Читать книгу The Young Mechanic - James Lukin - Страница 5

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There never was a time when a taste for practical mechanics was so general among boys as it is now, in this year of grace 1870. There are comparatively few homes in which evidences of this hobby are not apparent in every odd nook and corner, in the shape of carpenter’s tools, not always in first-rate condition, nor by any means generally in their proper places. A saw here, a hammer there, a gimlet, bradawl, or chisel elsewhere.

This probably results from the giant strides which have been made of late years in mechanical enterprise, and the introduction of machinery into every department, as a means of saving labour and facilitating the production of the various necessaries of life.

Man is an imitative animal, and in this as in other things “the child is father to the man;” and hence it comes to pass that the boy whose eyes are continually resting upon machinery of one sort or another (agricultural implements, if a villager; engines for planing, sawing, turning, and so forth, if resident in a town) sooner or later feels an innate desire to construct models of these gigantic mechanical labourers, by whose incessant but unfelt toil our several daily needs are so cheaply and plentifully supplied.

Even if the youthful mind does not always display highly-developed inventive faculties, there is very generally manifested a desire of personally constructing some one or more of those articles which conduce to the gratification of a particular hobby. If the boy has a taste for natural history, cases and cabinets will be made, for the reception of eggs, butterflies, and insects, or to contain stuffed specimens of animals and birds. If he has within him the elements of a sailor, his ingenuity will be exercised upon model boats and ships. If fond of dumb pets, rabbit hutches, dove-cots, or cages will afford him opportunities for the exercise of his constructive powers, and thus the young mechanic frequently lays the foundation of future eminence in that particular line of life to which his tastes naturally lead him.

There are few boyish hobbies in which assistance has not of late years been given by instruction books and guides of a high degree of excellence—natural history, botany, gardening, rearing and breeding all manner of pets—to each of these, well-written volumes have been devoted by able and experienced writers, but mechanical and constructive art has been somewhat neglected. Here and there, in periodical magazines, a few pages are dedicated to the subject, but no book about practical mechanics, written expressly for boys, has yet appeared.

The author of the present volume, himself father of four lads, all of whom in turn occasionally try their hands at this kind of work, and who has himself for many years practised the mechanical arts of carpentry, turning, and model-making, hopes that the hints contained herein may prove valuable to those young friends whom he now addresses. Some of the following chapters will be arranged for very little boys, some for those who are older, while it is believed that other parts of the work may not prove altogether useless to those who have dropped jacket and knickerbockers and rejoice in the vigour of manhood. Thus the little boy, who receives the book as a present, will find it a fast and faithful friend as his years, and, we trust, knowledge and bodily powers increase.

“Small boys need few tools, but much perseverance.” Let this be their motto, as it will stand them in good stead. A pocket-knife, gimlet, hammer, and a few nails will generally serve their purpose; but there is one other tool, namely, a square, which is of great importance, and of which it is well to learn the use as early as possible. A small saw and a bradawl may also be added to the list, and likewise a chisel half an inch wide. Thus equipped, a very youthful carpenter can do a good deal, and, let me tell him, a good deal has been often done without even this moderate supply of tools. It must be taken for granted that the knife and chisel are sharp, because blunt tools make bad work, and by far the best plan for small boys is to get some friend to sharpen them when blunt, as the operation is not easy and requires practice. It is a very foolish plan to try and work with a blunt knife, for the fingers are just as much in danger; and a boy who intends to learn how to use tools must learn at the commencement to use them with due care, so as not to damage himself.

There are small boxes of tools sold, containing generally a wooden mallet, saw, plane, chisel, and gimlet, at about 3s. 6d. or even 5s. Such a box is simply useless. The tools are of iron—will not take a good edge, and are generally disposed to bend and twist. Avoid these, and buy, or get a friend to buy, those I have named, of good quality, and be sure to take care of them, for which purpose you may try your hand at making a box. For this purpose, you will require some thin board (half-inch thick) planed on both sides. (The carpenter will prepare this for you.) Let us see how much you will need. Measure your longest tool, the chisel or saw, if the latter is quite a small one fit to go into a little box; if not, it can be hung on a nail, and you can make your box to contain your knife and chisel and gimlets. I daresay if the box is 9 inches long, 4 inches wide, and 3 inches deep, it will be large enough to take these few tools, for I have just now measured such a hammer and chisel as I have recommended, and find them each about 9 inches in length. The top and bottom of a box should project a little all round, so that you will want them about an inch and a half wider and longer, which will also allow for the thickness of the wood; for you must remember we have given the size of the box inside. To make this clear, I shall here give a plan of the bottom of the box (Fig. 1).

