Though none but a professional smith could hope to undertake elaborate works in wrought iron and steel, yet many simple jobs can be done with a very moderate amount of practice, such as the bending, drawing down, upsetting, shaping, and welding of the plainer kinds of work.

In a small shop, an ordinary forge would be rather cumbersome. Hence one of the small portable forges would be preferable to a mass of brickwork and iron, if it were not for the difficulty of carrying off the smoke. If the forge is to be in a closed building, there must be a hood and chimney. If, on the other hand, it could be placed without the building, protected by a lean-to roof, a portable rivet or similar forge would be lighter and less expensive. The circular bellows in Fig. 213 are either of the single or the double blast type, the latter giving a continuous current of air, but being also the more expensive of the two. Forges with 16 in. bellows are the smallest made, and either these or 18 in. would be the handiest for a small shop. A light framework of bar iron supports the circular hearth. The circular bellows are carried beneath, and are worked by the handle, levers, and rocking shaft, the blast being conveyed through the bend pipe into the back of the hearth.

The ordinary fixed forge is built of brick or stone. The hearth bricks simply enclose a hollow space which is filled with cinders, and upon which the fire is laid. The hearth back is of brick or stone, faced at its lower portion with a plate of iron, through which the tuyere passes, and pierced at its upper portion with a square hole leading into the chimney. The chimney need not be long, its function not being the production of blast, but only of a sufficiency of draught to lead away the smoke. The face of the hearth for a few inches inward from the edges is usually covered with a sheet of cast or wrought iron, for the sake of protection to the bricks. Two troughs occupy the front of the forge - a coal bunk, and a slake or water trough, the two often being made in one casting.

Smiths Work 500152

About the cheapest forge which can be made is that shown in Fig. 214, and one which any amateur could construct at a low cost, and with very little trouble. It can be employed out of doors, or placed indoors under a hood and against a wall leading into a chimney. Angle irons for the supports, flat bar iron for the horizontal stretchers, and sheets for the hearth and coal bunk are all that are required. The bearing surface of the angle iron will keep the structure from rocking; but if there is any tendency to unsteadiness when working the bellows, a diagonal brace on each framing will prevent it. The blast may be taken from long bellows placed underneath, and worked by means of a lever handle, set conveniently behind the hearth back, but keyed to a rocking shaft which moves in bearings bolted to the under side of the hearth plate. The rocking shaft passing thus underneath to the front of the forge actuates a lever and connecting rod, completing the connection with the bottom board of the bellows. Or the blast can be taken from a blower at the back, either with single or multiplying gear. A small forge of this type may measure out and out 26 in. long, 22 in. wide, and 30 in. high. The angles may measure 1 1/2 in. X l 1/2 in.

X 1/4 in., the bar stretchers l 1/4 in. x 1/4 in., and the sheets about 1/8 in. thick.

The supplying of the blast is effected either by means of bellows of circular or long pear-shaped form or by fans or by blowers, and in these matters the purse and the convenience of the user would be consulted. Bellows are worked by a handle and rocking staff, and attached to the forge, or distinct therefrom, according to convenience. A fan is preferable to bellows, and is worked by hand or foot, or power, but should be driven with multiplying gear to get up the speed. In factories a single fan worked by a belt from the engine supplies blast to a range of forges; a throttle valve under the control of the smith regulating the passage of the blast to each forge. Numbers of small forges are now sold very cheaply fitted with fans, or with Root's blowers, so that the old fashioned leather bellows seem to be doomed to ultimate extinction. A small fan is shown in Fig. 215. The cheeks A are of cast iron grooved to a bare 1/8 in. deep a, to take the strip of sheet iron or brass B, which is cemented in with white lead and clamped together with bolts b passing between the sides. The fan spindle c is carried in bridge-like bearings D, bolted to the sides of the cheeks, and the fan itself is composed of dished sides of sheet iron or tin E, between which the vanes d are soldered.

The dished sides are soldered to brass rings e, which run against the inner faces of the cheeks. The vanes or blades are also soldered to the curved ribs /, on the central boss, made of gun metal. The actual fan requires to be nicely balanced, owing to the high speed at which it rotates. The fan sides are each furnished with a central hole to admit the air. Instead of flat cheeks^ two castings can bo made with curved outlines, and bolted together with a central outside flange, in the manner so familiarly known in foundry and other fans; but this means the making of two rather troublesome half patterns. The form of blade used in the common old fashioned fan is shown in Fig. 216, but it is noisy. It is easy to make, the blades revolving within the outer casing, and as close to the sides without actually touching them as possible.

By multiplying gear, we mean some arrangement by which the proper speed of a fan can be imparted without excessive labour at the hand wheel. A hand wheel driving direct to the fan pulley will do, but with multiplying gear smaller wheels and less work will effect the same results. The perspective view (Fig. -217) illustrates this gear, the relative positions of the wheels varying as best adapted to the forge itself, and, of course, a treadle can be substituted for the handle. As drawn, the wheel A would be to one side of the forge clear of the hearth, its bearing being bolted to the hearth back, the bearings of the other wheels being bolted to the stretchers underneath the hearth. 10 in. would be a good size for the wheels A and B. Bunds are preferable to ropes running round grooved pulleys, since the latter properly require tightening gear for alterations in length due to temperature.