Spring pin

Spring pins may be used to retain a shaft as a journal in a plain bearing, as a type of key to fasten one shaft to another, or to precisely fasten flat faces of mating parts together through symmetric hole locations.

[1] A coiled spring pin, also known as a spiral pin, is a self retaining engineered fastener manufactured by roll forming metal strip into a spiral cross section of 2+1⁄4 coils.

[2] Coiled spring pins were invented by Herman Koehl circa 1948.

They are also used as pivots and axles, for alignment and stopping, to fasten multiple components together—such as a gear and shaft—and even as ejector pins to remove motherboards from PCs.

These are also often referred to as spirol pins - pronounced ‘spiril’ in the Birmingham area.