What’s the Hole in a Safety Pin For?

a coil, that is where that hole lives.

The coil creates tension. It’s this tension that keeps the pin shut when you close it, so it doesn’t spontaneously pop open and stab you in the thigh during a meeting. The clasp part? That’s all safety stuff — hence the name — so the very sharp end is neatly tucked out of the way. But back to that coil. The shape of it, see, is not because everything inside needs to be kept springy.

So What Is That Tiny Hole Actually For?

Here’s the secret: the hole in a safety pin is part