Milling. The spines of books can be cut away on a milling machine to prepare them for double-fan adhesive binding or oversewing. The machine clamps the text block, spine down, and moves it over a series of rotating blades that cut away approximately 1/32 to 1/16 inch of the binding margin, thus removing old adhesive, thread, staples, and/or the folds of signatures. After milling, a text block is comprised of loose leaves.
Rounding is the process of hammering or manipulations of the textblock spine into a convex shape preparatory to backing. Rounding diminishes the effect of swelling caused by the thickness of the sewing threads or the application of glue from an adhesive binding. It also helps to prevent the textblock spine from falling into a concave shape after years of use or of standing upright on a shelf.
Backing is the process of shaping a ridge or shoulder on each side of the spine of a text block after rounding it, and prior to lining it. Backing accommodates the thickness of the boards, and provides a hinge along which they swing. Backing also helps to prevent the spine of the text block from collapsing into a concave shape over time.
Flat Back: Some collectors prefer the look of a flat back book. Flat back books are not rounded and backed.
Buckram Cloth is a heavy-weave cotton cloth filled, impregnated, or coated with different compounds (mainly, starch and pyroxylin but also other materials) to enhance body, finish, and durability.
Bonded Leather is a material made of varying degrees of genuine leather combined with other substances to give the appearance of leather at reduced cost.
Imitations Leather is a lighter weight buckram like material offering a textured finish to enhance the beauty of the bound volume without compromising strength or integrity. (100% cotton)
Arrestox Material is a light weight cotton cloth material impregnated with aqueous acrylic.
Headband is a small ornamental band, generally of mercerized cotton or silk, which is glued on the head as well as the tail of the text block spine of a book.