Article

Blade Locks and Assisted Openers

by Dexter Ewing - Field Editor for Blade Magazine

First, we discussed the different steels that are available to make blades from. Then we took a closer look at the wide variety of handle materials. And finally, we have arrived at the last installment of the Blades By Brown knife tutorial – and we’re getting’ mechanical this time – with folder blade locks and assisted opening mechanisms. Of all three, these topics presented here are perhaps my most favorite when it comes to folding knives. Why? Because they are, like I said, mechanical in nature and I am a mechanically inclined type of guy. Not to mention, I tend to favor folders. A lot!

There are basically two types of folder blade locks. They can be found on the majority of custom and production knives currently on the market. First up, we have the lockback. This consists of a stainless steel lockbar that runs nearly the entire length of the folder handle. At the rear of the handle is a cut-out in which part of this lockbar is exposed for the purpose of placing one’s thumb on in order to apply slight downward pressure to raise the front end of this bar [which by the way works off of a pivot situated somewhere in the middle of the handle]. At the front of this lock bar is a tooth that will fall into place on a corresponding gap on the tang of the knife blade. The lockbar has a leaf spring of some sort inside the handle that pushes up on the end of the lockbar, therefore putting constant pressure on the tooth end of the lockbar itself. When the blade rotates out and into the fully open position, this lockback will follow the contour of the tang until it drops into the corresponding gap. At this juncture, the knife blade is fully opened and in the locked position, ready for use. This style of lock is very popular among commercially manufactured knives. They usually are the large folding hunter style knives such as the venerable Buck 110 Folding Hunter, Buck 112 Folding Ranger, Boker Optima exchange blade folding hunter, and the Cold Steel Trail Guide folder. Some tacticals are equipped with a lockback mechanism like the Cold Steel Voyager and the Spyderco C95 Manix.

The second common and popular blade lock is the liner lock®. The liner lock is executed by cutting an “L” shaped slot in the metal liner of a folding knife, and bending the cut portion laterally so it will stick up and out a bit. Thus, when the knife is assembled, this bend in the liner will exert tension on the side of the blade tang as the blade rotates outward to the fully open position. When the blade reaches its fully deployed position, this spring lock bar will then move laterally, effectively wedging itself on the ramp of the blade tang. Thus, a secure and rock solid lock up is so achieved. To unlock the blade, simply grasp the opened knife with one hand in such a way that one’s thumb rests on the lock spring. With the thumb, apply lateral pressure, pressing the spring towards the closest handle scale and with the index finger of the same hand, rotate the blade closed a little. Mind you at this point, your thumb is traversing the arc of blade travel as it is folded back into the handle. You will want to remove your thumb from this zone in order to avoid accidental cuts [believe me, those that are new to liner locks are prone to this!] Once your thumb is safely out of the way, continue to rotate the blade closed with the index finger. The liner lock is more advanced than the aforementioned lockback. Why? The liner lock permits one to safely and effortlessly open and close a folding knife blade with just one hand. Imagine working on a ladder and grasping something in one hand. With the other hand, you can retrieve your folder that is clipped to the pocket, open it, cut the material you are holding with the other hand, close the knife, and clip it back to your pocket without having to use two hands to bring the knife blade into play. Conversely, the liner lock® is more difficult to manufacture because in order to get a properly made liner lock® to function properly and safely as it was thus designed to, there is an interesting mix of physics and science involved. For instance, the point of contact on the blade tang must be ground at the proper angle in order to apply enough friction to hold the blade open without the lock failing by simply applying pressure to the tip of the blade on the spine, or if the blade spine were to be dealt a sharp impact. An improperly made liner lock® will fold faster than a poorly maintained restaurant watching the health department inspector walking towards their front door! Yes, liner locks® maybe finicky but a properly executed liner lock® will most certainly hold rock solid. And here’s another tip. By virtue of nature and through time, liner locks will wear in a bit. Meaning, the lock bar will travel further over to lock up the blade. And that’s fine. What you need to look for when buying a new liner lock knife is the lock bar hitting at the lower 1/3 portion of the blade tang. As it wears in, it will travel a little more towards the center of the tang. If a new knife, straight out of the box, hits at the halfway point, in my opinion that is already too far when you consider the “wear factor”. A lot of the popular tactical folders on the production market today have liner locks such as the Emerson Commander, Spyderco C36 Military model, the Al Mar SERE 2000, and the Columbia River M21.

There is a variation of the liner lock® that is known as an integral lock. The integral lock takes the concept of the liner lock® a few steps further, which in turn yields a bull-strong lock and lockup. As opposed to being cut and bent from a metal liner that is about 1/16 of an inch thick, an integral lock is cut and bent from a much thicker piece of metal…usually the material of choice is titanium as with liner locks. Hence the name – the lock is integral to the handle. Instead of a lock contact surface measuring 1/16” wide, you get a surface that is two, three, or sometimes four times the thickness. Hence, a much improved lockup quality. Almost as close to being a fixed blade as a folding knife will ever get! Some popular production integral locks are the Chris Reeve Knives Sebenza, Benchmade Knife Company 630 Skirmish, and the Strider Knives SnG. Integral lock folders are generally thinner than the traditional dual liner build of tactical folders, because you are not adding any material.

You think that by now I’ve covered it all when it comes to folder blade locks. Right? Wrong! In my opinion, this is where the fun stuff starts. There have been some knife companies out there who have explored new and different blade locks, thus proving that the spirit of innovation is alive and well in the knife industry. Benchmade Knife Company has their innovative Axis Lock mechanism.

