Understanding mechanical binding

There are many ways of mechanically binding paper together. We’ll focus on the methods most used in commercial and digital shops: Spiral, Wire and Cerlox Binding.

Spiral binding

Spiral Binding (aka coil binding) uses a circular plastic coil that is inserted into the spine of the book block through circular holes punched into the paper to create a bound, lay-flat book. The punch creates a circular or oval hole pattern. Oval hole patterns are becoming more popular because they make it easier to insert the coil into thicker books. The coil is inserted with the aid of a rubber-roller-powered device. Spiral has become the most popular form of mechanical binding for a number of reasons. The spiral can be easily inserted into any size of book and then trimmed to its final size, thus eliminating the need to purchase the exact length required. A full range of colours adds additional dimension to the design and can be matched to a specific corporate colour scheme. Plastic coil is low-cost and available from 6mm sizes up to 50mm. This allows binding books up to 2″ thick (or containing about 460 sheets).

Pros:

• Single-punch pattern can be used for all thicknesses of books

• Wide range of colours are available

• 12″ and 36″ lengths can be easily cut to required length

• Allows book to lie flat on a table

Cons:

• Pages cannot be removed or new sheets added

• Coil is flexible and may not support the spine of large books, especially ones that contain heavier coated paper

Wire binding

Also called Wire O or Twin Loop Binding, it’s available in two different pitches – 2:1 – 2 holes per inch and 3:1 – 3 holes per inch. 2:1 places two holes across the spine of the book block and allows binding from ¼” up to 1 ¼” thickness. 2:1 pitch is almost always used for thicker substrates as the gauge of the wire is also thicker. 3:1 wire is used for all books up to 9/16″. Wire binding is most often used for calendars – as well as reference books that combine light and heavy substrates. Wire-bound hole patterns are square and require the wire spine to be inserted and then crimped or squeezed closed with an adjustable crimper. Additionally, a wire bound document can also contain a plastic hanger for such applications as calendars. Wire-bound documents also have the ability to lie perfectly flat on the table and also allow for a 360-degree rotation of the paper.

Pros:

• Wire is strong and will support thicker books that contain thicker stocks

• Wide range of colours are available

Cons:

• Must either be cut to proper length or order custom dimensions

Cerlox binding

Cerlox Binding (aka comb binding) uses a plastic strip that has teeth on each side that close together to lock the book block into a bind. Cerlox is available in standard sizes of 19 rings for letter size and 21 rings for legal size. Spines are available from 3/16″ up to 2″ with a capacity of 425 sheets. Cerlox hole patterns are rectangular and the plastic binding strip or “combs” need to be opened with a special spreading device so the book block can be inserted over the plastic spine. The appeal of Cerlox is that the spines can be printed on, thus showing the title of the work. Different colours are available but black and white are the two most popular.

Pros:

• Lay-flat properties

• Spines or combs can be printed on

• Individual sheets can be added or removed

Cons:

• Not as aesthetically appealing

The machines: How it’s done

While many printers use large machines for mechanical binding, the range of smaller machines on the market has increased, especially units that have changeable punch patterns (dies).

Low-volume machines

These give you the ability to produce one type of bind and usually include a small finishing attachment to complete the process. For example, a spiral machine has a small electric inserter on the top, whereas a wire or cerlox machine includes a small comb opener or wire crimper mounted on the top. Typically, these punches are operated with a manual hand lever or electric foot pedal and can punch from 10 to 20 sheets per lift.

Mid-range machines

They’re the most popular type of mechanical binding punch. Electrically operated, they allow the punching of up to 55 sheets per lift, are foot-pedal or hand-control operated, and include a die system that can be changed to allow the punching of different hole patterns. All of the final coiling or crimping is completed after the punching process using line inserters or crimpers. Coil inserters that have integrated cutters and crimpers, or electrically powered crimping machines, are the most popular for high-production workflows.