Spyderco Byte July 2021 - Unlocking the History of non-locking Knives

Unlocking the History of non-locking Knives​

Edge-U-Cation®​

Non-locking pocketknives were the first knives to combine the convenience and ease of carry of folding construction with the utility of a sharp cutting edge. The oldest known folding knife, the Hallstatt Knife, was a member of this breed. Named after a village in present-day Austria where it was found, it has been dated by archeologists to approximately 500 to 600 BC, so folding knives have clearly been serving mankind for more than 2,500 years.

The earliest folding knives were friction folders, as they relied only on the friction of the handle around the blade pivot to keep the blade open during use. Some friction folders also had a tab that extended from the tang of the blade, similar to a traditional straight razor, that indexed against the back of the handle. When the open knife was gripped, pressure from the user’s hand would hold the tab in place to keep the blade from closing.

As knife design and metallurgy evolved, the slipjoint emerged as the most common type of non-locking folding knife. When the blade of a slipjoint is opened, a spring in the back of the handle applies pressure against a flat spot on the tang of the blade. This spring tension holds the blade firmly open during use but does not mechanically lock it. Excellent tools for most cutting chores, slipjoints are also socially friendly and legally permissible almost everywhere.

SLIPIT™​

Led by the pioneering UK Penknife, Spyderco’s distinctive SLIPIT breed of knives revolutionized the concept of non-locking folders by incorporating a pocket clip for convenient carry and one-handed operation via our Trademark Round Hole. These features allow SLIPITs to be much more accessible and convenient than classic pocketknives and spare users the frustration (and broken fingernails) of traditional nail nicks.

SLIPITS are also unique in that they feature “notched-joint” mechanism and a forefinger choil. Unlike the flat contact surfaces of the spring and tang of a slipjoint, the blade of a SLIPIT features a shallow notch and the backspring an extended lug. Although they resemble the lock interface of a back lock mechanism, the rear corner of the notch is purposely radiused. This clever design provides greater tension on the blade than conventional slipjoint mechanisms but does not mechanically lock the blade open.

The forefinger choil at the juncture of the handle and blade provides a comfortable purchase for the index finger during use. This forward grip provides enhanced control and allows the finger to serve as a natural “stop,” helping to prevent accidental closure of the blade during use.

CLIPJOINT™​

Although specifically created to comply with UK knife laws, the UK Penknife also gained favor in many other European countries. As the laws of those countries changed to become increasingly restrictive, Spyderco pivoted to keep pace. When Denmark prohibited one-hand-opening non-locking knives, we created the Spy-DK™—a variation of the UK Penknife with a much smaller Trademark Round Hole. The smaller hole still served as a proud symbol of our trademark and, when pinched between the thumb and index finger of the opposite hand, allowed easier blade opening than a nail nick. It was not large enough, however, to provide a purchase for one-handed opening. This hybrid, non-locking, clip-carry folder was known as a “ClipJoint™”—a term that never enjoyed broad usage but is an undeniable part of Spyderco history.

OTHER NON-LOCKING SPYDERCO KNIVES​

In addition to the major categories of non-locking folders described above, over the years Spyderco has also offered other unique non-lock-blade designs. Our smallest knife—the Bug™—along with its larger counterparts the HoneyBee™ and Grasshopper™ are our expressions of the classic slipjoint concept.

In 2007, we introduced the T-Mag™ folder. Designed by renowned custom knifemaker Ralph Turnbull, it incorporated a neodymium rare-earth magnet in the spine of the handle. The magnet’s powerful pull replaced a traditional backspring to keep the blade open during use, giving this knife an exceptionally smooth action.

Two years later, we released the Terzuola SLIPIT, designed by the “Godfather” of tactical folding knives, Bob Terzuola. This unique knife was distinguished by Terzuola’s Ball Joint non-locking mechanism, which used integral tabs in the knife’s stainless steel liners to serve as springs. Ball bearings set into these springs indexed holes in the tang of the blade to hold it closed and open, much like the detents of LinerLock and Reeve Integral Lock (R.I.L.) mechanisms. A similar detent-based non-locking design is also used in Spyderco’s Serge Panchenko-designed Dog Tag Folders.

Finally, our popular Roadie™ series of knives combines Spyderco’s improved notch-joint mechanism with a bilateral “double dent” purchase in the blade to create a clipless modernized expression of the classic penknife.

Spyderco’s non-locking folder history is a fascinating reflection of our identity as a company. To serve the needs of our customers while navigating the shifting sands of international knife laws, we have created, modified, and redefined entire categories of folding knives. In the process, we continually bridged the gap between timeless tradition and reliable high performance.