Coil binding, also known as spiral binding, is a commonly used book binding style for creating documents, reports, presentations and proposals. This binding style is known by a number of names including spiral coil, color coil, colorcoil, ez-coil, plastic coil, spiral binding, plastikoil and coilbind. Documents bound with helical coil (usually called spiral

Spiral

In mathematics, a spiral is a curve which emanates from a central point, getting progressively farther away as it revolves around the point.-Spiral or helix:...

 coil) can open flat on a desk or table and offer 360 degree rotation for easy note taking. This binding style is durable and is often used for documents that need to be mailed. Spiral coil binding spines are also available in more colors and sizes than other binding styles.

Coil binding hole patterns

The most common hole pattern used with coil binding is a 4:1 pitch hole pattern (6mm outside the US). This simply means that there are four holes per inch on the edge of the document. The holes for this style are usually either round or oval shaped and depending on the size and spacing of the hole pattern, there will be 43 or 44 holes on an eleven inch binding edge. Supplies for binding documents with 4:1 pitch spiral coil are available in sizes ranging from 6mm up to 50mm in diameter. This allows for binding documents that are up to two inches thick.

Although not as common as four to one pitch coil, some printers and binderies prefer to use 5:1 pitch coil (5mm overseas). With five holes per inch, 5:1 pitch coil is more tightly wound and provides a neat and tidy appearance. However, the tight spacing of the coil and the smaller size of the holes used by this pattern limit the size of spines that are available. Five to one pitch spiral coil is available in diameters ranging from 6mm up to 25mm. This means that documents larger than one inch thick can not be bound using this hole pattern.

3:1 pitch spiral coil is less common than either 5:1 or 4:1 pitch coils. It is designed for use with the hole pattern used in Wire Binding

Wire Binding

Wire binding is one of the most popular commercial book binding methods used in North America and is known by a number of different names including twin loop wire, Wire-o, double loop wire, double-o, ring wire and wirebind. With this binding method, users insert their punched pages onto a "C"...

 or with GBC Proclick. Three to one pitch spiral coils are slightly easier to use for large diameter books because there are fewer holes to insert the coil through. Supplies for this hole pattern are available in sizes ranging from 6mm up to 50mm.

2.5:1 pitch coil is also known a 0.400 pitch coil and is used with a hole pattern that has 2.5 holes per inch. However, many users choose to use this hole pattern with the hole pattern that is produced for 2:1 pitch Wire Binding

Wire Binding

Wire binding is one of the most popular commercial book binding methods used in North America and is known by a number of different names including twin loop wire, Wire-o, double loop wire, double-o, ring wire and wirebind. With this binding method, users insert their punched pages onto a "C"...

. This type of spiral coil uses a larger filament diameter and is specifically designed for binding thick documents. Spirals in this pitch pattern are available in diameters ranging from 20mm up to 56mm. This means that 2.5:1 pitch coil can be used to bind documents that are thicker than any of the other pitches of spiral coil.

Coil

One of the strengths of spiral coil binding is that the supplies are available in a variety of lengths. Most users purchase spiral coils in twelve inch lengths. This spine is inserted onto an eleven inch document and the excess length of coil is cut and crimped at each end of the book. However, the extrusion

Extrusion

Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section...

 process for creating spiral coil binding elements allows them to be created in virtually any length. Many binderies and print shops choose to purchase coils in 36" lengths in order to have the flexibility to bind custom document sizes and to reduce waste. For binding documents shorter than eleven inches it is also possible to purchase shorter lengths of spiral coil in order to save time and money.

Spiral coil binding supplies are also available in a wide variety of colors. In fact there are more than sixty standard colors available for binding documents with spiral coil. This makes spiral coil binding an excellent choice for marketing agencies and design firms that want to match the spine of the document to a specific color palette. It is even possible to get a PMS color match for organizations that want their spines to match the exact colors used in their printed materials.

Coil binding spines are normally measured in millimeters and not inches. Coils are available in sizes as small as 6mm (1/4") and as large as 56mm depending on the pitch of coil chosen. However it is important to note that binding thick documents using spiral coil can be difficult. When a large document is punched for coil binding the path through the holes will be straight. However, the coil binding spines are curved. This means that it is necessary to shape the spine of the document into a curve in order to allow the coil to travel smoothly through the holes. Special tools are generally used for this purpose.

Coil binding equipment

There are three important pieces of equipment for binding documents with spiral coils. First, a punch creates holes along the edge of the document. Second, a coil inserter spins the coils through the holes. Third, a pair of coil crimping pliers or a crimping machine is used to cut off the excess coil and crimp the end to prevent the coil from coming loose from the document. Light volume or personal users may choose to buy a single machine that does all of these features or may even choose to spin the coils onto their books by hand. Higher volume users will often choose to separate these three functions to help increase productivity.