The Zero Tolerance 0454 is from the company’s limited edition series. It is yet another Blade Show, Over All Knife of The Year award winner (2013) adding to KAI’s impressive list of such knives that include the O777 (2011) and the 0888 (2012). Their LE 0600 designed by RJ Martin was also the recipient of the Blade, Collaboration Of The Year in 2012. This design is a collaboration with Dmitry Sinkevich (Дмитрий Синкевич), a Belarusian knife maker who is known for his custom work as well as his designs for Fantoni’s CUT series and Shirigorov (Широгоров). He also designed the Nura under the Kershaw brand.
I’ve personally been trying to get a hold of this for a while. The design is striking, functional and much like the 0777 smartly leverages the materials used. Having handled the majority of ZT LE’s, I can say that this is possibly the most refined of the lot. It includes many high end features without feeling gimmicky or confused.
The blade is made from 3 separate interlocking braze welded components. This composite uses Sandvik 14C28N for the core (including the tang) and CPM D2 at the spine and cutting edge. 14C28N is a stainless, knife designated steel that includes Nitrogen in its alloy for added corrosion resistance. CPM D2 is an upgraded version of the popular AISI D2 tool steel. Using a powder metallurgy process, Crucible is able to achieve a more homogeneous mixture of elements resulting in an even distribution of carbides. The result adds up to improved mechanical properties.
To construct the blade each part is cut within close tolerances and fit with a copper brazing paste between the joints. It is then heated up to 2030º where the copper liquifies, filling the joint using a capillary action. The process is done in a vacuum negating the need for flux and leaving an extremely clean, integral seam. Heat treating and tempering follows, yielding a hardness of around 59-60 Hrc for the D2 and a lower hardness for the Sandvik core.
|CPM D2||1.55||11.5||0.80||.9 to .95||0.40||N/A||0.40||0.03||0.03|
|14C28N||0.62||14.00||N/A||N/A||0.60||0.11||N/A||0.025 max||0.03 max|
While KAI’s blade specific manufacturing process is patented, using a harder edge steel and softer core isn’t a new idea. In fact many ancient blades benefited from a similar configuration. A softer, more ductile core is tough and when coupled with the superior edge of a harder more brittle one, the final blade benefits from the properties of both. This technique was heavily used in Ancient Japanese swords and high end domestic cutlery. It is still used by both traditional smiths and automated manufacture. The KAI variety also appears in some of Kershaw’s mid-range knives like the Rake, Leek and Junkyard Dog . If you are interested in learning more about the process you can read the patent and a little on vacuum brazing.
Even though the advantages of a clad or laminate blade are well documented, I’m not totally sure of the strength of KAI’s composite blade weld in this case. Since the pieces are butt jointed, there isn’t any added mechanical component helping to fasten each part, like a dovetail or undercut. The bond is reliant fully on the copper brazing material’s integrity. Regardless, in my opinion the aesthetic advantages in a Limited Edition knife like this makes the choices appropriate. It is likely strong enough for normal use anyway. This is probably even more true in that the majority of owners will have this knife strictly as a collector’s item. After all, the scarcity and price of such knives will make them difficult to put to use for most people. It would also depreciate the resale value.
On the finished blade the D2 is etched with a satin finish for the Sandvik. The difference in surface treatment and copper weld color makes for a bold contrast that really sets off the angular pattern. KAI’s composite symbol and ZT logo are laser etched on one side of the blade with the knife info and unique serial number on the other.
The profile is a long, sleek modified drop point. It has been given a flat grind that is met with a wide swedge. The edge is finished with a keen secondary bevel that unsurprisingly ships razor sharp. If you were to use this blade frequently there’s a deep choil for sharpening. At the handle the spine has a row of jimping that’s cut through the PVD revealing the natural color of the D2. Another great facet of the design.
The blade’s sole deployment method is a flipper. A very strong detent results in an extremely fast and reliable opening each time. The authoritative action is helped along by two thrust bearings that contact each side of the blade and handle. These sit in races and on the handle side, against steel washers to buffer them from the carbon fiber.
