Coil binding
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 andspacing 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 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. 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.
