By perusing the foregoing definitions, the learner will be enabled to understand the details given concerning individual forgings.

Round Keys Without Heads

Fig. 1, Plate 1, represents a simple kind of round key ; and this, with other keys shown in a line with it, are proper objects for learners to attempt during their first essays at forging.

A round key is so simple that no forging is necessary to make it, unless the key is required to be about half or three-quarters of an inch in diameter. Small round keys are made immediately from the wire, which can be bought of iron or steel, of a suitable diameter, to avoid unnecessary labour. All small keys should be made of steel, whether they be round or square. If the steel is obtained small enough to obviate the necessity of forging, it should be cut to a convenient length for holding while being filed to fit its place, which is named the key-bed or key-way. Steel wire is easily divided by an edge of a file. After being cut to convenient lengths, the pieces should be made not more than red-hot, and allowed to cool gradually to soften them, remembering that such keys as we are considering should not be hardened. The advantage in making them of steel consists in two principal good qualities - their closeness of texture and their durability. A small pin or key of steel will sustain much more hammering in and out of the key-bed than an iron key of the same diameter and length. Small iron keys are liable to split while in use, through the number and shape of the fissures that steel does not possess.

But if the steel requires forging, it must be considered whether the pin or key is to be filed to fit the key-bed, or whether it is to be turned. A round key to be turned should be forged with a small portion drawn down from the largest end (Fig. 58), for the convenience of holding it while being turned in the lathe. Round keys are sometimes an inch and a half in diameter, and considerably taper; hence the convenience of the smaller portion at the larger end, allowing the key to be turned throughout its whole length without interruption.

If the key is to be filed to fit, instead of being turned, the smith must be careful to ascertain the proper angle or amount of taper required in the key, and also the finished dimensions. Attention to these particulars avoids unnecessary waste of time while fitting the key. Taper keys should be tried into their key-beds, before the forging of the key is finished. But when a great number of large ones are to be forged, a double-gap gauge (Fig. 57) should be made, one gap being for measuring the large end of the pin, and the other gap for measuring the small end, and both openings of the proper width to allow only a small amount of tiling to the pins while being fitted.

The proportionate lengths and diameters of round keys depend upon whether they are intended for wheels, for levers and weigh-shafts, or for cranks. Fig. 1 shows the proportion suitable for the middle of a wheel, which is named the wheel-boss. Fig. 3 indicates a round key, of proportions suitable for a weigh-shaft or crank-lever, when the pin or key is inserted through the middle of the lever and spindle by means of a hole bored through the two (Fig. 59), instead of merely cutting a key-bed into the shaft, parallel to its length (Fig. 60). Fig. 3, being comparatively small in diameter, admits of a small hole in the shaft or spindle, instead of a large hole, which would needlessly weaken both lever and spindle.

The round pin or key is superior to the angular key for many kinds of work, such as wheels and crank-levers. This circular pin might be used oftener than it now is, because it can be quickly fitted by turning, and also because the curved key-bed is not so liable to break the wheel.

The manipulation of a round key upon the anvil consists in drawing down the end of a long rod, care being taken that the steel is never hammered too near the small end of the key. It is proper to commence the drawing or reducing at the large part of the key nearest the hand, and deliver each successive blow more and more towards the further end, and never contrariwise. For forging a small round key, no tools are required except the ordinary fire-irons and the handhammer, tongs, and anvil-chisel, in the anvil; shown by Figs. 61, 62, and 63. The forging a round pin is good and instructive practice for a beginner, to enable him to see the effect of his blows upon the piece of work. Sometimes he will strike the anvil instead of the key, and there is then a probability of the hammer bouncing up into his face. This will teach him to strike the key gently until he has acquired the method of holding his work upon the anvil, and also of striking upon the top of the key, instead of the side, which puts an ugly dent into the key that he intended to be round, and drives it sideways along the top of the anvil and down to the ground in a very unworkmanlike manner. But all such small difficulties are soon overcome by patient practice. He will soon discover that, if he holds his left hand too high, he will experience an indescribable tingling and jarring in the hand; and if he holds his left hand too low, he will feel a curious jerking of the left arm all the way to his shoulder. One remark concerning holding his work may be useful, and is, that if he is careful to keep two points of the key bearing upon the anvil at one time, and is careful to strike always between these two points, he will not undergo the tingling and jerking just referred to.

The pin should be forged to the proper diameter, and also the ragged piece cut off the small end, by means of the anvil-chisel, shown by Fig. 63, while the work is still attached to the rod of steel from which it is made. After having cut and rounded the small end, it is proper to cut the key from the rod of steel, allowing a short piece to be drawn down to make the holder, by which to hold it in the lathe. This holder is drawn down by the fuller, and afterwards by the hammer. The fuller is first applied to the spot that marks the required length of key ; the fuller is then driven in by the hammerman to the required diameter of the holder, the bottom fuller being in the square hole of the anvil during the hammering process, and the work between the top and bottom fullers. During the hammering, the forger rotates the key, in order to make the gap of equal or uniform depth ; the lump which remains is then drawn down by the hammers, or by the hand-hammer only, if a small pin is being made. If the pin is very small, it is more convenient to draw down the small lump by means of the set-hammer and the hammerman. The set-hammer is shown in Fig. 66 ; and the top and bottom fullers by Fig. 67.

The double or alternate hammering by forger and hammerman should at first be gently done, to avoid danger to the arm through not holding the work level on the anvil. The hammerman should first begin, and strike at the rate of one blow per second; after a few blows the smith, or intended smith, begins, and both hammer the work at times, and other times the anvil. The first attempt continues about a minute, after which the work receives a severe dent on one side, and is knocked off the anvil, and sometimes out of the tongs. After a short time occupied in collecting the various instruments, the operators begin again with renewed vigour.

Fig. 64 shows the top and bottom rounding-tools, for rounding large keys. These tools are necessary for large keys, but it is proper for the learner to make a small key without them. This he can do by rounding the work with his hand-hammer, and cutting off the pin by the anvil-chisel instead of the rod-chisel (Fig. 65). The rod-chisel is so named because the handle by which the chisel is held, is an ash-rod or stick (see Fig. 64). A rod-chisel is thin for cutting hot iron, and thick for cutting cold iron. Fig. 63 represents the anvil-chisel in the square hole of the anvil. By placing the steel while at a yellow heat upon the edge of the chisel, he can easily cut off a small key by a few blows of his hammer upon the top of the work.