In the last chapter we entered a little upon the matter of dovetails, but as the mode of uniting the angles of boxes, drawers, and such like, is of almost universal application, it will be as well to devote a separate short chapter to the subject.

There are several different kinds of dovetails used, according as it may be desired to let them appear upon the finished work, or wholly or in part to conceal them. Carpenters generally use the kind which is visible on both sides, cabinetmakers, as a rule, take special pains to conceal it, only using the other form upon work that is to be afterwards covered with veneer (a thin covering of some ornamental and more expensive wood glued upon the surface of that which is of less value, and of which the article is made).

The dovetail described in the last chapter, as proper for the attachment of the sides to the front of a drawer, is not that which is ordinarily used by the carpenters, but the following, which is somewhat more easy to make, and is the same as would be used for the other corners of such a common drawer as that described.

I must at the outset remind my young readers once again of the standard rule, without due attention to which they have no hope of success in this neat and delicate operation of carpentry. Never cut out your guide lines, but leave them upon your work, and use your square diligently upon the edges of your work, the bottom of the dovetails, sides of the same, and upon the sides of the pins. Never mind the time necessary for this. You are doing work, remember, that is to bear inspection,—work that will stand wear, and be really useful in the household to which you have the honour to belong. You would not therefore like to see open spaces here and there, requiring to be filled up with putty, or the side of the box not truly square to the back and front. And it may be noted here, that if dovetails are properly fitted together, the box or other article will stand firm, even before the glue is added; but if the same are badly cut, and put together carelessly, no amount of glue will avail to hold the work securely; and it would have been as well or better never to have attempted dovetailing, as such bad work would be stronger united by nails, and in any case is but a disgrace to the young amateur mechanic, whose motto should always be, “Whatever is worth doing at all is worth doing well.”

You will remember how you were taught to wedge up mortice and tenon joints with glued wedges, which, becoming part of the tenon, and rendering it larger below than above, prevents it from being withdrawn from the mortice. Now, a single dovetail has the same effect, and is in point of fact of the same shape and size as the tenon with its wedges attached. See Fig. 29, A and B, the first being a wedged tenon, the second a dovetail.

We shall begin with a single dovetail, which is applied to the construction of presses used by bookbinders and others, and also domestically for house-linen. In these there is a strong tendency to draw the sides upwards, and to tear them from the bottom—a strain which this form of joint is exactly calculated to withstand. The same is also used in making many kinds of frames, where similar strength in one direction is necessary. If you have no special need of such at present, you should nevertheless make one or two for practice, and to give you a better insight into their construction. Indeed, if you cannot make single dovetails well, you will hardly succeed in making a whole row of them exactly alike, for joining together other articles, as drawers, boxes, and cabinets. C of this fig. represents a bar of wood truly squared up, and ready for being marked out. The square is laid across it as seen, and a line drawn on each side by its assistance, as far from one end as is the thickness of the other piece to which it is to be attached, and a little over (say one-eighth of an inch) which will afterwards be neatly planed off. This is allowed merely because the extreme angles at e e sometimes get damaged in cutting out the dovetail, and if they are, they will have to be removed. Having drawn the above line all round the piece, divide it into three by the aid of your compasses, as shown, on what we may call the front and back, and then on both these sides draw lines, e e, to the angle. You now have the dovetail, or rather the pin of the dovetail, marked, and with a fine saw you have only to cut out this piece as you see at D, taking great care to cut accurately close to the lines, but to leave them, nevertheless, on the edge of the piece you are about to use.

If you can saw truly, you should not have to touch these pieces with a chisel, but if not, you must take a very sharp one, and pare the wood exactly true to the lines which you have marked. Now the dovetail made by dividing the width of the stuff into three, as given here, will not answer so well for pine, which is liable to split off in the line H H of the fig. D; but for ash, beech, elm, and such like, it is a good proportion. If the material, therefore, is pine, divide it into four instead of three, as seen at E, and draw lines to the angles from the two outer marks; or, without any such division, set out equal distances from each side, so as to give about this proportion to the pieces which are to be cut out.

