Modern books are fastened together by sewing; as a rule thread is used, and always in sewing good books. Thread sewing is very much better than wire stitching. In the first place, thread has not the disadvantage of rusting, to which wire is always subject; secondly, thread does not break the paper in the back, as so frequently happens when cheap paper containing much wood fibre is wire-stitched. The greatest advantage of thread sewing over wire lies in the flexibility of the spun thread; with sharp pressure it lies flat in the sheet, whilst wire does not give at all. Besides, it is flexible the whole length, and this adds greatly to the life of the book.

All thread sewing is now done by machinery and is really satisfactory. Only the very smallest job shops sew their books by hand.

The principle of sewing is to fasten each sheet to several cords or bands by means of a long thread running right along the inside of the sheet. These cords give the book its hold to the cover; therefore the more cords used, the more firmly is the book secured to its cover. There are now two methods of fastening the sheets on the cords; first, there is the older method of passing the thread along and out of the sheet, around the cord, and again into the sheet, and repeating the same movement at the next band.

Fig. 21—Arrangement of threads in old style of sewing.

Nowadays, this method is almost entirely discarded. When for special reasons, or on account of its greater strength, it is desired to imitate the old method, the sewing is done on double cords; that is to say, for every cord two cords are stretched alongside each other and regarded as one. This sewing is more tedious, as the thread must take up each cord as shown in Fig. 22.

Fig. 22—Arrangement of threads with double cords.

These somewhat elaborate modes of sewing have been simplified in recent years by making saw-cuts in the back, in which the cords are laid. By this means the sewing thread never actually passes out of the sheet, but is drawn behind the cord lying in the saw-cut and thus holds it.

That is why we "saw-in" our books. The sawing-in is done with a broad saw; the so-called "tenon saw" being the one most generally used. The saw-cut must correspond exactly to the thickness of the cord to be used, should be less deep than wide, and should not take up too much glue when glueing up, as this might easily turn brittle. By inclining the saw to right and left alternately during sawing, the resulting cut will be something like this ¯¯¯¯¯/__\¯¯¯¯¯; this is the best and most usual form. The common practice of widening the cut by means of a coarse file gives a triangular cut like this ¯¯¯¯¯\/¯¯¯¯¯ which is objectionable, as the groove gets filled with glue, thus rendering the thread liable to break. As many cuts must be made in the book as there are cords to be used, besides the so-called kettle stitch at head and tail by which the thread is passed from one sheet to the other. Dividing the back for sawing-in is done by marking off 1 cm. from the head and twice as much from the tail and dividing the rest into equal portions with the dividers. An octavo should never be sewn on less than four cords, and a folio on six. If obliged to use less through low prices, then three must be taken as the minimum number, and that only in exceptional cases. If the books are very small—as, for instance, prayer-books and hymn-books less than 7 cm. in height—it may then be permissible to sew on two cords. The division for the different sizes for sawing-in is made as shown in Fig. 23.

Fig. 23—Divisions for sawing-in.

The saw-cuts at the kettle stitch are less deep and quite narrow; they only mark the place where the thread is to pass in and out.

It may be wondered why the distances between the cords, when using four or six, are unequal; the reason for this will be explained when we come to the sewing of such sizes.

In sawing-in, the batch to be sawn is knocked up head and back and put between two boards—if the volumes are thin, several may be laid together—so that the back projects about 1/2 cm. beyond the edges of the boards. The first and last sheet of each volume have previously been laid aside, as these, with one exception, are not sawn-in.

Books and boards are now clamped in a small hand-press, which is screwed up by hand only. For convenience of working, the press with the screws is laid flat upon the table, so that the nuts are against the table edge. The press is propped up at the back by the press-jack. The divisions for the cords are marked on the back with a lead pencil after measuring with the dividers, and the cuts made according to the markings. If several volumes of the same size are to be sawn-in, the top sheet of the first batch sawn is used as a guide for marking the others, thus saving the work of measuring each one with the dividers. Where much sawing-in is done, a sawing-in machine is employed. The sheets are placed, backs downwards, in a moveable box, which is led over a system of circular saws.

