The most important manufacture in the Toledo Works, however, is assuredly rifles, and, with the intention of following it through its principal processes, we return to the vicinity of the still inveterate hammer, where we are shown a rudimentary barrel in the shape of a slab of best wrought iron, twelve inches long, and weighing nine pounds and a quarter. This uninviting slab is heated in a furnace, and roughly bent into the tubular shape by means of our enemy the tilt-hammer, after which it is once more placed in a furnace of an enormously high temperature, with a small trap-opening. When sufficiently heated, the short rudimentary tube is taken out on a long round iron rod, fitted with a hand-guard, and looking like a huge burlesque rapier. This rod approximates to the size of the intended bore of the barrel, and is inserted, with the rough tube upon it, between two steam rollers, each of which is furnished with a series of corresponding grooves or cuts. The barrel, which is taken up at one end by a rod, is placed between the first pair of grooves, and, as the rollers revolve, is drawn out at the other side, a long, hollow, welded tube. This much more graceful and better formed tube is then consigned to another rod of smaller diameter, and to a corresponding pair of grooves; until, after the eighth repetition of the same process, the barrel has attained its proper dimensions. The next operation, which is called “lumping,” consists of welding a piece of wrought iron on to the breech end of the barrel, for the purpose of forming the percussion-lump, and is succeeded by “rough-boring.” This is accomplished by a long, sharp-ended bit, which, being placed in the end of the barrel, revolves at the rate of, perhaps, a thousand turns a minute by means of a pulley and fly-wheel, while the barrel is pushed on by a lever, and kept cool by means of water thrown upon its surface.
The “setting” of the barrel is next effected by means of hammer and anvil, the setting meaning simply rectifying any bend which it may have received during the previous operation. We are not a little interested in the setting, since the first intimation of it on entering the shop is the sudden discovery of a number of workmen gazing resolutely at an opposite window, through what look like attenuated telescopes. They are engaged, however, in one of the processes which require the greatest experience, as each of them is expected to detect the most trifling bias in the barrel. The “spilling-up,” or cutting the inside of the barrel to the proper bore, is similar to the rough-boring, except that only one edge of the bit is allowed to operate, the others being sheathed by a half cylinder of wood, called a spill; this ensures a smooth surface, and prepares for the “fine-boring,” which is six times repeated, the final surface being insured by keeping one edge of the bit perfectly smooth, by which means the particles of steel drop in a fine and almost soft powder.
The outside of the barrel is next turned in a long lathe, which not only reduces the roughness, but, by a beautiful arrangement of cutting tools, gives it the required substance or “pattern,” for a light or heavy rifle.
The grinding of the barrels is effected by means of stones, larger than those used for the sword blades, but in a similar manner, and is preliminary to “filing,” which carries the barrel to the shop, where it is prepared for the lock.
Grinding Gun Barrels.
These preparations consist of “chambering,” or making the chamber which holds the pin; “breeching,” or cutting the worm intended for the breech-pin, that helps to hold the barrel to the stock by means of a breech-nail; cutting out the little slice into which the “sight” is to be dovetailed; machining the lump; filing the tail-pin, and making the square lump the proper shape for receiving the lock and stock.
We are not a little surprised to learn that every part of the lock is finished by hand, the cock being cut with a die worked by a heavy weight, and the smaller pieces being wrought with forge, hammer, and file.
Section of Breech. Section of Lock, &c. Bullet Mould. Nipple Key.