The next articles required are a setting-down piece, fig. 17; three hollow rammers, or drifts, figs. 18, 19, and 20; and one solid rammer, fig. 21. They are simply cylindrical pieces of wood, turned with a head, to bear the blows of the mallet. Beech, or box free from knots, will answer. The lengths of figs. 18, 19, 20, and 21, are to be 8, 6, 4, and 2 diameters, respectively, exclusive of the head; that is, 6, 41⁄2, 3, and 11⁄2 inches. The hollow drifts are to have a cylindrical, not conical, hole, bored up them, with a nosebit, or twist drill, to within one inch of the handle, so as to clear the spindle by 1⁄2 an inch, to allow of any dust being driven up it. The hollow in figs. 17 and 18 must be large enough to fit the spindle loosely at a; in fig. 19, a trifle smaller, to fit loosely at b; and in fig. 20, a trifle smaller still, to fit loosely at c.
The next requisite is a mallet, fig. 25, which may be of ash, or beech. It may be a cylinder, 5 inches long, and 3 inches diameter, with a handle about 5 inches long, and 1 inch diameter. Let it be turned at the end slightly concave, like the bottom of fig. 16, that it may be set to stand upright, like a wine bottle. Or the head may be made 3 inches square, like fig. 26; or, a small carpenter's mallet, about a pound and a quarter weight, will answer.
To Charge Rocket Cases.
The first requisite is a solid block of wood, 6 or 8 inches square, and 18 or 20 high. This is indispensable. A piece of an old oak gate post, answers well. It must be set upon the ground, or on a flag stone, not on a floor. It is impossible to ram a rocket properly on the floor, because of the vibration. It is, also, necessary to sit, not stand, at the work.
Put the setting down piece, fig. 17, into the case; press the case over the spindle, and give the head a few blows with the mallet; this will smooth out the wrinkles of the choke, which is all that fig. 17 is used for. Now put in a very little powdered clay, and mallet it with fig. 18; as much clay as will reach up 1⁄12 of an inch will be sufficient; its object is to preserve the choke from burning, and getting enlarged. One cannot be too precautious with rockets. Now put in a scoop of rocket fuse, insert drift, fig. 18, and mallet the fuse in firm, with about a dozen and a half blows, or till it offers a resistance to the hand. The blows must be light and numerous, not slow and heavy, like driving a post into the ground. 18 blows with a momentum of 3, will consolidate the fuse: 3 violent blows, with a momentum of 18, would perhaps bend the case, or drive the dust up into your eyes. The mallet need not be lifted above 4 or 5 inches at a time. If the rocket is not rammed firm throughout, it will, upon lighting, explode.
As soon as the case is charged about 11⁄2 inch, make a pencil or ink mark, round the drift, where it stands level with the top of the case, for future guidance; then charge another 11⁄2 inch with the second rammer, fig. 19, and mark it in like manner; proceed in the same way with fig. 20. It is obvious that if fig. 19 were used too soon it would get split by the spindle being driven up it, and the spindle would be bent or broken, hence the advisability of marking the drifts to know when to lay aside one, and take the other. Just before you get to the top of the spindle, put in the solid rammer to feel how high the spindle reaches near the top of the case; hold it by the thumb and finger to keep the distance, and mark it down the outside of the case, by indenting the case with the edge of the drift. Exactly 11⁄3 diameter, that is, in this case, exactly 1 inch, above this indentation make another mark: then as soon as you have covered the spindle, till you can no longer see it, with the use of fig. 20, begin charging with the solid drift, fig. 21, till the composition inside is level with the top mark. This being done drive in a little dry clay, till the case is full. Remove the rocket from the spindle, by giving it a turn or two round to the right, not backwards; then bore a hole through the clay, till you can see the composition, with a 3⁄16 inch shell-bit. The shell-bit should be fixed in a handle, and kept for the purpose. It is not advisable to use a stock and bit, unless the bit is shielded, as it is apt to bore too deeply. The bit may be fixed in a handle, by boring a large hole in the handle, and pouring in melted lead, or pressing in plaster of paris.
Instead of driving in dry clay on the top of the composition, a little plaster of paris may be pressed in; this, when dry, will allow of a perfectly clean hole being bored through it; whereas the clay is apt to crumble, and chip out. The object of the clay, or plaster, is to prevent the composition, which, containing much charcoal, does not bind well, from getting disturbed, and the solid part diminished, which would cause the stars to be ignited while the rocket was ascending, or the fuse, perhaps, to blow through at the beginning. A piece or two of naked quickmatch is to be inserted in the hole through the clay or plaster, and a long piece is to be pushed up the core, or hollow, of the rocket, as far as it will go; it is, then, to be cut off flush with the mouth, and fastened to the side with a little dab of wetted meal powder, pressed on it with the blade of a knife. If the rocket is intended to be lit with a port-fire, take a circular piece of touch-paper, about 2 inches diameter, slightly paste it all over, lay it in the left hand, press the mouth of the rocket down upon it, and smooth the edges of the touch-paper up round the case. Otherwise, smear the end of the case with the sash-tool dipped into meal paste, and when dry, paste a bit of touch-paper round it, and twist to a point, like a squib. The appearance of the rocket is shown at fig. 36; the dotted line round the mouth shows the touch-paper.
In driving with the hollow rammers, it generally happens that a little of the fuse gets driven up the hole; this, if allowed to accumulate, is very troublesome to remove; it should, therefore, be knocked out every time, by holding the drift in the left hand, and giving the head a rap or two with the mallet.
The whole of the composition ought to be put in in about 12 scoops: try 2 or 3 scoops till you get one of the right size, then write upon the handle what-sized rocket it belongs to. These directions may appear minute, but they will save much trouble if attended to.
As it is convenient to know, beforehand, about what quantity of composition will be required for any particular rocket, the following formula will be useful:—