After the work of sawing-in, the first and last sheets are replaced, the volumes again collated, and the end papers put in place; the sheets are now ready for sewing.

End papers are the blank leaves which the binder places at the beginning and end of a book. They vary according to the style of the book. Every end paper consists of a "fly leaf" (this lies over the title page in the book), the "paste-down," and in most cases of a "tear-off." For the stronger end papers and in half-leather bindings a cloth joint is used. Whilst dealing with these end papers, we must not forget the narrow guard; it is worked on the prepared end paper (as will be shown later) by folding over, and serves to enclose the title or end page with which it is sewn. The words joint, guard, and swell may here be more clearly explained, as they are used very frequently in the bindery. In the first place, we call the part where back and cover are joined by a sort of hinge "the joint," also strips of leather, cloth, &c., used for making this part are called "joints"; secondly, the slightly raised part of the back, caused by pressing or sewing, is shortly called "the swell"; and any strips of linen or paper fastened into the back of the book for hingeing maps, plates, &c., are called "guards."

For use as end papers, a paper must be selected which suits in quality and tone the printed paper. Nothing shows lack of taste more than the use of a blue end paper with a paper of yellow tone. For both back and front a double sheet is necessary and is cut the required size. A paper guard, about the width of three fingers, is made from a piece of stout waste paper and pasted on a narrow margin at the back of the double leaf, in order to protect it in the joint and also for fastening on the cover. If there are single leaves to be used up, two of these might be pasted to each other narrowly on the back and upon this the guard; this is the so-called double end paper.

If instead of these only a single leaf is taken, then we have a single end paper; this is used for cheap school books and generally at the back only.

The accompanying sketch shows both these end papers with the small guard already folded. This folding of the guard is not very easy for the beginner. The leaf is placed face upwards, square in front of the worker, and a very narrow margin at the back edge bent upwards about 3 mm. in width, the forefinger and thumb of both hands shaping and bending the guard, working from the centre to the ends.

Fig. 25—Suggestions for single and double end papers.

Should the sheet from which the end papers are made be a little wider than required for the end papers, the tear-off may be folded at the same time; with double end papers, the leaf which is to be pasted down later is inserted between fly leaf and tear-off, and therefore is called "insertion."

Fig. 26—Suggestion for double end paper with tear-off.

If the end papers are to have a cloth joint it must be placed within the two leaves or, better, pasted in face inwards. Double cloth joints are no longer used in printed books, as they make the end papers too thick, and in the subsequent rounding the first sheet is apt to break. The joint is here also folded on as before.

Formerly, when linen joints were used, the end paper was simply made by inserting the strip of cloth and hingeing on the outside leaf about 1 cm. from the fold. This, however, has many disadvantages, therefore the end papers are made as explained, then carefully tearing off the outside leaf in the back in pasting down and cutting it as required it is pasted on to the board, as will be more fully explained under "pasting down."

The French paste a double leaf before the first and last sheets after having pasted a covering leaf around these.

For extra work, the following style of end paper is the best; it is used in England for all high-class work, and in Germany also it has been adopted by all the first-class firms.

The end papers consist merely of single leaves the size of the sheet. These are fanned out at the back to make a small margin and pasted. The first leaf is then pasted down on the end-paper sheet so as to leave a margin of about 2 mm.; the second leaf is pasted level with the back. All end papers are proceeded with in the same way.

If these are to have a cloth joint it must be pasted on the outside also only 2 mm. wide. When the end papers are dry, they must be stitched down along the back, 2 mm. from the edge, with the sewing-machine adjusted to its longest stitch. It is unnecessary to knot the ends of the thread—they are cut clean off. When there is no sewing-machine, the volumes must be overcast by hand. This overcasting is done by inserting a fine needle near the back of the knocked-up sheets from above and drawing the thread almost quite through, the second and following stitches all being made from above. The thread would then appear as in Fig. 27.

Fig. 27—Overcast end paper.

These end papers are made up before sawing-in and sawn in with the book, and when it is not possible to stitch them with the machine they must be sawn in before overcasting, or the sawing would cut the threads.

