Page:The Art of Bookbinding, Zaehnsdorf, 1890.djvu/57

Rh the same time, by fastening other pieces of leather for the head and tail, and making it the catch-up stitch as well. When the head-band was worked in sewing, the book was, of course, not afterwards cut at the edges. When this was done, wooden boards were used instead of mill boards, and twisted leather instead of cord, and when the book was covered, a groove was made between each double band. This way is still imitated by sticking a second band or cord alongside the one made in sewing, before the book is covered. The cord for flexible work is called a "flexible cord," and is twisted tighter and is stronger than any other. In all kinds of sewing I advise the use of Hayes' Royal Irish thread, not because there is no other of good manufacture, but because I have tried several kinds, and Hayes' has proved to be the best. The thickness of the cord must always be in proportion to the size and thickness of the book, and the thickness of the thread must depend on the sheets, whether they be half sheets or whole sheets. If too thick a thread is used, the swelling (the rising caused in the back by the thread) will be too much, and it will be impossible to make a proper rounding or get a right size "groove" in backing. If the sections are thick or few, a thick thread must be used to give the thickness necessary to produce a good groove.

Flexible sewing.

If the book is of moderate thickness, the sections may be knocked down by occasionally tapping them with a piece