Where there are a row of dovetails to be made (as in cabinet work), even this latter measurement into four would make them too angular, as you will learn presently. You must now fix upright in your vice the piece in which is to be cut the dovetail to receive this pin; and laying the latter in place as it will be when the frame or other work is put together, draw round it with a sharp pencil or scriber, as seen on the end of K (the lines c d, at such distance from the end of the piece as is the thickness of the pin, and the perpendiculars, a b, are to be drawn with the square); and if the angles of such pin do not reach the angles of that in which the dovetail is to be cut, as will often be the case, the lines on the opposite side similar to a b must be also drawn with the square. So you see that I was quite right in directing you to add a square to your box of tools, even before many other requisites of carpentry.

If it is not considered desirable that the dovetail should reach the extreme angles of the pieces, as a b, fig. K, the pin piece is first marked as if for an ordinary tenon, and the dovetailed pin marked on this, as M. When the fellow-piece is cut out, it will then appear as N. The effect will be the same as the last, except that the end of the pin will be more conspicuous. A great deal depends upon the material, and on the intended use of the finished article, therefore you must use your own judgment, or consult that of others better acquainted with the art than yourself. L shows the dovetailed joint complete as last described.

We now recur to the row of dovetails and pins—or dovetails and sockets, as the part is often called which is to receive the pins. The most common kind is that represented by A B, Fig. 30; and as you ought now to be thinking of a larger tool-box, and would not like it roughly nailed together like the first, you might try your skill by constructing one more worthy of the name, and with a drawer or two in it. You must begin, as before, by marking the two lines across your work by the edge of the square, or, if you prefer it, by your gauge, which, when set to the thickness of one piece, will mark the others correctly; and remember to mark both sides. Then set out your dovetails, but do not make them so angular as you did the single one; for remember you have a whole row of them to assist in holding the work together, and when glued, this will be of necessity a very strong and reliable joint, if well made.

Always make the pins before the sockets, and mark round them as closely as possible, and take great care when sawing not to break them, and if possible keep their angles also very sharp and clean. It is solely care in these particulars, and accurate cutting just to the gauge lines and no further, that makes carpenters’ work generally so superior to that of amateurs, and boys especially are generally careless, and in too great a hurry to get the work done, that they may go to something else. Remember, therefore, that when you begin to hurry your work, you begin to spoil it.

I have made the drawings of the three principal dovetailed joints so plain as to render special description almost unnecessary after the remarks already made. The second and third, however, may need a few words, as they differ slightly from that used in the drawer, of which a description has been given, chiefly because the piece in which the dovetails are, is, in this case, as thick as that used for the sockets.

Suppose the dovetails and pins marked out ready to be cut. Take your marking-gauge and set the slide about a quarter of an inch from the point, and run a line across the ends of the two pieces at A B, and at C D, and also at E F. Stop at A B when you cut the sockets, and take care to get the bottoms of these quite square and even. Cut the dovetails or pins as directed in making the drawer, but stop on the lines e f and g h (the latter also to be made with the gauge on both edges of the work), thus the two pieces will, of necessity, fit nicely together, and only a single line will appear a little way from one corner. If all lines are made with gauge and square, this form of dovetail may require neatness and care, but will not be beyond the skill even of a young mechanic. I should indeed advise that every opportunity be taken of joining pieces of wood with tenon or with dovetail, because, after all, these are the chief difficulties to be encountered. If you can square up your work, and make true-fitting joints, there is little in carpentry and joinery that you cannot accomplish.

The third example is worked exactly like the second, but instead of leaving square the pieces projecting beyond the dovetails and pins, these are sloped off or bevelled carefully from the extreme corners down to the pins and sockets. The result is, that when put together, no joint appears, as it is exactly upon the angle. There is no neater or stronger method than this of joining the sides of drawers, boxes, trays, and such like articles. The cabinetmaker employs no other for heavy work; only when it is very light does he make use of a plan, the appearance of which is (when finished) like the last-described, but it is less trouble to make, and less strong, yet sufficiently so for many purposes. This method is called mitring, and is accomplished in the following way.

