This section is from the "Modern Machine Shop Construction, Equipment, And Management" book, by Oscar E. Perrigo. Also see Amazon: Modern Machine Shop Construction, Equipment, And Management.
For convenience in bringing in stock and taking out finished work the tram car tracks run nearly midway through the forge shop, as shown, and are connected by their branches with the foundry, the machine shop, storage sheds, and practically all departments of the plant, as well as at three points with the railroad track, two of these being shown on the plan.
The foreman's office is located in the front corner of the shop, and has connected with it the usual foreman's store closet for such minor supplies as are more conveniently kept there than in the general storeroom near the offices. A fixed desk furnishes a convenient place for spreading out drawings, and a private desk is provided for the foreman's personal use. Outside of the office is a forge shop scale for weighing stock and forgings. This scale should be mounted on wheels so that it can be readily moved to any part of the shop where it may be needed.
Along the outer wall of the shop are located five regular forge fires having chimney flues built into the wall for their accommodation. These latter will not be necessary if the system of down-draft forges is used. This form of forge has several good qualities, not the least of which is that it offers less obstruction in handling large pieces of work, as it may be conveniently placed at a distance from the wall if desired, and will furnish quite as good ventilating facilities in clearing the shop of coal gas as those connected with separate chimneys. The draft may be increased or decreased at the will of the operator, particularly in the case of forges manufactured by the Buffalo Forge Company, in which a hinged and adjustable hood may be closed down over a fresh fire and raised for the handling of the work to be heated, as may be desired. If these down-draft forges are used it will be necessary to provide an exhaust fan with the proper connecting pipes for carrying off the smoke and gases, which may be delivered to one chimney, thus avoiding the expense of building the other four. Such an arrangement is very clean and wholesome for the workmen, when compared with the method shown, but considerably more expensive in its first cost, as well as requiring extra power to operate it.
The forges shown on the plan should be of such construction that the tuyeres may be readily attached and detached when necessary, for cleaning or for repairs. They should have such a form of bottom valve or gate as to readily discharge the clinkers or slag that may find its way down to it. These forges are usually constructed of cast iron and supported upon four legs, so as to give convenient access beneath them for cleaning, attaching the blast pipe, repairing, etc. Each should have, cast with it, or attached to it, two narrow troughs, running the length of its front, or shortest side, for holding coal and water. Many excellent ones are in the market and can be purchased more economically than they can be built on the premises. The blast pipe should be arranged to slide on and off easily, in case it is necessary to disconnect it for cleaning or repairs, and it should be provided with a regulating valve or gate, fitting as nearly air-tight as may be, and operated by a lever conveniently located within the reach of the operator. These forges are usually made of rectangular form, but large fires are often made upon a circular forge, whose sides extend to the floor. They need not necessarily be provided with the water and coal troughs as mentioned above, as they are usually used for heating work for the steam hammers, drop presses, and similar large work, rather than for tempering, tool forging, or small work of this class.
The blast for these forges, for the heating furnace, for the drop presses, and for the case-hardening and annealing furnace, is furnished by a fan blower designed for a pressure necessary for forge work, and having an outlet of six inches in diameter, equivalent to a No. 3 Sturtevant steel pressure blower, which is admirably adapted for this purpose. It should be located over the bench near the forges, at the front end of the shop, so that there may be no unnecessary turns or bends in the pipe leading to the forges. These pipes should be placed along the walls near the floor, but never beneath it. In one shop the author saw blast pipes, composed of vitrified drain tiles, the joints made with Portland cement, and laid less than a foot beneath the surface of a dirt floor of the forge shop, and at one point passing directly under a bolt heading machine.
As might have been expected, the jar of the shop floor broke up the pipes and destroyed their usefulness. The blast pipes should be constructed of heavy galvanized iron, well fitted and fastened, and as nearly air-tight as may be. They should be easy of access, for the possible connection of additional pipes and for convenience of making repairs, which will have to be made sooner or later. They might be placed six or seven feet high, and along the walls, but this position will necessitate about thirty feet of additional pipe, increasing the friction of the air and consequently the power required, with no especially compensating gains other than getting the pipes up out of the way somewhat.
Some of the more important rules for setting up and connecting forge blowers may be here given. Place the blower as near as possible to the forges. Make the pipe connections as direct as possible. If bends or elbows are absolutely necessary, make the curves of large radius, and with no abrupt angles; the inside radius of an elbow should not be less than twice the diameter of the pipe. Have the aggregate areas of all the outlet pipes at least equal to the delivery pipe at the blower. If the pipes must carry the air over one hundred feet, speed up the blower proportionately above the figures given in the manufacturers' catalogue. In any event, the blower should be run at such a speed as will give four to five ounces pressure at the tuyeres, not less than four ounces at the forge farthest from the blower.