Alexander Lyman Holley
Blades Described and Classified. Forger's Implements and Apparatus. Coke, its Nature and Manufacture. Marking, Hardening and Tempering — Different Methods. Tables of Colors, Baths, Temperatures, etc. Improvements. Fuel. Bituminous Coal. Charcoal.
Published Saturday, June 8th, 1850 in the American Railroad Journal
Note: I've hand-typed the below words from the original publication as the text, at times, is difficult to decipher and has proven impossible to perform OCR on.
The different parts of a knife blade are called the faces, back, edge, point, neck, swages, tang and nailmark. The swages form a blunt edge, upon the blade's back, the corners having been removed. — They are of two kinds, the "common swage" commencing at or near the neck, increasing in width toward the centre, and ending at the point of the blade. They are comparatively easily formed, therefore confined wholly to the coarser varieties of knives. The “knicked" or “cut-in" swage commences with a shoulder, usually near the point, and tapering, ends at the point. This is usually considered more neat and handsome than the other, and the forger receives a greater price for making it. The tang is the part of the blade which reaches from the cutting part to the end opposite the point, on which is the manufactoreal stamp, and the joint. The "shoulder" of the tang on its back, by striking the spring end, keeps the blade open, and at any desired angle with the handle. The “kick" is the part of the tang on which the blade rests when shut, thus keeping it from striking the edge on the back of the knife.
Blades are divided into three great classes, viz: job, pen, and pocket blades. The first class is indescribable, comprising all odd and uncommon blades, each of which is adapted to some particular work. The next class is subdivided into spear, square, forward and blunder joints, and nail blades. On spears the joint is in the centre of the face, the edge and back terminating there convexly. The edge of square points should never be convex, and the point is the diagonal of a parallelogram. The edge of forward points is either hooking, straight or regularly concave, the back being convex near the point. Blunder points are always concave on the edge, till within one-eighth or one-half an inch of the point, (which is like the spear) and there very convex. These blades are usually considered “homely,” except by cutters, but are fashionable, and well adapted to cutting. Nail blades usually terminate with a blunder point, the face being files. These are especially adapted to cutting and trimming the nails, though convenient for other purposes.
Pocket blades are divided into six classes, viz: forward and spear points, corboe, cemetery, razor and dirk blades. The two first are like the same varieties of pen blades, only shorter in proportion to their width. Corboe blades are similar to forward points, except shorter in proportion to their thickness and length, and the convexity of the back commences nearer the tang. The name implies the shape of the razor, dirk and cemetery blades.
The nailmark is of two kinds, the “common,” or crescent shaped, and the “French,” which is a long straight impression very near the back, commencing at the nicked swage, (for they usually go together) and extending to the tang and over from one-half to three-fourths of the face of the blade. This is considered more neat and handsome than the common mark. The nailmark is always on the “mark side” of the blade, though the mark side, as it is termed, of the knife, is the one on which is the nail nick of largest pocket blade.
We will first describe the old English manner and means of forging blades, though at present those of making all pen and most pocket blades. The forgers occupy a room by themselves, furnished individually with a forge somewhat smaller than a blacksmith’s, and a trough and bellows in proportion. The chimney is very large, in order to give free passage to the gas and smoke in coking. The anvil, which runs at right angles with the outside of the forge that the operator may turn but one-quarter round to strike, is about 15 inches in length 5 ½ wide and 12 deep, sunk about six inches, and wedged into a large post, which is set firmly into the earth. In front of this is a stationary table, called the bench, from three to four feet long, and from 12 to 18 inches wide, with sides two inches high, and al covered with sheet iron, and a little lower than the top of the anvil, extending to the forge on the left, (for the operator always turns to the right from the fire to the anvil,) and some 12 inches on the right. Before this table is the wall, and a window. The surface of the anvil is smooth for some three inches on the right, with a shoulder in front, and convex toward the table, then filled with mortices, into which the bosses, chisels and gauges are wedged. The bosses for forging are blocks of steel, from one-half to two inches broad, and from three-fourths to two inches long, with square shoulders in front, convex outer edges, and surfaces level lengthwise, and convex the other way. The “bits” of the tongs, which are of different sizes, are on one side of the “shanks,” the the bar of steel may project beyond the rivet. The hammers are iron, faced with steel, weighing from 2 ½ to 5 ½ pounds, into which the handles are fastened near the top. A small but hot fire is made of Liverpool coke, which is bituminous coal freed from all hydrogen gas, water and tar, and a large portion of its sulphur, by fire. It is either of a dull jet black appearance, or when made in a blade forger’s fire, it exhibits a vitreous or metallic lustre, with a porous texture, and is not as heavy as raw coal - for 20 pounds of the latter will produce but from 14 to 16 pounds of coke. It is valuable in proportion to the amount of carbonaceous substance it contains, and that coal is preferable which exhibits a soft, dull appearance of carbonized vegetable matter. Small pieces of coke may be occasionally selected from large quantities, that can hardly be distinguished from charcoal. For blast furnaces it is but a substitute for charcoal, and is manufactured in hearths in great quantities. In a dark night, the appearance of these long hearths is exceedingly grand and beautiful. In front the dark figures of the operatives, and the lurid fires blazing like a burning crater, and emitting dense columns of black smoke which rise to the clouds in the rear, may well remind one of Vulcan’s Etnean forges, and the fires of the Cyclops and the Broutes.