Fig. 1.

Fig. 2.

Fig. 3.

It is 10½ inches long, and 5½ inches wide. The broad black line shows where the edges of the sides and ends will come, these being half an inch thick, so that there is a quarter of an inch all round the outside as a border. Reckon across and you will understand this better. A quarter of an inch outside, half an inch for the black line (equals three-quarters of an inch), 4 inches for the inside width, half an inch again for the black line, and a quarter of an inch outside as before,—altogether making 5½ inches. Now reckon the length. A quarter-inch border, half an inch for the black line, 9 inches inside, half inch for the second black line, and another quarter outside—making 10½ inches. You require, therefore, two boards 10½ inches long and 4½ wide for the top and bottom. Now the two long sides and the ends are to be 3 inches wide to form the depth of the box, and here you want no extra width, but as the inside of your box is to be 9 inches long, and the sides are usually nailed over the ends, like Fig. 2, where I have shown them put together, you see that you must have the sides as much longer than 9 inches as will allow them to lap over the ends; that is, half an inch at each end where I have made them black, or altogether, one inch; so that you will want two pieces 10 inches long and 3 wide. The ends will be also 3 inches wide and 4 inches the other way, and here no additional size is needed. Now, the usual way to cut the sides is to get a narrow strip of board of the required width and thickness, and long enough to make both the sides and ends, just such a piece as Fig. 3, on which are marked the lines where it will have to be cut across, and you will easily perceive that you require 28 inches in length and 3 in width.

But you must understand that when you cut with a saw you waste a little of the wood, which falls in the shape of sawdust, and so if you did not allow for this, your box would be too small. The waste depends on the thickness of the edge of the saw, where you will, if you examine it, see that the teeth spread out right and left to prevent it from sticking fast as it is used. Probably, you would waste three-eighths of an inch, which is nearly half an inch in cutting off the pieces, so that instead of a piece exactly 28 inches long, you must have it 28½ inches, or even a little more.

I want you to understand all this before you set to work, even though at first you may get a carpenter to measure and cut it for you; because most small boys take no trouble of this kind, and consequently they are sure to make their boxes too large or too small, and they look very bad when done. However, as I said before, I expect my young readers to understand what they are about, and they must set out their work carefully, or they will never get on so as to be able to make good use of the later chapters of this book. A carpenter’s rule is made like this (Fig. 4).

Fig. 4.

Sometimes there is a brass slide, to add to its length when necessary, and sometimes it is hinged so as to fold up again. If you want one for your box, you can get it so made, when it will go in nicely. It is 2 feet long—1 foot on each side of the central joint. A foot is 12 inches; the whole rule, therefore, is 24 inches. Now, you will see that each of these inches is divided by short lines into eight equal parts, called eighths; at the second, the line is rather longer, this being a quarter of an inch; at the fourth, there is a still longer line, this being the half-inch; then comes another eighth, then the three-quarters, another eighth, and the inch is made up,—eight-eighths being equal to one whole inch. Very likely you will find one edge of the rule, or sometimes only one inch, divided into smaller parts, which are sixteenths, or half-eighths; and sometimes, but not very often, divisions still smaller are used, which are half-sixteenths, or thirty-seconds, because thirty-two such divisions make the complete inch. Three feet make one yard, but carpenters always reckon by the foot and inch, and by eighths and sixteenths of an inch. In some trades the inch is divided into a hundred parts, and work is measured up and fitted so carefully, that it would be considered faulty if a mistake of less than a thousandth of an inch were made; but you will not yet understand how it is possible even to measure so very small a quantity. You should certainly learn and understand how to measure with a common two-foot rule, and when you can add one to your box of tools, do so.

Now, let us examine the tool called a square, without which the marks could not readily be drawn as a guide for the saw, where the strip of board is to be cut to make the sides and ends of the proposed box. Here is a drawing of one (Fig. 5).

Fig. 5.

Fig. 6.

It is a handle and a blade, like a knife half opened, the one being fixed exactly square, or at right angles with the other. The blade is thinner than the handle, and when the latter is placed as in Fig. 6, a line marked across the board against the edge of the blade will be, of course, square to the side, so that when cut off, the piece will be like the end of Fig. 6. This is not the shape which the sides of boxes generally have when made by small boys, because they have not a square, and do not know how to work properly. Nevertheless, if one end of a board is cut square, you might get the piece right by measuring the same distance on each side (say 10½ inches), and drawing a line across from point to point, as a guide for the course of the saw. But, then, as it is absolutely necessary that the end of the board should be square to the side, to do this you had better get a proper square at once, and learn how to use it. You will, indeed, find this tool most necessary for all kinds of work, and you will be quite unable to do without it, even though you only have, besides, a knife and gimlet.

