This review consists of :
Some promotional copy on the back :
A few more details :
A few finish issues :
Some numbers :
On 3/8" hemp :
These are very low, the 3/8" hemp numbers are about 7 times as high as they should be given the very thin stock of this blade and the very low edge angle.
Most importantly for the kitchen stock work it will not cut a tomato as-boxed so the #weeks in use before sharpening is the lowest yet, 0 .
The ergonomics were such a significant issue that before any significant work was done in the kitchen the knife was modified as noted in the picture on the right :
As a utility knife it was problematic for two reasons :
The combination of the two of these means that the stiffness is very low (due to the stock thickness) which also reduces the strength as does the softness of the steel. Even on something as simple as trying to slice up an onion the blade flexes significantly which makes such work awkward.
While it might not sound like a lot of a difference, the stiffness is cubic with thickness and thus this knife is almost 1/10 the stiffness of a knife which is just 1/16" thick and this is a drastic difference as it means it bends similar when 1 lbs of force is applied as does a 1/16" blade which is used with 10 lbs of force applied.
On harder vegetables the issue with the lack of stiffness and strength is even more pronounced. On something as simple as a few carrots the flexing of the blade is that severe that :
Both of these are also made worse by the fact that even though the blade is very thin as it lacks a primary grind the edge is fairly thick (the full stock thickness). It is in fact comparable to the thickness of an edge on a large chopping blade and this raises the resistance significantly compared to a thicker blade with an actual primary grind.
Ergonomics : the main issue with the ergonomics is that the usable grip length is only 6.5 cm which means it is a three finger grip for anything but small to moderate hands.
More importantly, for any paring or utility work which is gripped forward, especially in a pinch, the index finger will run across the extended choil which is very thin and ends in a squarish point. The end of the handle is also fairly sharp in the hook. These issues were so severe that the handle had to be modified as noted in the above before it was extensively used outside of the stock edge retention and sharpening work.
Security : the issues with security relate to the same problems as the ergonomics in that it is difficult to get a working grip due to the size of the handle.
Sharpening the knife is nontrivial because a burr formed can not be removed by grinding the TiN side without of course removing the TiN from the edge. In fact even just destressing the edge is not trivial :
Sharpening is similar :
The problem is that the TiN is essentially a ceramic and thus any coarse grit which hits it will cause it to fracture. The optimal method after some experimenting is similar to :
Again if the TiN is hit with any stone but the finishing grit it will be very difficult to remove the scratches from it and it basically has to be destressed and the process started over. The ideal way to sharpen it then would be a water cooled rapid grinding with a fine/finishing abrasive.
As the only knife used in the kitchen, it was brought into rotation on March 16, 2013 and lasted zero weeks before it had to be sharpened as it initially could not cut a tomato so it failed to be able to be used at all.
In standard Cardboard trials it behaved on the low end of Class I steels. This was fairly interesting because it didn't seem to be influenced at all by the fact it was TiN coated.
| # runs | Sharpness | 15% | 10% | 5% |
|---|---|---|---|---|
| cardboard cut (m) | ||||
| 2 | 35+10(11) | 0.7+0.0(0.2) | 2.8-1.0(0.6) | 21- 8( 5) |
The reason that the TiN coating does not seem to make a difference is that as the steel wears behind the coating, or to be specific on the other side of it, the coating itself (which wears so much slower), can not take the forces on the edge by itself and large pieces of the edge just break away.
The problem here was seen by Buck on the IonFusion line where they noted that while the blades would score very well on CATRA tests, the feedback by the users did not report the extreme gains seen in the CATRA tests. It was quickly determined that the difference was because the thin TiN strip of metal along the edge would crack off in use by people but the machine doing the CATRA cutting could hold the blade so stable that that small piece of TiN would not break off.
The main lesson there is make sure in any experiment that what is being measured is actually representative of what needs to be measured. Precision without accuracy is useless.
A quick soak test to check large differences among steels, the knife was :
As expected the knife was not significantly effected by the exposure to the salt water and simply rinsing off the blade and wiping it with a paper towel removed the salt and left no sign of corrosion.
These very inexpensive knives are usually made from steels of the class :
These are very tough and extremely corrosion resistant. The downside is that they are limited in hardness to less than 55 HRC.
In addition the tip was properly formed and the blade was narrowed to improve coring and other precision work.
Overview :
Comments can be emailed to Intro
and/or the YouTube Playlist for Kitchen Knives.
Most of the pictures in the above are in the PhotoBucket album.
| Last updated : | |
| Originally written: | 18/08/2013 |