For some purposes, coke is made in ovens from six to eight feet broad, eight feet high, and eighteen inches diameter at the top. In this country, blade forgers make coke daily, and enough at once for a day, by placing on the fire about three shovels full of coal, which is no sooner subjected to a blast front the twyeres, than it begins to emit a very light brown thick smoke, which in the evening, as it slowly and heavily curls up, is very beautiful and well worth seeing. This smoke, which is exceedingly dense, is hydrogen gas and tar, with some sulphur, which is highly inflammable, and as soon as the least blaze front he fire below comes in contact with it, it instantly vanishes and leaves the dark mass of coal sending forth streams of fire from every point. As the heat increases, by constant stirring and a strong blast of wind the coal gradually expands, and becomes coke as above described, when it is sprinkled with water to quench the fire, and is then ready for use. The bars of steel, which usually measure from ⅜ x 3/32 to 1 x ¼ inches, are cut into convenient lengths, and two at once placed in the fire. The first process is called “mooding,” and consists of partially shaping the blade and cutting it from the bar. In this operation only one side of the blade is made, and the other left level with the bar. The next process termed “tanging,” is forging the tang with a second heat, which in pen blades requires from 20 to 24 light blows from a good workman’s hammer. At the next heat the blade is “smithed.” By this operation, the other face and shoulder of the blade are forged, the nail mark cut on a curved stationary chisel, and the swages struck. The blade is also trimmed, straightened, and brought to an edge and its shape and proportions perfected, which require but a few strokes of the hammer. The steel must not be heated to too high a temperature, as before mentioned, and the tang in particular should not be hammered when cool, for in that case it is liable to draw forth sundry unpleasant screams, etc., from the drill which bores it, and sarcastic observations from the cutler who files it.
The blade is then “choiled” by another hand; which consists of simply running a three square file once or twice through the neck or that which joins the cutting part to the tang, to give shape to the blade, and to remove the “Flash” or superfluous particles which the forger leaves, and which cannot be removed by the grinder. They are then passed through a process termed “laying on,” which is leveling the mark side of the tang and other parts which are to receive the manufactorial stamp, on grindstones, in order that the latter may not be erased when again ground and polished. The forger then receives the blades again, and places them in a long row on a steel plate over a slow fire, and as fast as they turn blue at the temperature of about 590 degrees F. the words and characters are impressed with a stamp of steel types. The best of these stamps or marks are made in Sheffield, England probably with very small chisels, though there the art of cutting them is a secret. The object of blueing the blades is to slightly soften them, and particularly to color the letters which are sunk below the level of the tang, and if bright might be illegible.
Hardening is the next operation, which shows one of the remarkable and invaluable qualities which steel alone is known to possess, though from recent experiments on swords and coins by Drs. Pearson and Dize, it is supposed that the ancient Greeks and Romans were unacquainted with a method of hardening either copper or an alloy of some eight or nine parts copper and one of tin If steel at a great heat is suddenly plunged into cold water, it becomes extremely hard and brittle, though the lower the heat sufficient to produce this effect the better the quality of the metal, and the greater its compactness the less the heat required. It is necessary also, in order to ensure an equal degree of hardness in all parts of the instrument, to thoroughly cleanse the surface previous to heating, as any oxide of iron will produce a contrary effect. Saline solutions have been tried for hardening, also a current of cold air and mercury, but nothing has proved so effectual as water, provided the steel is heated to a low temperature. Oil is often tried particularly for large blades, being less liable to crack them than water.
To be continued…