But the hole does not stop being useful once the pin is formed. Once the coil is created, that same hole continues to play an active role in maintaining the spring tension that keeps the pin snapped shut. That tension is the entire reason a safety pin holds closed instead of popping open in your pocket and turning into a hazard.
The coil stores mechanical energy when the pin is opened. When you release it, the coil returns to its original position — snapping the sharp tip back into the clasp with that satisfying click. The hole in the center of the coil helps maintain even pressure across the entire spring, ensuring it retains its elasticity after dozens, hundreds, or even thousands of open-and-close cycles. Without this structural support, the coil could lose tension over time, making the pin unreliable and potentially unsafe.
A Brief History of the Safety Pin
The modern safety pin was invented in 1849 by an American mechanic named Walter Hunt, who was simply trying to pay off a $15 debt. Using nothing more than a piece of brass wire, he twisted it into the shape we still recognize today — a sharp point, a protective clasp, and a spring coil in between. He patented the invention and sold the rights for just $400, never imagining it would become one of the most universally used tools in human history.
