Spirol Pins - Imperial
Similar in design to a standard spring pin, Spirol pins are made from thin metal that has been coiled into a tube shape. Spirol pins are stronger than normal spring pins.
With coiled Spirol pins, the stress loaded on to the pin during the installation process (when the pin is compressed) is distributed equally throughout the whole cross section of the pin. This load spreading feature helps the pin to absorb vibrations and adds strength are flexibility.
Spring pins are a self-locking fastener that use tension to hold two or more components together. The pin is slightly larger than the hole that it is being introduced to, so that once inserted into place the outside walls of the sprung steel pin exert pressure and hence grip the hole, holding the pin and the components in position.
Imperial is a generic term used to describe threads that were in common use before the metric standard was adopted. Types of imperial threads include UNC, UNF, BSW, BSF, BA etc. Many of these thread types are still commonly used today.