The wood (let it be for a small tray) is prepared as usual, truly and evenly, and the ends exactly square to the sides. If you use stuff about a quarter or half an inch thick, or even an eighth (the first or last being suitable for such light work), you can make a mitred joint with the help of the gauge alone, but frequently a mitre-board or mitre-box is used, which saves some trouble in measuring and marking. It is well, however, that you should begin with this trouble, and take up the easier method afterwards; especially as it will in this case give you a simple lesson in mathematics, and teach you some of the properties of the figure called a square. Let us commence with this lesson.

A, B, C, D, Fig. 31, is a square; the lines at the opposite sides are parallel,—that is, they are exactly the same distance apart from one end to the other. To make this clear, E and F are given, which are not parallel, for they are further apart at one end than they are at the other. And as A B is parallel to C D, and A C parallel to B D, so A B is perpendicular to B D and to A C, or what we have called square to it, as you would find with your square, which is made, as you know, to prove your work in this respect. The consequence is, that the angles (or corners) are all alike, and are called right angles. Understand what is meant by angles being the same size or alike. M and H are alike, though the lines of one are a great deal longer than those of the other; but though the lines of K and H are the same length, the angle K is much smaller than that at H.

As I have gone a little into this subject, I will go a little further, for it is as well that you should learn all about the sizes of angles, and I only know of one way in which to make the matter clear.

Every circle, no matter how small or large, is supposed to be divided into 360 equal parts, called degrees. That large circle which forms the circumference of the earth is considered to be so divided. Now, if we draw lines from all these divisions to the centre, they will meet there, and form a number of equal angles. I have not divided the circle P all round, because it would make so many angles that you could not see them clearly; but I have put 360 at the top, and then 45, which means, that if I had marked all the divisions, there would be 45 up to that point. Then at 45 more I have marked 90, and so on, marking each 45th division, and from these I have drawn lines to the centre of the circle. Now, if you understand me so far, we shall get on famously. Look at the line from 360 to the centre, and that from 90°, and see where they join. This is a right angle, and this is the angle at each corner of a square. At N, I have drawn this separately to make it clear, and you see I have taken a quarter of the circle, or the quadrant, as it is called, of 90°. And you now see that I might extend the lines beyond the circle to any extent, but it would make no difference,—we should still have 90° of a circle, only the circle would be larger, as those which are partly drawn with the dotted lines.

Now, all angles are thus measured by the divisions of a circle; the line at 45, which meets the line from 360 at the centre, makes with it an angle of 45°, which is half a right angle. A line drawn at 30° would make an angle of 30 with the same line from 360, and so on right round; only when two lines come exactly opposite one another, as 360 and 180, or 270 and 90, these make no angles—they are but one straight line passing through the centre, and are called diameters of the circle, a word which means measure through, or across the circle. Now, the corners of a square frame, or of a drawer or box, are right angles of 90°. At R, I have drawn such a corner of a frame, and if I place one point of a pair of compasses at e, and draw a circle cutting through the lines of the sides of the frame, you see I should make it 90°, or a quadrant, like N. Moreover, if I draw the sides of the frame as if they crossed as at e R, I draw a small square, and the line e R is the diagonal of such square: e R is the mitred joint I have to cut. Look at T S and you will see this, as here the two sides of the frame are represented as cut ready to be joined together.

A square has another quality: all its sides are equal, and this is very important, and will help us in cutting out the work. x Y represents the strip of wood to be properly sloped off for a mitred joint. With a gauge such as that just above x, or your regular marking gauge, set off on the side Y a distance equal to x x (the width of the pieces); join x b by a line, and you will have the right slope. Why? Because when you measured with the gauge you marked the two equal sides of a square, and x b is the diagonal of it, which is exactly the same as you had at e R. By measuring in this way, therefore, you can, if your strips are already truly squared up, always mark out a mitred joint correctly. The two little angles at x and b are also, I should point out, equal—each half of a right angle or 45°, and the other strip or side of the frame will make up the other half right angle, or complete the exact square of 90°.

