The Art of Bookbinding/Chapter 12
CHAPTER XII.
Backing.
The boards required for backing, called backing boards, should always be the same length as the book. They are made somewhat thicker than cutting boards, and have their tops planed at an angle, so that the sheets may fall well over.
Hold the book in the left hand, lay a board on one side, a little away from the back, taking the edge of the top sheet as a guide, the distance to be a trifle more than the thickness of the boards intended to be used. Then turn over the book, with the backing board, holding the board to the book by the thumb, so that it does not shift, and lay the other board at exactly the same distance on the other side. The whole is now to be held tightly by the left hand and lowered into the press. The boards may 
Backing Hammer. possibly have shifted a little during the process, and any correction may now be made whilst the press holds the book before screwing up tight, such as a slight tap with the hammer to one end of a board that may not be quite straight. Should the boards however be not quite true, it will be better to take the whole out and readjust them, rather than lose time in trying to rectify the irregularity by any other method. If the rounding is not quite true it will be seen at once, and the learner must not be disheartened if he has to take his book out of the press two or three times to correct any slight imperfection.
Before Backing.
After Backing.
The book and boards having been lowered flush with the cheeks of the press, screw it up as tightly as possible with the iron hand-pin. The back of the book must now be gently struck with the back of the hammer, holding it slanting and beating the sheets well over towards the backing boards. Commence from the centre of the back and do not hit too hard, or the dent made by the hammer will show after the book has been covered. The back is to be finished with the face of the hammer, the sheets being brought well over on the boards so that a good and solid groove may be made. Each side must be treated in the same way, and have the same amount of weight and beating. The back must have a gradual hammering, and the sheets, when knocked one way, must not be knocked back again. The hammer should be swung with a circular motion, always away from the centre of the back. The book, when opened after backing, should be entirely without wrinkles; their presence being a sign that the workman did not know his business, or that it was carelessly done. Backing and cutting constitute the chief work in forwarding, and if these two are not done properly the book cannot be square and solid—two great essentials in bookbinding.
Backing flexible work will be found a little more difficult, as the slips are tighter; but otherwise the process is exactly the same, only care must be taken not to hammer the cord too much, and to bring over the sections very gently, in order not to break the sewing thread.
Two-edged Backing Boards.The backing boards may be replaned from time to time, as they become used, but boards may be had having a double face of steel to them; these may be used from either side. The edges of the steel must not be sharp, or they will cut the paper when backing. The ordinary boards may also have a face of steel screwed to them, but I prefer to use the wood—one can get a firmer back without fear of cutting the sheets.
There are several backing machines by different makers but they are all of similar plan. The book being first rounded is put between the cheeks, and the roller at the top presses the sheets over. I am sorry to say that a great number of sheets get cut by this process, especially when a careless man has charge of the machine.