Now for the sewing. We stretch the requisite number of cords, which are secured to the hooks at the top by a simple loop which is easily undone as soon as it is taken off the hook. At the bottom a double loop is made, through which a key is passed so as to hold the stretched cord underneath the moveable board.

The length of the cords is regulated by the thickness of each book, and as it is possible to sew a number of books at the same time when they are all sewn the same way, the length of the cords is regulated accordingly; it also depends upon the kind of books to be sewn. Cheap books get 3 cm. for every cord on each side more than the thickness of the book, that is 6 cm. plus the thickness of the book. School books get still shorter cords. For extra work, where the ends of the cords are laced through the boards, one should allow double. It is easy to calculate the length required for a single volume, but rather difficult for a batch of books varying in thickness; it is then better to measure. For example, suppose we have to sew a batch of six books, all differing in thickness but measuring in all 25 cm. high; we would allow for cheap work: 6 vols., each taking 6 cm. extra lengths = 36 cm. + total height, 25 cm., making 61 cm.; for extra work: 6 vols., each taking 12 cm. extra lengths = 72 cm. + 25 total height = 97 cm. length of cord.

The collated batch of books is laid on the bed of the sewing frame as in hollÄndering (Fig. 17), the sheets taken hold of in the same way, and laid open for sewing. Of course the cords are adjusted to the saw-cuts, and it is better to push them more to the right than to the left, so as to give the left arm full play. Here also, as in hollÄndering, the left hand does the work behind the cords inside the sheet, whilst the right inserts the needle from the front and again brings it out.

Fig. 30—Suggestion for sewing on four cords.

Fig. 31—Suggestion for sewing on six cords.

The first and last sheets—called end sheets—are sewn a little differently from the others, as the needle is here not inserted and drawn out exactly at the cord but at a little distance from it so as to allow them to be adjusted afterwards. Sewing[1] with us is invariably begun with the last sheet at the right, working on to the left, and reversing the process with the following sheet, and so to the end, so that the thread one way passes from and the other to the worker. With all other sheets, excepting the end sections, the thread is inserted at the kettle stitch and brought out at the next cord, round the cord, and inserted at the same hole, to be brought out again at the next cord, and so on till the thread comes out at the other kettle stitch and is inserted in the next sheet to go through the same process. With books sewn on four cords, it is allowable to skip one of the two middle cords alternately, so that each time the thread passes on to the right the right middle cord is skipped, and the left is skipped when the thread passes in the opposite direction. This facilitates and shortens the work without taking away from durability or quality. Books on 6 cords may be treated in the same way; the right and left of each pair of cords may be skipped alternately. It was for this reason that we paid attention to the distribution of the cords on the back when sawing-in (see Fig. 23).

This method of sewing is known as "end to end," in contradistinction to "two sheets on." The former is the better method and is essential for valuable books, unless the sections are exceptionally thin. The latter is "good enough" (i.e., not worth much) for the trade and cheap work. As far as strength is concerned it would do, but a book sewn in this way does not swell sufficiently in the back to make a proper backing groove.

It is an old rule in bookbinding that each sheet after it has been sewn should be pressed down with the needle so that the backs of the sheets lie close and firm together; this is called "pressing down." Should this, however, not be sufficient, the back must be knocked firm from time to time with the dividers or a rule.

The first and last sheets must be fastened to the one following and preceding respectively; but in the course of the sewing this enchaining to the preceding sheets—the so-called kettle stitch—is only necessary in the case of very thick sections. It is done by passing the needle through and bringing it out between the two preceding sheets at each end and thus chaining on the then top sheet to the one lying underneath.

The two-sheets-on sewing is done by laying open the second sheet on top of the first after making the first stitch in the first sheet and then passing the needle through the second sheet, then the third stitch is made in the first sheet and the fourth in the second sheet. One length of thread is used for the two sheets. Where the sheets have not been cut open, the left hand lightly takes the sheets in turn where they have been cut, a folder is placed in the middle and is shifted from one to the other as required. The process is the same whether there are only three cords or even six.

Fig. 32—Suggestion for sewing two-sheets-on.

It has already been said that several volumes of the same kind can be sewn on top of each other on the sewing frame; in this case the volumes must be separated from each other after the sewing is completed.