In all this I have clearly laid down the principles of mitred joints, and given you a lesson in mathematics. I shall now, therefore, go on to the work of practical construction (Fig. 32). You must be very careful to make the edge B square to the side A, as in all other work which I have explained to you; or, if this side is moulded like the front of a picture-frame, you must square the edge with the back. After having cut all the pieces, you have to glue them and fasten them together. Warm them, and use the glue boiling, as directed before, and quickly lay the pieces together. To do so effectually, you must place them flat on a board or on your bench, and having adjusted them, you can tie a strong cord round the whole, putting little bits of wood close to the corners, so that the string shall not mark your work, if such marks would be of consequence. Or you can wedge up strongly in another way. If you look at C you will see a square representing a frame with eight spots round it. These are nail heads, and mark the position of eight nails driven round but not touching the frame into the bench. Then, having prepared eight small wedges, drive them in between the frame and the nails.

You will find this as simple and easy a way of keeping the frame together as any, and all must remain till the glue is dry and hard—probably till the same hour on the following day? Then remove the wedges and take up your frame, which should be trim and strong. Nevertheless, you are now to add considerably to the strength of it in one or both of the following ways.

With a mitre-saw or tenon-saw cut one or two slits at each angle, as seen at D, Fig. 32, e and f. Cut little pieces of thin wood, and having glued them, drive them into these slits. If you saw them slanting, some tending upwards and some downwards, it will be better than cutting straight into the frame. Then, when all is dry, neatly trim off these pieces even with the frame. You may also, if the work is of a more heavy kind, as a large picture-frame, finish with keyed mitres, g. Cut a place with a chisel of the shape here shown, about one-eighth of an inch deep, half into one piece and half into the other. Then cut out a key of the same form of thin hard wood, to fit exactly, and glue it in. The shape of the key prevents the joint from coming apart, and makes it very strong and durable. A very large number of light boxes are made with mitred joints, as workboxes, water-colour boxes, compass-boxes, and such like; and you can examine these for yourself; but you will not often see the keys at the angles, because most of such boxes are veneered, or covered when finished with a thin layer of some ornamental wood.

I shall now proceed to show you how these joints can be cut at once without the trouble of gauging and measuring to find the proper angle. Therefore I shall let you into the secret of mitring boxes and mitring boards, which, if you had much to do of this kind, would shorten your work considerably.

Fig. 33, A, represents a mitring-board, B a mitring-box. We must go into a little mathematics again, and try to understand these, because, if you do so, you may devise others, occasionally more suitable for any special work you have in hand.

First, look at D of this figure. You have a line, a b, standing upon another C D, and perpendicular to it—that is, it leans neither to the right nor to the left. It makes two angles at b, one on each side of a b, and these are angles of 90°, or right angles, as I explained. Now, if one line like a b stands on another, these two angles are together equal to 180°, or twice 90°, whether this line is or is not upright or perpendicular to the other. Look at fig. C. Here you have the line x x, and standing on it several others; one, a b, is upright or perpendicular, making with it two angles of 90° each, or 180° together. Now, take f b, and suppose this to make 45° on the right-hand side, you see it makes therefore a proportionately larger angle on the other. It makes, in fact, an angle of 135°. But 135° added to 45° equals 180°, which is the same as before, and whichever line you take, the angles together made by it at b will equal 180° of the circle—that is, they will equal two right-angles.

Now, if I take the fig. D again, and carry on the line a b right through c d, where it is dotted, two angles will be made on the other side of c d, which will each be right angles of 90° as before, so that all the four angles thus made are equal. It follows from this, that whenever any two lines cut each other—E Q and R S for instance—the angles at T equal four right angles, no matter whether the lines are or are not perpendicular to each other: and what is more (and what I specially want you to note), the opposite angles are equal—i.e., the two small ones, or the two large ones.

The action of a mitre-block or mitre-box depends upon the principles here laid down, so you see that although few carpenters understand much about mathematics, and simply work as they were taught, without knowing or caring why, those who planned the method of work, and invented mitre-boards and such like devices to shorten work and lessen labour, must have understood a great deal about such things. And so it is generally, as you will find with inventions: things look easy enough, and natural enough, when we see them every day; but it has taken a great deal of thought and sound knowledge to invent them in the first place, and a great deal of practical experience to construct them so neatly. Even a common pin goes through such a number of processes as would surprise you, if you have never been able to see them made.

