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.