The free ends of the cords are untwisted so that they may be scraped open more easily afterwards, and then one volume after another is drawn along the cords to the ends until they are twice the length of the free cords away from each other, which, of course, will vary according to the subsequent style of binding.

So then we allow 6 and 12 cm. according to circumstances; but this length is curtailed to 3 cm. in the cheap school books, because the shorter the cords the quicker they are scraped open. Every cord is cut in the middle between the books with the shears, thus separating each volume from the other. The strands of the loose ends of the cords are now completely untwisted by inserting the cord in the groove of the scraper and repeatedly rubbing it up or down with the back of a knife.

After scraping the cords, the end-paper guards are always pasted down; the book is laid with the back to the front edge of the table, the first sheet with the end paper is turned downwards, the end-paper guard is bent up a little so that it stands away from the sheet, paste it neatly and carefully, close the section and adjust it so that the sheet in the end paper is level with the others, but not the end paper itself—this must project a little at the back. When only one finger is required for pasting it must be the middle finger, so that the forefinger is free from paste and ready to take hold of anything.

If stitched end papers are used for extra work, a sheet of paper is laid on the second sheet so as to leave 3 mm. free, paste this strip and bring down upon it the once-more closed first sheet, taking care to square it at the outside with the body of the book.

The folder should be brought down firmly over the outer sheets after pasting down so as to ensure the paste sticking.

If the pasting-on of the joints is not properly carried out, the result will be that in most cases the book opens badly when finished.

In half-cloth or other simple bindings, the scraped cords may be pasted on at once. Bring a little paste (about the size of a pea) upon the point of a folder under the slightly raised cord, pasting the latter evenly and neatly upon the paste-down of the end paper so that the pasted-down strands of the cord lie like a feather. To prevent the pasted cords sticking to each other, the books are piled up back and front until dry. In extra work, the cords—which are also longer—must by no means be pasted on; a piece of waste paper or a cover the size of the sheet is pasted outside the sections under the cords, level with the backs. This serves partly as a protection for the end papers and partly to make a good joint when covering.

The volumes so prepared are now glued up. They must be knocked up at head and back; they are then placed with the backs outwards on a board specially kept for this work—the glueing board—with the fore-edge of which they must be exactly level. On top must be placed a smaller board or a heavy piece of iron, likewise level with the book. The book backs are thus held firmly between the glueing boards, the left hand holding them firmly by pressing on the top, the right hand glueing the backs with very hot but not thick glue; rub this well in with the point of a hammer, and after having firmly squeezed the glue out of the brush, use it for taking off the surplus glue from the backs. An old trick of the bookbinder is to heat the hammer for this work. It is a bad plan to give the back a thick coating of glue and then allow it to dry, because it at once becomes brittle. Some experienced workers place the books between the glueing boards so as to leave about 1 cm. projecting, as it is thought that the glue thereby gets better between the sheets; but this method is out of date and is of no special value. It is, however, of great importance that the glued book should be laid so that it is truly square at the head as well as the back, for if this is neglected no amount of trouble will save the book from being cut out of shape.

Before passing on to the next chapter we have still to mention the mechanical contrivances for sewing. For small as well as large binderies, machines have been invented both for wire stitching and thread sewing; the former are more generally used, the latter not being sufficiently perfect in construction to meet all demands for speed and accuracy. Then also the method of fastening the book in the cover differs so much from the traditional method that we must still hope for improvement. When this comes to pass, this machine will then supersede the wire-stitching machine, with all its unavoidable disadvantages. The working of the machines is so simple that they are attended to almost entirely by girls. We refrain from giving descriptions of mechanical appliances within the limits of a short treatise, as any day may bring forth new inventions which are certain to effect great changes in this department. Besides these costly appliances there are also simpler sewing-machines for small shops, by which books are sewn in very simple fashion over steel needles, by means of which the cords may afterwards be drawn along.

As these machines demand very large saw-cuts, they can only be used for trade work and any cheap lines. We only mention them to draw attention to their existence. Unprinted paper and music are sewn on tapes as well as cords. This method of sewing is described in Chapter IX.