Fig. 71, A, is a tube of sheet-iron, which forms the body of the little stove. Four light iron rods stand out from it, which form handles, but these are forked at the ends, and thus become rests for the handles of soldering-irons, or any light bars that are to be heated at the ends. Below is a tray, also of sheet-iron, upon short legs to keep it off the table—for this is a little table-stove. C is the cast-iron grate. You can buy this for a few pence first of all, and then you fit your sheet-metal to it. It will rest on three or four little studs or projections riveted to the stove inside; or you can cut three or four little places like D, not cutting them at the bottom line, a b, but only on three sides, and then bend in the little piece so as to make a shelf. If the stove is about 4 inches high above the grate, and 2 or 3 inches below it, and 6 inches diameter, it will be sufficiently large for many small operations; but that the fuel may keep falling downwards as it burns, the lower part should be larger than the upper, and, to admit plenty of air, should be cut into legs as shown. Round the top are cut semicircular hollows, in which the irons rest. To increase the heat, a chimney or blower, B, is fitted, which has also openings cut out to match those of the lower part, so that the soldering-irons can be inserted when this chimney is put on. If, however, this is not required, but only a strong draught, by turning the chimney a little, all the openings will be closed. A still longer chimney can be added at pleasure. A hole should be made at the level of the grate to admit the nozzle of an ordinary pair of bellows. This stove you would find of great service, and it may be fed with coke and charcoal in small lumps. Now you may make the above far more useful. It will make a regular little furnace, and not burn through, if you can line it with fireclay. In London and large towns you can obtain this; and it only needs to be mixed up with water, like mortar, when you can plaster your stove inside an inch thick or more, making it so much larger on purpose. There is no need to do this below the level of the grate; but if you cannot get fireclay, you may do almost as well by getting a blacklead-meltingpot from any ironfoundry, and boring a few holes round the bottom for air, and fitting it inside your little iron stove. In this you can obtain heat enough to melt brass, and it will last a great deal longer than the iron alone, which will burn through if you blow the fire much; but for general soldering, tempering small tools, and so forth, you need not blow the fire, as the hood and chimney will sufficiently increase the heat. There is no danger in the use of this little fireplace, but of course you would not stand it near a heap of shavings, unless you are yourself a very careless young “shaver.”
Fig. 71.
HOW TO TEMPER TOOLS.
There is no reason why the young mechanic should not be told how to make his own tools, and how to harden and temper them, because he ought to be a sort of jack-of-all-trades; and perhaps he may break a drill or other small tool just in the middle of some special bit of work, or his drill may be just a little too small or too large, and there he will be stuck fast as a pig in a gate, and unable to set himself right again any more than the noisy squeaker aforesaid. But to a workman a broken drill means just five minutes’ delay, and all goes on again as merrily as before; and as we wish to make our young readers workmen and not bunglers, we will teach them this useful art at once.
Drills are made of steel wire or rods of various sizes. In old times they were made square at one end, to fit lathe-chucks or braces, but now, for lathe-work, they are generally made of round steel, and fastened into the chuck with a set screw on one side. In this way they can be more easily made to run true. But there are so many kinds of drills that I suppose I had better go into the matter a little—only I have not room to say much more.
Fig. 72.
Look at Fig. 72, and you will see some of the more usual forms of drills used, but these are by no means all. You will not indeed require such a collection; and yet, if you should grow from a young mechanic into an old one, I daresay you will find yourself in possession of several of them. The first, labelled 1, is the little watchmaker’s drill, of which, nevertheless, this would be considered a very large size. It is merely a bit of steel wire, with a brass pulley upon it, formed into a point at the largest end, and into a drill at the other. The way it is worked is this: At the side of the table-vice—that is, at the end of its jaws or chops or chaps—are drilled a few little shallow holes, in which the watchmaker places the point at the thickest end; the drill-point rests against the work, which he holds in his left hand. A bow of whalebone, a, has a string of fine gut such as is used for fishing, or, if the drill is very small, a horse-hair; and this is given one turn round the brass pulley before the drill is placed in position. The bow is then moved to and fro, causing the drill to revolve first in one direction and then in the other. The general work is in thin brass, and therefore these little tools are sufficiently strong for the purpose. Some of the drills and broaches (four or five, or even six sided wires of steel) are so fine that they will bend about like a hair, and yet are so beautifully made and tempered as to cut steel.
No. 2 is a larger drill, even now much used. In principle it is exactly similar to the last, but the pulley is replaced by a bobbin or reel of wood, made to revolve by a steel bow with a gut string, or a strong wooden bow. The drills, too, are separate, and fit into a socket at the bottom of the drill-stock. The large end is pointed, as in the last, and is made to rest in one of the holes in a steel breast-plate, b, which is tied to the chest of the operator, who, by leaning against it, keeps the drill to its work, while both hands are free to hold the latter steady. There is a modification of this tool, invented by a Mr Freeman, intended to do away with the bow. The bobbin or reel is turned without raised ends, and is worked by a flat strip of wood covered with india-rubber, and turned at one end to form a convenient handle. The having to twist the bow-string round the drill, which is always a bother, is thus done away with.