hot as the iron. The anvil is now brought out, and placed in a proper position, and the facing is brought to it. The surfaces, which are to be brought together, are brushed, and the facing is then laid on, and hammered as rapidly as possible, till it is closely united. The whole is finished by repeated heating and hammering.
The next process is that of hardening the anvil. This consists in heating the face, in particular, to a full red heat, and quenching it in cold water. When a stream of water can be employed it is better. Where this cannot be had, the mass of water should be great, and the anvil moved about as quick as possible. The facing should be laid on as thin as it can be firmly welded. When it is too thick it is apt to crack in the hardening.
After hardening, the face is ground till it is perfectly even, and the edges made sharp, or round, as may be required. When the anvil is required for planishing metals, it is polished with emery, and afterwards with crocus.
The smith’s anvil is generally placed loose upon a wooden block, the root-end of an oak tree being preferred. The anvils used in cutlery, and for files, are fastened into a large block of stone, which is doubtless better than having the anvil loose upon a small block. The more firmly the anvil is connected with the earth, and the substance it stands upon, the greater will be the effect of the blow of the hammer. (T.)