This review consists of :
A few specifications :
The Shikra is quick, agile and mean. Everything a neck knife ought to be. From peeling apples to taking care of any business that may confront you, the Shikra delivers.
The initial sharpness was very specialized, a few notes :
Checking the edge straight on at 50X magnification the edge is formed by the tungsten carbide which is what would be wanted.
Checking the edge with a few sharpness tests :
The sharpness is low to medium on any similar test, it is just extremely coarse. Checking it on 3/8" hemp :
Comparing the rough carving ability to a #1260 Mora on some pine (0.5x1.5") making two inch points the cutting ability of the Shikra was clearly able to cut alongside the Mora. The Mora would takes 4-5 slices to make a point on the pine and the Shikra jus 5-6 slices. The strong points are :
There are a few problems though :
With the initial edge, a few materials were sliced up to get a feel for the
cutting performance of the Shikra :
A few things were immediately obvious :
In some more detail on some heavy cardboard which is fairly difficult to cut
because it is :
The Shikra takes about 9-10 lbs to make a cut. In comparison a full flat ground blade of 1/16" stock with a thin and acute edge will make the same cut with 2-3 lbs.
The difference is only a few pounds and while it is easily felt
it isn't like it the rate of fatigue is so high that it makes
a difference as beaking down the box only takes
a half a dozen cuts. However
there are a few significant effects which
tend to get more and more pronounced as the cardboard gets thicker :
A little work with a purpose, some fire starters :
Some harder work :
Summary :
Overall, it pretty much behaves like other 6AL4V titanium blades. The edge isn't enforced in any manner durability wise as an uncarbidized blade.
To the right is a video by NeptuneKnives who is a dealer for Warren Thomas. He uses the Shikra in a number of utility applications on woods compared to a large number of othe knives for :
Now it is obvious that the Shikara was not designed as a kitchen knife, however it is promoted semi-aggressively as a self defense knife and the reality of that work is the cutting of flesh, possibly not a pleasant topic of discussion for some, but relevant to this knife.
Now it is just as obvious that practical demonstration isn't possible or reasonable and thus a simulation is necessary. In this case the Shikra was used on a few small game animals including :
Again there are knives designed just for this work, but there is some
curiosity in regards to the carbidized edge, the chisel grind and the general
utility of such a basic handle/grip.
There are a few immediate observations when using a knife like the Shikra for such work, the first is that yes it can be done, the second is that it really isn't a sensible idea in regards to efficiency, and really is mainly either something which is either as a source of amusement or experimentation.
There are many limitations which start to be apparent very readily in using the Shikra for such work :
If it is compared to a knife which does this kind of work even at a passable level like a standard Henckles Twinmaster, well the Shikra looks and feels clumsy at best. But if it is nice and sharp in the beginning, and only a small amount of work is done, well the practical performance difference isn't that extreme.
Now does the carbidized edge make any difference? Not in this small amount of work as a couple of game birds and a rabbit is not enough work done to even blunt the edge on the titanium alone and thus if the knife starts out shaving then it ends shaving as long as no heavy bone cuts are made. The carbidized edge doesn't make any difference in regards to making the edge stronger as the Titanium will slightly dent on the heavier bone cuts, similar to, and possibly even more than a very inexpensive stainless steel knife in 3Cr13.
What about the chisel grind? Well, before there are any complaints about suitability of work using the knife for simple peeling, the promotion of the knife is clear :
The Shikra is quick, agile and mean. Everything a neck knife ought to be. From peeling apples to taking care of any business that may confront you, the Shikra delivers.
Substitute some potato for apple and there are again a few obvious conclusions.
The knife has to be elevated to a fairly high angle, twice that of a v-ground blade and that makes the peeling fairly awkward unless waste is not an issue as thin peels are most easily generated with the knife ran/cutting very flat to the vegetables. Now again, for a small amount of work, no real issue, but the difference is likely to be significant when working on a pot of mashed for a large family.
In general as a utility knife, it works but there are a few obvious drawbacks compared to a kitchen utility knife :
The chisel grind isn't of course in general a negative for a kitchen knife, there are lots of very high performance kitchen knives which use chisel grinds, common in Japanese knives for example which tend to be used for particular vegetable cutting, or slicing fish. The problem here is that the thick grind increases the force and this increased force combined with the chisel grind tends to make the knife skew.
On softer fruits and vegetables it is sort of ok, again these are easy to cut and it is mainly a matter of comfort vs raw functionality. But moving to stiffer vegetables :
As the force keeps rising as the vegetables get stiffer, the knife starts to skew more radically. Now this can be off set by twisting the knife in hand at the start of the cut, but it quickly becomes an exercise in exercising vs practical efficiency. It is ok dicing up some small relatively soft white potato, but on turnips, it simply isn't practical. Can it be done - sure but trying to keep the blade cutting straight, dealing with splits vs cuts and working with several times as much force it really is something which isn't practical The only real point to be made is that since it is a neck knife, it can be easily worn and carried in many situations and this it can be used for simple food preparation and is many times better than for example using a very dull kitchen knife at a friends/family members.
Where the Shikra does stand out in kitchen work is doing the tasks which are not that favored by kitchen knives, the common utility tasks :
A lot of this work is done by utility style scissors, which can be useful for the heavier cutting s the very thin grinds and distal tapers on the kitchen knives can be damaged, plus the very high sharpness can be lost. However as the Shikra is designed, due to the carbidized tungsten carbide to hold a rougher slicing edge, it excels doing that type of work.
