Three Interesting Folding Knife Designs

   03.28.15

We are all pretty familiar with the standard folding knife–a blade, a handle, a pivot, and some way of opening the knife along with a way to lock or hold the knife in the open position. It’s a simple formula, one that has been around at least since Roman times. But like with the cantilever chair (the first two legged chair after thousands of years of three or four legged versions), every once in a while some uber clever person comes up with an entirely new way to do a folding knife. Here are three of my favorite off the wall designs and a little about them.

The Paul Lock

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The Paul Lock is probably the design you are most familiar with and for good reason. Three companies over the last thirty years have tried, and failed, to make this lock work on a production scale. Paul Poehlmann developed the lock in the late 70s or early 80s, and its operation is dead simple. Where the pivot is on a normal knife, there is a button on a Paul Lock. To open and close the knife you depress the button and swing the handle away from the blade. Once the blade hits the lock stop, you release the spring loaded button and the blade is locked open.

To close the knife you do the same, but in reverse. The lock also locks the knife closed.

But as simple as it is to operate, the Paul Lock is daunting to make. Inside the pivot is a series of springs, gears, and mechanisms, all of which have to be very small and have very tight tolerances. Slop in the parts would render the knife inoperable.

Poehlmann originally brought the design to Pete Gerber, back when Gerber was worthy of its Legendary moniker, and Gerber made a few Paul Lock knives. They sold well enough, but because of their complexity, they could not be made with margins sufficient to justify large production. Gerber asked Poehlmann to redesign the mechanism. He did, but it was still too complex for mass production.

Years later, a much smaller outfit (one that grew out of Gerber when it was sold to Fiskars), Lone Wolf, tried their hand at a series of Paul Lock knives. They were more successful and remained in production until Lone Wolf ceased operation when it was bought out by Benchmade. Benchmade also made some Paul Lock knives (that or rebranded old stock), but again they ceased production.

The knife works well and the lock is brilliantly elegant, but it’s not something that can be made on a large scale. If you have a chance, pick one up–they are super fun to fiddle with even if they aren’t the hardest use design.

The Swing Lock

Barry Woods was a custom knife maker from Venice, California. Before that he was a machinist with a knack for inventing solutions to everyday problems. One of the problems that existed at the time he created the first Swing Lock knife was that most folders were very slow to open, even when using both hands. The Swing Lock solved that problem. Unlike most folders of the time there was no backspring putting pressure on the rear tang of the blade; instead the blade swung open freely.

The Swing Lock is pretty clever. First you take your thumb and wedge it into a small divot in the handle scale of the blade. That pops the scale out of a little detent. Then the handle swings around the pivot so that the rear of the handle made a complete circle. As it does, a stop pin or stop bar (depending on the model) “catches” the blade and swings it into the open position. When handle scale is returned to the original position, it again locks into place, but this time the blade is braced against the pin or bar on the handle and it is locked into place.

Even without your hand holding the pieces together, the lock is extremely stable, utilizing the same swinging handle/pin configuration that makes a butterfly knife so strong when locked open (though the Woods design was completely different in appearance and function).

Colt made a run of the Swing Lock knives based on the Woods design. They go for a pretty penny nowadays. Here is one sold on Arizona Custom Knifes:

Image courtesy of Arizona Custom Knives

I was introduced to the Swing Lock at a recent Northeastern Cutlery Collector’s Associate Show. And even though I didn’t buy a single thing at the show, it was 100% worth the trip and price of admission to see the Swing Lock in action.

They are very interesting knives, but very much out of step with current trends. All but a few of the Swing Lock designs were massively thick knives, so thick that they could not be carried in a pocket. Most, like the Colt above, came with a belt sheath. They also lacked pocket clips. And finally, even though some of the more committed Swing Lock devotees can open them one handed, they are still a two handed knife.

All of that said, I don’t know why someone doesn’t made a hard use folder with a Swing Lock nowadays. This is a design that can really take a beating. When the trends change again, maybe we will get a fresh run of Swing Lock blades. Until then, save your pennies because the collectors have driven up prices into the stratosphere. I tried to by a Swing Lock. The cheapest one was $300, and it had an edge like a car bumper.

Linkage Knife

A linkage is a mechanism designed to manage movement and force across a space. Those old wooden stair gates are linkages. That idea of using linkages to cover a space was incorporated into a knife by the European designer Scorpio Designs. The resulting knife is truly jaw dropping–like nothing else in the world. While the Paul Lock and the Swing Lock look like regular knives and function differently, the Scorpio Designs “Linkage Knife” (for lack of a better term) both looks and functions 100% differently. I could try to explain it, but its just easier to see it in action (sorry for the poor video quality, there aren’t a whole lot of these knives out there):

The Shapeshifter EDC is unquestionably one of the coolest things I have ever seen.

There are a few ripoff versions made by Kevin Johns-type companies, but so far as I know no legitimate production company has tried to make these. In the end, their viability as a production scale product is almost certainly doomed by the fact that they are just really strange. Nonetheless the GIF on Scorpio Design’s product page is hypnotic.

Knives are so cherished a tool, it’s not surprising that even fifty millennia after the first sharp edge was made and used as a tool, we are still finding new ways to make knives. I hope these three designs were interesting. I know I loved discovering them the first time I came across them.

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