Coil Binders — Punching for Plastic Coil

Punching for spiral is not always so easy. If you have a plastic coil machine that can manipulate the spiral prior to insertion, consider yourself lucky; most cannot. Therefore you are stuck with whatever pitch the spiral may be. Let's use the industry standard of the 4:1 pitch.

In days gone by metal spiral binding used a 4:1 (or in Europe a 6mm center-to-center) pitch. But back in those halcyon days, the holes were small, 9⁄64˝ (3.5mm). They only needed to accommodate a very thin gauge of wire. Plastic coil gauges are much thicker, some as thick as 1⁄8˝ (3mm) and 9⁄64˝ holes just won't do. Standard plastic coil gauges range from .063˝ to .085˝ (1.5-2mm).