Axis Lock mechanism by Benchmade

This “new generation” blade lock has been out on the market since 1999 and has furthered Benchmade’s reputation as being an innovative knife manufacturer. The Axis Lock is the design of the father and stepson knifemaking team of Bill McHenry and Jason Williams. These two gentleman hail from rural Rhode Island and they have developed a following in the custom knife industry as building some of the most exquisite automatic folding knives one will find anywhere. The Axis Lock may seem complicated but in reality it isn’t. Basically, the Axis Lock involves a cylindrical steel lock bar that maintains constant contact under spring pressure with the blade tang. When the blade rotates out to the full open position, the Axis Lock bar springs forward into place on the corresponding flat portion of the blade tang. Thus, the blade is wedged in between the blade stop and the Axis Lock bar, thereby securing the blade open. By pulling back manually on one of the protruding lock releases on either side of the handle, the Axis Lock can easily be disengaged and the blade rotated back to the closed position. The Axis Lock is very durable, and the Omega shaped springs that drive the lock bar are shaped in such a way as to provide life long service without fail.

SOG Specialty Knives is another manufacturer that has a folder with one of these new generation blade locks. Dubbed the Arc Lock, SOG’s lock works very similar in concept with the Benchmade Axis Lock, with the exception of the fact that the Arc Lock’s lock bar travels in a radial pattern, hence the moniker. SOG’s enormous Pentagon Elite II folder is definitely a hand full with its blade measuring 5 inches in length and an overall length of 10 ¾ inches! The blade is secured via the Arc Lock, and its inception was perfect for their folding knife of this size. Like the Benchmade Axis Lock, the SOG Arc Lock permits easy one hand opening and closing. The lock can be easily and ambidextrously released, making this a mega folder to satisfy both right-handers and southpaws!

Not to be left behind, the crew at Spyderco also has devised a locking mechanism of their own design. Dubbed the Compression Lock, this lock is the only one on the market that is sort of a hybrid. The lock release is situated on the handle spine like a lockback, but it operates similar to a liner lock. Think along the lines of an upside down liner lock, that is the best way I can describe it in words but it doesn’t quite function as a traditional liner lock® would. Basically, the Compression Lock relies on the lock bar wedging itself between the blade tang and the blade’s stop pin. Hence, the name…sort of compressing itself in between the blade tang and stop pin.

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Now, here comes the fun part! And I’m talking about assisted opening mechanisms…the things that jump to the delight of many a knife enthusiast. These hybrid folding knives are the perfect blend of an automatic knife and a manual knife. Assists have the jump of an auto, but in a much more legal-friendly manual opening folder. Meaning, the blade’s outward motion is initiated by the thumb or index finger and then the assist mechanism kicks in to drive the blade fully out and to the locked position. The company who is the pioneer in the assisted opening genre is Kershaw Knives. They have custom knifemaker Ken Onion on board to lend a very fresh, hip, and stylish folders featuring Onion’s own Speed Safe mechanism. Take a look at the entire Kershaw Ken Onion line and what you’ll see is a complete line of assisted opening folders that have that panache that savvy knife buyers are craving. The latest from this dynamic duo is the 1585BR Baby Boa.

Kershaw -Baby Boa

Essentially a scaled down version of their larger 1580 Boa folder – reduced to the size of the company’s wildly popular 1600 Chive. Camillus has entered the assisted opening arena in a big way. And it is a very big way, in the form of the Aftermath, a 5 ½ inch blade length mega folder designed by Darrel Ralph. This big blade is driven by Camillus’ own Robo Power Assist mechanism. Consisting of a heat treated stainless steel leaf spring, the Robo Power mechanism works by pushing up on a strategically placed peg on the blade tang [hidden within the pivot area]. The Robo Power Assist is beefier than the Speed Safe’s wire like construction. One advantage over the Speed Safe that it has is during the opening sequence, the user is able to determine when the blade will exactly “take off”. SOG Specialty Knives offers their Flash series of folders with the company’s own SAT mechanism. SAT stands for SOG Assisted Technology. The SAT is kind of like a piston and cam type action. A firm push up on the thumbstud of the Flash will send the blade rocketing out of the handle.

The SAT is also designed in such a way that it holds the blade closed securely, and along with the incorporated safety, insures against accidental blade deployment. Not to be left behind by the assisted opener movement, the folks at Benchmade Knife Company have produced their first assisted opening folder in the form of their Warren Osborne and Mel Pardue designed model 670 Apparition, shod with Benchmade’s own Optimizer technology. The Apparition is a slightly different breed of assisted opening folder in the sense that the user can manually de-activate the assisted opener, rendering the model 670 as a standard, manual opening liner lock® folder. Simply by loosening a small hex screw located in the butt of the handle, the steel spring rod slides out of the handle. If assisted opening is desired, the steel rod can be inserted back into the handle and then the blade will rocket out of the handle with speed and authority with little effort. And so, regardless of which brand of assisted opening folding knife you are looking at, what you are getting is a that is legally as close to a full automatic knife as most knife enthusiasts will ever get to own. Assisted opening knives also provide one who might have limited use of the hands a quick opening folder with minimal hand manipulation. So, they are neat and practical at the same time. They are also the current trend in tactical folding knives today, as illustrated here.

And with that, this concludes the third and final installment of the Blades By Brown Knife Tutorial. We sincerely hope you found this information to be useful, and that you use these articles as reference sources for your building your knife knowledge. Every year brings a new round of new and exciting knives, materials, and technology. With the way things have been going over the years, there is no shortage of new ideas and designs. My friends, the spirit of innovation is alive and well in the knife industry! Now’s the time to take the plunge; take advantage of these new materials and new mechanisms that are now readily available to the knife consumer.

**The opinions expressed by Dexter Ewing do not reflect those of the staff of Blades By Brown Cutlery**

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