Now in general, for people sharpening their own knives, cutting that kind
of material isn't extremely prone to blunting, but it is a lot more so than
just cutting foods and so most people will avoid it to avoid sharpening. A
knife like the Shikra, being carried and used as a utility knife can have its
use in the kitchen in that respect.
In general, looking at not specific cutting but more utility, the durability of the Skikra which comes from the :
allows it to work well as a general utility tool. Now the point is thin, so some care has to be taken to avoid over loading it, but the high ductility means it will likely just take a set/bend even in such cases. Given the tough/durable nature of it, and again how it is designed for rougher cutting due to the carbidized edge, it works well for harder (ab)use such as punching out the side holes in ant tins and similar contacts. This isn't something which is sensible with something like the Spyderco Air, but is easily done with the Shikra.
Nominal composition of 6Al4V :
This particular alloy of Titanium is heat treatable and can be hardened to form martensite producing a very high specific strength (strength to weight ratio) and high impact toughness 1 .
In regards to edge retention, titanium strongly resists fracture and corrosion and so the edge retention isn't reduced due to corrosion or micro-chipping as can commonly be found in steels. However it is fairly soft and much weaker than steels and the Tungsten Carbide does not reinforce the edge significantly in regards to denting and deformation. It takes similar dents/deformation in harder cutting as a typical uncoated Titanium blade.
However the carbidizing of the Tungsten to the Titanium does give it one interesting property. The Tungsten Carbide is much harder than the Titanium, it is even much harder than any steel and it is very wear resistant. This difference is so great that the Titanium actually wears away from the edge much faster than the Tungsten carbide which leaves the apex in a state of being the thickness of the carbide layer.
This means in use, while the initial blunting takes place similar to steels, once the Titanium has worn away and that carbide layer is exposed and become the apex, it essentially will stay that way for practically forever as even though the tungsten carbide will wear, the titanium wears faster and thus the apex always stays the same thickness. This is essential the same process by which animals have teeth which are self sharpening :
Rodent incisors have enamel on on the anterior surface, causing differential wear and continuous sharpening of the incisors
and is also exploited in very harsh tooling such as excavator teeth 2. However there are limitations of this type of application which are known in industry :
However, knives with this type of coating have a number of disadvantages that limit their applications. The coating process does not allow a thin coating to be produced - the coating thickness is typically 25-30 microns. The coating consists of randomly distributed hard particles in a substantially softer metal matrix, and this coating structure does not therefore serve to form a straight self- sharpening edge within the thickness of the coating layer. This sets a limitation on the sharpness that can be achieved with a blade having such a thick hard coating layer. Furthermore, the cutting edge formed by discrete particles of hard material projecting from a matrix does not provide a smooth cutting action, but instead acts by tensile tearing of the material being cut. This typically requires a higher force to be applied to the cutting edge as compared to a purely compressive cutting action of a scalpel, for example.
Further the same patent shows with a different type of coating much different performance can be achieved to produce an initial sharpness which is similar to a standard steel blade and which is strongly self-sharpening at a much higher sharpness. Note there are many ways to do this including ways to transform the entire edge to an extremely dense concentration of vanadium carbide which can give very strong performance :
Standard blade : CATRA : 750 TCC Vanadium Caride Diffused : CATRA 34, 400 TCC
It would be interesting to see some of these techniques moved more into knives vs tungsten carbidization which as noted has severe limitations due to low initial sharpness and edge retention at a very low sharpness.
In regards to sharpening, this is definitely one of the aspects of this knife which is likely to be troublesome to most because of one central problem the knife can not be deburred on the carbided side and using burr based sharpening is extremely common and this tends to burr really easy due to the very high ductility of the material and how it tends to be abraded by ploughing which deforms the material.
Ideally the apex is just reached and not formed to a burr, however that isn't nearly as easy as it is with steels because again the grinding can only be done on one side so a lot of the techniques used with steels to minimize a burr can't be done (alternate passes, cross scratch patterns, etc.). This difficulty in fact is so high that it has lead some to conclude it can be be sharpened to a high sharpness at all. However it can be done, it just requires a different technique.
With standard water stones, the following was used :
The exact grits to use depend on the desired edge finish but the main point is that once the edge is apexed it needs to be lightly cut into the stone to remove any burr that is formed and remove the coarse scratches at the very edge as there is no ability to polish them off from the other side. Using this method it is possible to achieve a sharpness of 70-90 grams on the Esprit thread which easily easily shaves, slices newsprint readily and can push cut at a small angle off of a true 90.
However with some more experimenting, a much more optimal technique was used which was to use a fairly muddy stone or combination of them which inherently minimize burr formation due to the fact the mud will plough into the apex and grind off burrs. These stones can be problematic to set the final apex so that is done with a harder and slurry free stone. The current method is similar to :
If a higher polish is needed for extended push cutting, then it can be achieved by adding in a Naniwa Aotoshi 2000 and finishing with a MXF DMT or similar. However the carbidized edge really isn't design to hold that kind of high push cutting sharpness so it defeats the purpose of the carbidizing.
Keeping in mind the handle is a slab with no scales :
Comments can be emailed to A little use
Or in the YT playlist.
Most of the pictures in the above are in the Shikra album at PhotoBucket.
1 : Blade materials, reference page
2
: Sabre Teeth - Self-Sharpening Excavator Teeth
| Last updated : | 11:29:2015 |
| Originally written: | 11:29:2011 |