UNDERSTANDING THE STATE-OF-THE-ART IN NON-LOCKING FOLDERS
Although their exact history is unclear, the earliest known folding knives date back to the Roman Empire around 600-500 B.C. Consisting of simple blades that folded into crude handles, early folding knives had no locks and remained open during use only by the friction of the joint mechanism.
Centuries later, these “friction folders,” as they are now known, evolved to become more refined, safer, and more reliable. One of the primary improvements to their design was the addition of a tab that extends from the tang of the blade, much like the extended tang of a traditional straight razor. In the open position, this tab lays against the back of the handle and acts as a stop to restrict the opening arc of the blade. When the knife is gripped in the hand, pressure from the user’s grip holds the tab in place to keep the blade from closing during use. When the knife is closed, the tab protrudes from the front of the handle and can also be used as a lever to help open the blade.
As folding knives and metallurgy evolved, knifemakers began to incorporate mechanical elements into their designs to hold the blade in the open position. This gave rise to the most common form of non-locking folding knife: the slipjoint.
The defining characteristic of a slipjoint knife is the inclusion of a flat spring in the back of the handle. This spring applies constant pressure against the tang of the folding blade, which features a flat spot on the edge side and a shouldered flat spot on the spine side. In the closed position, the spring’s pressure on the edge-side keeps the blade safely closed. When the blade is opened, the shoulder of the tang contacts the front of the spring and acts as a stop. The spring’s pressure on the flat area of the tang adjacent to the shoulder holds the blade open and allows it to be safely used for most cutting chores. Perfectly suited to the vast majority of cutting tasks, slipjoints are socially acceptable and legally permissible almost everywhere.
Spyderco’s expressions of the slipjoint concept include our Trademark Round Hole™, which not only makes them instantly recognizable as members of the Spyderco family, but is also much more user friendly than a traditional nail nick for two-handed opening of the blade.
Spyderco’s SLIPIT™ knives integrate an improved notched-joint pivot mechanism, a pocket clip for convenient carry, and one-handed opening operation via our Trademark Round Hole. These knives represent a significant evolution of slipjoint design and bring the non-locking folder into its own as a modern everyday carry cutting tool. SLIPITS also feature an index finger choil that provides a comfortable purchase for the index finger during use and help prevent accidental closure of the blade.
Spyderco’s non-locking folders redefine the state-of-the-art in knifemaking tradition and provide knife users worldwide with cutting tool options that are legally permissible and socially acceptable.