Wire binding machines thread two wires through the holes punched in the edge of the pages. The wires are then bent and closed together by the machine after the pages are holed and fed into the wire ring. Usually these machines are used for only 3:1 or 2:1 pitch bindings. A pitch is the number of holes punched per inch (2.54 cm) along the bound edge of the page (i.e., 2:1 pitch is two holes per inch along the edge of the page). Wire binding is generally used to bind larger books or documents.
Thermal binding and perfect binding machines are useful in giving manuscripts a professionally finished appearance. A one piece front and back cover is folded twice and, with thermal binding, the page edges are inserted into the pre-glued spine. The spine is then heated until the glue melts into the edge of the pages. In the case of perfect binding, pages are run across rollers coated with hot glue and inserted into the folded spine. Thermal or perfect bound books and documents present a neat, professional look. This is often the method used for binding paperback books.
Tape machines use a strip of adhesive tape down a pre-folded cover to bind the edge of the pages together. This eliminates the time and expense of heating and drying glue and also produces a tidy, finished appearance.
Strip binding machines punch the edges of the page and run binding strips through the holes. Excess prongs on the strips are cut off by the machine, and the strips are securely sealed with heat. This method presents a finished look since the holes are hidden by the strips, although the bound edge is visible.
Saddle stitching machines, which are costly and complex, are generally used by dedicated printing companies. They punch wire staples through the folded edges of a number of pages. Some saddle stitching machines will both fold and staple in one operation. These machines are most often used to bind magazines and catalogs.
Various other options include click and wire-O binding machines, as well as professional quarter binding, hardcover binding, and sewn binding.