The Atlantic Monthly, Volume 12, No. 72, October, 1863 / A Magazine of Literature, Art, and Politics

by Various

These buildings were all constructed in the most substantial manner, of stone and brick, and yet remain in an excellent state of preservation. The trouble and expense attending the transportation of the various parts of the musket from one series of shops to another, however, rendered it desirable to assemble them all in one place, and the location of the upper shops was decided upon as the most advantageous. About eight years ago the work of constructing the new shops was begun. Extensive excavations were made for a new dam, the bed of the stream was changed, the sides being laid for a distance of half a mile with freestone, and the basin raised five feet above its former level. Some idea of the magnitude of these works may be formed from the fact that over one million dollars was expended upon the foundations alone, before a brick was laid in the superstructure.

A beautiful and extensive series of buildings has since been erected upon these foundations, covering an area of about two acres, in which the forging, boring, welding, rolling, grinding, swaging, and polishing are done for the entire establishment. The buildings are, for the most part, two stories high, and yet so immense are the operations carried on here that numerous temporary sheds have been erected about the grounds, in which machinery is placed in order to increase the facilities, which, when the works were constructed, were supposed to be sufficient for all time to come.

Since the construction of the new dam, the water has a fall of thirty-four feet. Three immense turbine water-wheels, having a united power equal to three hundred horse, were put in when the consolidated works were first constructed here, which it was supposed would prove amply sufficient for all emergencies; but, since the breaking out of the Rebellion, and the marvellous enlargement of these works, it has been found necessary to put in a steam-engine of two hundred horse-power, to act in conjunction with the water-wheels.

Having thus given a general description of the exterior of the establishment, let us now enter the works and witness the entire operations of manufacturing the musket, seriatim.

The first operation is the formation of the barrel. Formerly these were made from plates of iron called scalps, about two feet long and three inches wide, which were heated to a white-heat and then rolled up over an iron rod, and the edges being lapped were welded together, so as to form a tube of the requisite dimensions,—the solid rod serving to preserve the cavity within of the proper form. This welding was performed by tilt-hammers, which were carried by the water-wheels. Underneath the hammer was an anvil containing a die, the upper surface of which, as well as the under surface of a similar die inserted in the hammer, formed a semicylindrical groove, producing, when the two surfaces came together, a complete cylindrical cavity of the proper size to receive the barrel to be forged. The workman, after heating a small portion of the barrel in his forge, placed it in its bed upon the anvil, and set his hammer in motion, turning the barrel round and round continually under the blows. Only a small portion of the seam is closed by this process at one heat, eleven being required to complete the work. To effect by this operation a perfect junction of the iron, so that it should be continuous and homogeneous throughout, without the least flaw, seam, or crevice, required unremitting attention, as well as great experience and skill. The welders formerly received twelve cents for each barrel welded by them, but if, in proving the barrels, any of them burst, through the fault of the welders, they were charged one dollar for each barrel which failed to stand the test. This method has now, however, been abandoned, and a much more economical and rapid process adopted in its place. Instead of plates of two feet in length, those of one foot are now used. These are bent around an iron rod as before; but in place of the anvil and tilt-hammer, they are run through rolling-machines, analogous in some respects to those by which railway-iron is made. The scalps are first heated, in the blaze of a bituminous coal furnace, to a white-heat,—to a point just as near the melting as can be attained without actually dropping apart,—and then passed between three sets of rollers, each of which elongates the barrel, reduces its diameter, and assists in forcing it to assume the proper size and taper. The metal by this process is firmly compacted, becoming wholly homogeneous through its entire length.

This operation of rolling the barrel is not only a very important and valuable one, but very difficult of acquisition, the knowledge appertaining to its practical working having been wholly confined to one person in this country previously to the breaking out of the Rebellion. The invention is English, and has been used in this country but a few years. Only one set of rollers was used at this armory until the present emergency demanded more. About half a dozen years ago the superintendent of the works here sent to England and obtained a set of rollers, and a workman to operate it, bargaining with him to remain one year at a stipulated salary. At the expiration of the time engaged for, the workman demanded, instead of a salary, to be paid eleven cents for each barrel rolled by him. As he had allowed no one to learn the art of rolling the barrel in the mean time, his demand was acceded to; but after the breaking out of the Rebellion four additional rolling-mills were imported, and of course new men had to be taught, or imported, to work them. The art is now no longer a secret. There are forty men employed, day and night, running the rolling-mills, but, instead of twelve cents, which was paid for welding, they now receive but four cents for rolling a barrel, with the same contingency of a dollar forfeiture for each one that bursts. Four persons are employed at each mill, namely: the foreman, who sees to the heating of the scalps and barrels; the straightener, who straightens the barrel after it passes through the roller; the catcher, who stands behind the roller to catch the barrel when it has passed through; and the fireman. The rollers weigh two tons apiece, and the five sets turn out one thousand barrels per day, one per cent. of which burst in the proving-house.

The barrel when rolled is left much larger in the circumference, and smaller in the bore, than it is intended to be when finished, in order to allow for the loss of metal in the various finishing-operations. When it passes into the roller, the scalp weighs ten pounds; when it comes from the roller, the barrel weighs a little over seven; when completed, it weighs but four and a half: so that more than one half of the metal originally used is lost in the forging, or cut away by the subsequent processes.

The first of these latter is the boring-out of the interior by machines called boring-banks, of which the water-shops contain a large number, in constant operation day and night. These machines consist of square, solid frames of iron, in which the barrel is fixed, and bored out by a succession of operations performed by augers. These augers are square bars of steel, highly polished, and ground very sharp at the edges, and terminating in long, stout rods to enable them to pass through the barrel. The barrels are fixed very firmly in the boring-banks, the shank of the auger inserted into the centre of a wheel placed at one end of the bank, and a slow rotary motion given to the auger, together with a still slower progressive motion at the same time. By this means the auger gradually enters the hollow of the barrel, and enlarges the cavity as it advances. After it has passed through, another auger, a trifle larger, is substituted in its place, and thus the calibre of the barrel is gradually enlarged to nearly the required size. Formerly, six borings were given to each barrel, but at the present time only four are permitted, aside from the rifling, which is a distinct operation, performed at the works on the till, and will be described hereafter.

After the boring of the barrel, it is placed in a lathe, and the outside turned down to the proper size. The piece is supported in the lathe by means of mandrels inserted into the two ends, and there it slowly revolves, bringing all parts of its surface successively under the action of a tool fixed firmly in the right position for cutting the work to its proper form. The barrel has a slow progressive as well as rotary motion during this process, and the tool advances or recedes very regularly and gradually, forming the proper taper from the breech to the muzzle, but the main work is performed by the rotation of the barrel. In the boring, it is the tool which revolves, the piece remaining at rest; but in the turning, the barrel must take its part in action, being required to revolve against the tool, while the tool itself remains fixed in its position in the rest.