- Richmond Artifex Gyuto
- Hiromoto Gyuto
- Yamashin Gyuto
- Henckel's Twinmaster Chef
This review consists of :
Knives :
This review consists of : |
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Maker Webpage : Richmond Artifex 210 Gyuto , ad copy :
Richmond Artifex 210mm Gyuto M390. The Richmond Artifex is my fourth knife and this version of the knife is made with M390. BOHLER M390 MICROCLEAN steel is the new super steel on the block. Third generation powder metal technology. Developed for knife blades requiring good corrosion resistance and very high hardness for excellent wear resistance. Chromium, molybdenum, vanadium, and tungsten are added for excellent sharpness and edge retention. Can be polished to an extremely high finish. The Artifex is an all-purpose chef knife/ gyuto that measures 210mm or about 8.25 inches on the blade. The name Artifex is latin for artisan or worker and I designed the knife specifically for people in the food service industry that need a great blade that is tough, versatile and uses world class steel. The knife will take a very keen edge just like the best carbon steels but it has unmatched edge holding abilities. We hardened this steel to HRC 61 for the ideal hardness and toughness.
I designed this knife to be thin with a nice sized handle made of nearly indestructable black linen micarta with a classic 2 rivet design. The handle is designed to give you years of worry free use. Finally, this knife is made right here in the United States with our partner Lamson And Goodnow. The factory edge grind is 50/50 at about 15 degrees on each side. We priced this knife aggressively so line cooks, knife enthusiasts and students could afford it. I hope you enjoy my newest knife. Stay Sharp! Mark Richmond.
From the maker :
A few specifications and comments on this sample :
A few immediate comments :
The issues with fit and finish are a bit problematic for this level of knife, but the over heating of the steel in the grinding is more than a minor concern. That straw color, given the resistance of this steel to oxidization, indicates some serious heat was generated in grinding the profile. This likely has compromised the steel significantly.
The push cutting sharpness was decent on the push but not impressive, not able to match the average performance from Spyderco for example. However there was essentially no slicing aggression. Under magnification the apex was clearly over buffed and rounded. As a point of comparison here are the results on a decently sharp blade (Havalon) :
The Havalon was twice as sharp on a push, more than 50X as sharp on a slice.
On 3/8" hemp :
This is through the heel, closer to the tip the edge is rounded completely and 50+ lbs can not even score the rope, let alone make a cut. In regards to optimal, a well sharpened knife with a very thin edge sharpened at a low angle can make a slice in 4-6 lbs.
In short, the initial sharpness was fairly low and it significantly compromises the cutting ability.
An attempt was made to use it in the kitchen with the as-boxed edge, however given the lack of sharpness it could not make fine cuts on softer vegetables or trim meats effectively. It was therefore sharpened and at the same time the edge was reground to a profile consistent with a chef's knife which isn't a dedicated heavy bone cutter.
Resetting the edge to 10 dps, more inline with a chef's knife which isn't going to see heavy bone cutting, with a 180 SiC waterstone took 1000 pps. The edge was far rougher than expected, a quick check under 50X magnification and the results were obvious. Where the edge had been apexed, large pieces were being knocked out of the edge, likely the carbide aggregates.
In repeated sharpening the same pattern would repeat :
Given the fact the as-factory edge was over heated, this performance could be due to heat/quench damage versus the actual performance of the steel. Given the performance on cardboard trials the former seems likely.
The initial edge retention run on cardboard, results were not impressive. It is similar at best to well hardened 420HC. The knife also had some odd behavior as blunting rate was inconsistent along the edge. The main advantage of PM steels is that they are much more homogeneous in composition. This also leads to a more consistent and even response to hardening.
However the edge on this blade tended to vary consistently in regards to how it blunted which is the opposite of what would be expected. This could be a defect in the steel, or just random influence of cardboard - or it could be due to the initial over heating of the blade by the factory grinding.
An attempt was made to determine the influence of the initial over heating by continuing the cardboard cutting and resharpening. If the performance is being significantly effected by the initial over heating which burnt the steel then the performance should improve with sharpened as damaged steel is being removed.
However, while in repeated trials the performance improved, even after multiple runs and sharpening it never moved significantly beyond a well treated ATS-34 blade 1 . This could simply indicate that the heat damage was fairly extensive.
Now in general more extensive work would be done at this point to try to resolve if the issue was with the steel, how it was hardened or the initial over heating during the factory grinding. However based on the response of the manufacturer to a public complain about his product, there was little desire to continue using this knife. 2 In short, a user had significant problems with a Richmond Chef's knife in AEB-L which was damaged cutting the equivalent of Saran Wrap and mailed Richmond about it. The manufacturer took it upon themselves to make that email public on their form and encourage public bashing of the user.
Nominal composition of m390 / 20CV :
M390 is a PM steel made by Bohler and is strong promoted as a knife steel :
Third generation powder metal technology. Developed for knife blades requiring good corrosion resistance and very high hardness for excellent wear resistance. Chromium, molybdenum, vanadium, and tungsten are added for excellent sharpness and edge retention. Can be polished to an extremely high finish. Hardens and tempers to 60-62 HRC.
However in industry is it referred to a plastic mold steel and there is a significant body of literature on its material properties. For example it has similar impact toughness as S90V, much lower wear resistance but much higher corrosion resistance 2 . This combination of properties is why it is valued as a mold steel. However it isn't so clear why it would be preferred over S90V unless there were issues with corrosion in S90V which is a rare complaint.
As to why these properties have that pattern :
The corrosion and wear resistant martensitic tool steels currently used include grades such as CPM S90V, M390, Elmax, Anval 10V-12, HTM X235, for example. Despite the fact that the overall chromium content of some of these alloys is as high as 20 wt. % (e.g., M390), the corrosion resistance is not necessarily as high as one might expect. Depending on the overall chemical composition and the heat treatment parameters, a large amount of chromium, which is a strong carbide former, is pulled out of the matrix and tied up into chromium-rich carbides. This tied up chromium does not contribute toward the corrosion resistance.
One of the practices that has been used to improve the combination of resistance to corrosion and wear, as exemplified by CPM S90V, is to add vanadium. This alloying addition forms hard'vanadium-rich MC primary carbides and ties up a part of the carbon. Due to the fact that the affinity of vanadium toward carbon is higher than that of chromium, the presence of vanadium in tool steels decreases the amount of chromium-rich primary carbides, all other conditions being equal (i.e., the overall chromium and carbon content, the heat treatment parameters, for example).
S90V has a much higher volume of Vanadium carbides which are much smaller than chromium carbides which is why it can optimize a higher combination of toughness, corrosion resistance and abrasion resistance.
Ergonomics : on the positive :
But :
The handle is well shaped, a few issues such as noted but overall only minor to fix with some sandpaper. Very nice taper at the front and lack of a bolster allows ease of delicate work in forward pinch grips
Security : the is smooth, but no real issues with security outside of heavy fish/gut work due to the extensive shaping and of course the dropped blade.
Durability : the grip is made from Paperstone and thus outside of extreme environments (chemical attacks or hammer level impacts) it is unlikely to suffer any adverse effects. It is generally also much more resistant to abrasion than many of the grips on cheaper knives which are much more of what you would expect from simple plastics.
Overview :
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Most of the pictures in the above are in the PhotoBucket album.
1 : Edge retention slicing cardboard, 15 dps/600 DMT (25 micron)
2 : PM plastic mould steels � wear resistant and corrosion resistant martensitic chromium steels,C. Kerschenbauer, M.O. Speidel
2
: Issue with Richmond AEB-L Chef, T0.1 micron
| Last updated : | |
| Originally written: | 24/04/2013 |