The art of forging is one of the oldest in the history of man. As already noted in "Foundry Work," while the art of smelting must have preceded that of forging, the latter antedated by many centuries that of making castings of iron. It is probable that in the early years the metal was rare and costly. Its being used for personal adornment seems to prove this. Such examples are the iron finger rings found in the tombs of the ancient Egyptians. Comparatively few specimens of ancient wrought iron work have been discovered however. This is due to the fact that it rusts so readily. Gold, silver and bronze, on the other hand, do not corrode rapidly. According to Pliny the best steel used by the Romans was imported from China, where iron is said to have been worked as early as 2000 B. C. During the Middle Ages iron working reached a high state of development in Europe. This is shown in the beautiful designs of wrought iron found in the churches and palaces of the time. Hinges, brackets, balconies, knockers, grills, armor and weapons were executed of the most intricate and artistic designs. The entrance door of the Hall of Merton College, Oxford (shown in Fig. 1), is an example of this work.
Although this work was beautiful and delicate, it was all light and could be made by hand. The forging of the heavy frames and shafts that we have to-day would have been impossible with the appliances then available. The steam engine makes present forgings possible.
The work of the smith became changed somewhat when the arl of making castings was discovered. From this time on, the delicate, intricate designs were made by casting and the smith devoted himself to making forgings of strength rather than beauty. As the demand for artistic forgings decreased, that for mechanisms increased until to-day artistically hammered work is counted among *the Luxuries of the Few. The products of the forge find appliea-tion in all grades of modern mechanisms, from a lady's watch fa armor of a modern battleship.
STEEL PRESSURE BLOWER. Amerknj) Blower Company.
The Materials upon which the work of foging or blacksmithing is done, are wrought iron and steel. As explained in " Metal-hirgy,"' wrought iron is an iron from which "the silicon, phosphorus and must of the carbon has been removed." Steel usually oon-taias some of the impurities that are characteristic of cast iron with the marked peculiarity of holding a varying percentage of Carbon. Mild .steels are so-called on account of the small amount of carl on which they contain. As the percentage of carbon increases, it becomes more difficult to weld the metal. Greater care must also be used in heating lest the metal be burned and its strength destroyed. Until recently all heavy forgings involving welding, were made of wrought iron, but new processes have made it possible to weld steel. It is now possible to procure heavy steel castings that may be bent, twisted and when broken, can be welded.
The properties which it is necessary for a metal to possess for forging are ductility and malleability. Many of the steels are not welded but are hammered into shape from a single original piece. The various kinds of steel are described in "Metallurgy".
The Shop may vary in size from the small blacksmith shop with a single forge to the great establishment fitted with ponderous steam and power hammers and innumerable fires and furnaces. There are, however, a few common characteristics of all such shops. The floor should be of earth or cinders. The ground beneath should be well drained. A good method of laying a floor is to excavate to the depth of about 18 inches and fill in 12 inches of this with broken stone. Cover with a layer of finer stone and use earth for the top. This makes a macadamized floor. If the shop is connected with a machine shop, the floor can be still further improved by covering to a depth of ½ inch or so with cast iron chips. When these have been wet a number of times they rust together and form a hard even surface. .
The walls of the building are preferably of brick. The roof may be of wood or iron, with a slate covering. It should also contain a monitor ventilator along the ridge pole through which smoke and gases may escape. IE iron work is used in the con struction of the roof, it, should he thoroughly protected from corrosion by an asphalt or graphite paint. The side walls should be .imply supplied with windows, and the ventilation should be as complete as possible.
A distinction is usually made between a blacksmith shop and a forge shop. The difference lies in the weight of the work and the method of doing it. In the blacksmith shop, the work is usually done by hand and is heated in open fires. In the forge shop machinery is employed to do the work, which is heavier, and the heating is done in a closed furnace. The difference is, therefore, one of degree and not of kind. The two classes of shops will be treated separately.