KAI calls their bearing pivot KVT or “Kershaw Velocity Technology”. While the name is a trademark, the use of caged bearings is not proprietary, found in many industries and applications as well as other knives like the CRKT Hi-Jinx. The popularization of bearings in knife design could probably be attributed to the Ikoma Korth Bearing System, best know as IKBS. Bearings are advantageous because they have a wide load bearing base to inhibit lateral play but minimal surface contact. Because the ball bearings housed in the cage rotate freely, they also improve motion since parts roll better than they do slide. Custom hardware with a radial pattern finishes off the pivot adding to the sum of the attention to detail.
On opening the blade is held firmly and without play by a sub frame lock. On the end of the spring arm there’s a hardened stainless steel insert. The use of stainless instead of titanium improves the interface since it is similar to the tang hardness, therefor wearing more evenly. It also prevents the stickiness often associated with titanium to steel locks. The “sub” part of the name generally means that part of the locking leaf is concealed beneath the scale while the exposed part is flush with it. A sub frame lock can be part of a full liner or be partial. In the case of the 0454 it’s the latter, with the concealed portion recessed into a slot milled in the carbon fiber. The whole manifold is fastened by bolts that enter from the outside of the scale pulling it against the inner wall. In order to protect the spring integrity there’s a hidden over-travel stop built into the steel insert. This works by undercutting the handle where it butts up against a slot milled into the underside of the scale.
As with the blade, the handle of the 0454 is an impressive combination of materials and machining. The main body is made from carbon fiber and is liner-less, saving considerable weight. The exclusion of liners on this knife is an excellent choice since the high strength-to-weight ratio of reinforced polymers like Carbon Fiber are extremely durable making them appropriate as a structural handle material.
Each half of the knife is separated by a detailed titanium back-spacer. Starting around mid-handle, the component has chamfered edges that appear to pull away from the inner sides of the scales. It then widens into two rows of jimping that wrap around the pommel. The texture is slightly raised for added grip and is especially effective in a reverse grip, sitting where your thumb lands.
The ergonomics on the knife meet the fit and finish with equal worth. The inner edge of the grip is contoured with finger grooves to hold you hand in place. On each end, the handle flares to prevent slipping in either direction. At the front this is achieved by the flipper that also acts as a finger guard. Toward the back a slight flare in the pommel serves to maintain your grip if draw cutting or pulling the blade out of something. In a standard grip the jimping on the blade’s spine does a great job of helping with controlled cuts and provides some tactile feedback. All the surfaces have radius cut edges for comfort and the faces of the scales are contoured. This profiling is what ZT calls “3D machining.” While all CNC milling operations are 3D, the marketing term means that extra machine time is given to these knives. The added investment ensures a more finished, comfortable and attractive handle. It’s also is a separation from slab built handles like those found on the company’s more affordable options.
For carry there is a machined titanium pocket clip. Clips that are milled rather than stamped and bent are quite often a sign of a quality knife. It goes without saying in this case of course. The retention is a bit tight for my taste but if you do carry around a knife this rare and expensive you’ll be happy to know it isn’t going to come out of your pocket accidentally. It also looks great, tying in with the rest of the handle and balancing out the visual weight of the back-spacer and lock. The over-all profile is very similar to clips found on Shirogorov knives. There’s also a lanyard hole.
The ZT 0454 is another knife in the Zero Tolerance line up that takes full advantage of the processes possible in contemporary knife manufacturing. Each component is finished beautifully, rendering justice to Dmitry Sinkevich’s outstanding design. Like the ZT 0777 it also harnesses the physical properties of the materials used, especially the Carbon Fiber and Titanium producing an outstanding weight to strength ratio. The addition of the two toned composite blade is also a welcome touch and a visual upgrade from a single piece blade. While these knives are hard to come by, I would highly recommend it to anyone who has access or those willing to pay the aftermarket premium. Fans of Sinkevich will also appreciate the 0454 as it is an exceptional production example of his work.
For more on Sinkevich design visit http://sinkevichdesign.ru/en/
Overall Length 9.3″ (23.6 cm)
Weight: 4.1 oz. (116 g)
Blade: 4.1 in. (10.4 cm)
Steel: CPM D2/14C28N
5.2 in. (13.2 cm)
Machined carbon fiber
Sub-frame lock, with hardened steel lock-bar insert
Right hand titanium pocket clip
Made in the USA
Video correction : The D2 on the blade is etched, not PVD coated.