Look carefully at A. It represents a block of wood, about 1½ or 2 inches thick, and 3 or 4 wide, firmly screwed on the top of a board 1 inch thick. The length is about 18 inches. Two saw-cuts are made with a tenon-saw, right through the block to the board, at angles of 45° with the line a b. These are guides for the saw to work in. The wood to be cut is laid against the edge of the block, and rests on the board, and the saw is then applied in one of the grooves while the wood is being cut by it. Let H be such a piece. If the saw is put in the left-hand slit, it will cut it like y; if in the other, it will cut it the other way, like x; and thus, if a piece is taken off at each end, it will be as you see, ready to become one side of a frame. Now, examine K, which shows all the lines or edges of the mitring-board, as seen from above, with the strip a b sawn across in the line c a. The lines a b and c a cross each other, making the opposite angles equal; and as one angle is 45° the other must be 45° also, so that the right-hand side of the strip is correctly cut. But so also is the other end, and if we turn it over, it will exactly fit, and the two will form two sides of a square. I could prove to you that the second strip contains angles exactly similar to the first, but you ought to be able now to detect the reason for yourself, and I do not want to teach you more mathematics at present, as I am afraid you are tired of these, and will want to go on with the real work of fitting and making. I have, however, said enough, I think, to make you comprehend why the two saw-cuts must be at an angle of 45° with the edge of the top board.

Perhaps you wish to make your own board, however, and would like to know an easy way to get the saw-cuts at the right angle? I shall therefore show you how to do this, but you must be very exact in your workmanship. A B, Fig. 34, is the piece of thick board as seen from above, and close to it is a perspective view of the same which shows the thickness. Set off a distance, A E, equal to A C, and join C E. The dotted line shows you that C E is the diagonal of a square, and the angles at C and E are consequently each 45°; but we do not want this line to end at C, it is too exactly at the corner for convenience. Measure, therefore, a distance, E b and C a, equal, and join a b, which will be the place for the saw-cut; and the other can be marked out in exactly the same way. a x, in the perspective view, must be carefully marked by the help of the square. Take care to mark the line on the bottom board, where the edge of this upper thick piece will fall, and screw the two firmly together. If the edge and face of the thick piece are not truly square to each other, the mitres cut thus will not be correct; but, if all is well made, they may be glued at once together, no paring of the chisel being necessary or desirable.

The mitre-box, Fig. 33, B, is on precisely the same principle, but is chiefly used to cut narrow strips not over 2 inches wide; it should be neatly made of mahogany, half an inch thick. There is also generally made a saw-cut straight across, at right angles to the length of the box or board, which is convenient in sawing across such strips of wood, as it saves the necessity of marking lines against the edge of the square: of course, it is specially used where a large number of strips have to be cut square across. In all these you observe one saw-cut leaning to the right, the other to the left. This is necessary when picture-frames or moulded pieces have to be cut to 45°, because you cannot, of course, turn such pieces over and use either side, which you can do when the piece has no such mouldings.

Several modifications exist of mitring-boards; some arranged for sawing, and some for planing; and where thousands of frames have to be cheaply made, the angles are cut off with circular saws, of which I need not speak particularly here, but which I shall probably have to describe in a future page. In Fig. 34, K, I have shown one corner of a simple picture-frame, covered with what is called rustic work, that is—short pieces of oak, ash, or other wood cut from the tree, left with the bark on, or peeled and varnished. These are nailed on with small brads; and, if well assorted and arranged, this will have a very neat appearance, suiting well for rooms fitted up in oak, as many studies and libraries are. In picture-frames, however, a rebate (called rabbit) has to be made at the back, like L, in which the picture with its glass and back-board has to rest; and this requires a special plane. The front also is always either sloped off or moulded. I shall therefore make this kind of work the subject of my next chapter, and describe the operations of rebating, grooving, tongueing, and moulding.