Hunt sold the rights to his invention outright for $400, forfeiting any future royalties on what became one of the most widely used objects in the world. The design, a single piece of wire bent into a coiled spring with a clasp guard, has remained essentially unchanged for over 170 years.
Walter Hunt was a serial inventor with a habit of never quite cashing in on his ideas. He had already devised a working sewing machine years earlier but suppressed it, fearing it would put seamstresses out of work, effectively handing the credit and fortune to Elias Howe and Isaac Singer instead.
According to popular accounts, Hunt owed a friend $15 and, twisting a piece of wire in his workshop to figure out how to pay it back, spent about three hours fashioning the coiled safety pin with a clasp that shielded the sharp point. He filed for a patent and then promptly sold the entire rights for $400, enough to cover his debt and then some, but a fraction of what the invention would eventually be worth as it went into mass production worldwide.
The safety pin's genius lay in its simplicity: a single continuous piece of spring steel wire, requiring no separate parts, that could be manufactured cheaply and at enormous scale. It became a staple of clothing repair, cloth diapering, and eventually punk fashion, all traceable to a few impatient hours of wire-twisting by a debt-pressed tinkerer in New York City.
Key people: Walter Hunt