Now, if you want to cut off a piece of board with the saw, you must never cut out the line you have marked as a guide by the help of your square, because if you do, you will get the piece too short, owing to the width of the saw-cut which I explained before. Cut, therefore, just beyond it, leaving it upon the piece you are going to use for the side of your box, or other article. At first, you will find it difficult to saw neatly and close to the line, but you will get used to it very soon; and if the saw does not go quite straight, you can trim the piece with a sharp knife neatly up to the line, which you see you could not do if you cut out that line by sawing exactly upon it. All these directions in little matters are very important, because you will find that, by attending to them, you will work well, and the various things you make will look neat and trim, and be fit to show to your friends.

Now, let us go on with the box, which was laid down just to allow a little explanation about the carpenter’s rule and square. I shall suppose you to have cut off all the pieces quite squarely and neat, and that the edges are also square to the sides, which you must take care to insure by keeping the blade of the saw upright when you use it. It is a good plan to measure and mark both sides of your board for this purpose, and to mark the edges from one of these lines to the other. You will then have guide-marks all round, and, by keeping close to these, you will be sure to cut your work truly. It would not so much signify if the long sides were cut a trifle too long, as I shall explain presently; but the ends must be square and true to measure, 4 inches by 3 inches. You must now proceed to nail them together. This must be done with small brads, which are fine nails, and which for the present purpose may be one inch long. If your pieces are all exact to measure, draw a pencil line across the two side pieces, a quarter of an inch from the ends, by the help of the square, as if you wanted to cut off a quarter of an inch at each of those parts, and with your bradawl make two or three holes (three will be best) along those lines. Do not make the first and last too near the edges, or you will split the wood, and spoil the box. Now set up one of the short pieces, and place upon it the piece which you have bored holes in. If you have a bench with a vice, you can screw up the short piece into it; but it will stand up very well upon the bench if you have no vice. It is now in the position of Fig. 7, C.

Fig. 7.

Hold it thus, and run the bradawl a little way into the lower piece, through the holes already made in the upper. Drive a brad through the middle hole first, which will hold it together, and then through the other two holes. If you have been careful, you will find this corner square and neat, and the wood not split in the least. Do the same with the other short piece, and then nail on the long side that is left. The frame of the box will now be complete.

I told you a short time ago, that it would not much signify if the sides were cut too long. The reason is this: Suppose B to be the side half an inch too long. You would mark off 9 inches of the middle by two lines drawn with the square as before, which would be the length of the inside of the box; you would then place the inner edges of the end pieces against these lines, and nail them on like A, and afterwards neatly saw off the two pieces which lap over these at each end. If the wood is likely to split when the holes are made for the nails, or if the workman is pressed for time, he very frequently does his work in this way, and then cuts it off and planes it neatly. It is, however, better to work as directed, only be sure to bore holes carefully for the nails, so as never to split the wood.

No very special directions are needed about putting on the bottom. Leave all round an exactly even border of a quarter of an inch, and after it is nailed, you may neatly round off all its edges, to give it a finished appearance.

The cover is, of course, to be attached by a pair of small hinges. Brass hinges are the neatest, and when you buy them, ask for screws to match. The hinges may be three-quarters of an inch long, and they will be, when shut, about half an inch wide, which is the size you need. Lay them (shut up) upon the edge of the back, about two inches from the ends, and with a hard pencil cut to a fine point, or with the point of your bradawl, make a mark at each end, as if you were measuring the length of the hinges on the edge of the box. Between these marks you have to cut out pieces like Fig. 8, which will be just the length of the hinges, and deep enough to allow them, when shut up, to fit and lie even with the top edge of the box. Open them, make holes with the bradawl, and put in the screws. If you have not a screwdriver, you can turn them with the end of an old knife; but you may as well get a small screwdriver, for if you intend to do good work, you will often use screws instead of nails. Hinges are always screwed on. Now lay the cover in place carefully, mark its position, so that you have some sort of guide-line to direct you, and then by laying the cover flat on the bench, and standing the (open) box on its side, you can screw on the hinges upon the cover. Round all the edges of the cover as you did the bottom, but keep the edges of the box square and sharp; and so you have now a really well-made little tool-chest. A little brass hook and eye will do to fasten it, for a lock is rather difficult for a small boy to put on.

Fig. 8.