the coil isn’t a leftover from manufacturing or a decorative feature. Instead, it’s a fundamental part of the safety pin’s spring mechanism.
During production, the hole serves as an anchor point for the wire. The wire is threaded through this tiny opening as it’s coiled, which helps maintain consistent tension throughout the pin. Without this hole, the wire would not hold its tightly wound shape, and the spring would be far less effective. The coil might become loose over time, reducing the pin’s reliability and possibly causing it to fail
