# Sukenari knives



## Alexec (Jan 13, 2018)

Sukenari knives!
What do you think?
Im considering r2/sg2 , zdp189 and yxr7 series.
Please comment!


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## Paraffin (Jan 13, 2018)

I have a Sukenari 165mm petty knife in HAP40 steel with an ebony handle. Fit and finish is first class, and the HAP40 edge retention is excellent. I don't know what the larger knives are like, but if they're similar to this petty, then I'd call it a "medium weight" grind. 

The HAP40 steel isn't quite as easy to sharpen as my carbon steel knives, but I can get it plenty sharp enough for what I use it for; mainly soft protein slicing. 

One note about HAP40 if you go for that, is that it's a "semi stainless" steel. It doesn't rust or need as much care as a carbon steel knife. I can treat it the same as my stainless steel knives. But the exposed edge below the cladding will show a very slight patina, just a slightly different shade of silver below the stainless cladding. I think it looks neat. The ZDP189 and R2 knives are full stainless and won't show this very slight patina effect.


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## Barmoley (Jan 13, 2018)

I have a 240 yxr7. It is actually 235x50 or so. The grind is medium weight. Food separation is good. The core steel discolors on onions quickly, slower than 52100, but definitely not stainless. It seems to do better with tomatoes and similar produce. It is semi stainless, but more reactive on onions than SS in SS itinomonn or SS gengetsu. I havent sharpened it yet, so cant comment on that. Fit and finish is good, but choil and spine are not rounded, even though they are not sharp. I like the profile and the balance with ebony handle from K&S is good.


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## Alexec (Jan 13, 2018)

Paraffin said:


> I have a Sukenari 165mm petty knife in HAP40 steel with an ebony handle. Fit and finish is first class, and the HAP40 edge retention is excellent. I don't know what the larger knives are like, but if they're similar to this petty, then I'd call it a "medium weight" grind.
> 
> The HAP40 steel isn't quite as easy to sharpen as my carbon steel knives, but I can get it plenty sharp enough for what I use it for; mainly soft protein slicing.
> 
> One note about HAP40 if you go for that, is that it's a "semi stainless" steel. It doesn't rust or need as much care as a carbon steel knife. I can treat it the same as my stainless steel knives. But the exposed edge below the cladding will show a very slight patina, just a slightly different shade of silver below the stainless cladding. I think it looks neat. The ZDP189 and R2 knives are full stainless and won't show this very slight patina effect.



Would you buy it again? I mean you are satisfied right?


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## Paraffin (Jan 13, 2018)

Alexec said:


> Would you buy it again? I mean you are satisfied right?



Oh, absolutely!


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## Alexec (Jan 13, 2018)

Barmoley said:


> I have a 240 yxr7. It is actually 235x50 or so. The grind is medium weight. Food separation is good. The core steel discolors on onions quickly, slower than 52100, but definitely not stainless. It seems to do better with tomatoes and similar produce. It is semi stainless, but more reactive on onions than SS in SS itinomonn or SS gengetsu. I havent sharpened it yet, so cant comment on that. Fit and finish is good, but choil and spine are not rounded, even though they are not sharp. I like the profile and the balance with ebony handle from K&S is good.



How is the metal? Did you like it? How would you rate it?


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## Barmoley (Jan 13, 2018)

So far I like it. It is still as sharp as when it came, I only used it for a few meals so that is not saying much. I havent sharpened it, so dont know how that will go. The core cannot be treated as stainless, clading is stainless, so over all less maintenance than a carbon knife, but you do have to wash and dry after use on onions, etc


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## Alexec (Jan 13, 2018)

Barmoley said:


> So far I like it. It is still as sharp as when it came, I only used it for a few meals so that is not saying much. I havent sharpened it, so dont know how that will go. The core cannot be treated as stainless, clading is stainless, so over all less maintenance than a carbon knife, but you do have to wash and dry after use on onions, etc


Thanks for info


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## Alexec (Jan 13, 2018)

Paraffin said:


> Oh, absolutely!



Thank you mate


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## GorillaGrunt (Jan 13, 2018)

Ive got the 210 k-tip in YXR7. I dont know that it stands out above other knives in its class but it stands well with them. Frankly, I havent experienced the supposed superior edge retention of these powdered high alloy tool steels, but most of that can likely be attributed to me, i.e. professional use on plastic boards, insistence upon maximum sharpness rather than still good enough, and that I havent yet figured out the best angles and stones for these steels. Id like to try Sukenaris HAP40 at 68 HRC.


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## JDA_NC (Jan 13, 2018)

I've had a Sukenari hairline ZDP-189 240mm gyuto for around two years now.

Here are two posts showing pictures/thoughts of the knife:

http://www.kitchenknifeforums.com/s...west-knife-buy?p=392433&viewfull=1#post392433

http://www.kitchenknifeforums.com/s...THIN-240-gyuto?p=430974&viewfull=1#post430974

For me this knife 100% falls into the laser category. Very, very thin. Cuts wonderfully and has great edge retention. It was my daily driver at my last job and saw a lot of use. Doesn't really fit in with my current gig and these days I favor thicker knives overall but I wouldn't hesitate to recommend this knife to those it fits (ie, someone with fast cutting stones/experience sharpening, and the ability to use and care for a knife so thin & hard).


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## inhuman (Jan 13, 2018)

I have a Sukenari hap40 210 ktip, and I use it at work all the time . It has killer edge retention, it has heft in hand, and food release is decent . The grind is more of a workhorse grind for me . Sharpening it isnt as hard as everyone makes it out to be . I keep mine around 10-12 degrees . The handle is a k&s semi custom , very nice . Probably one of the best handles Ive had. The core steel has changed color just a little . 

Overall it is a killer knife and I would not hesitate to buy the 240 gyuto in this steel if I could ever find the damn thing . Originally I paid for the 240 suji but it turned out it was out of stock .

I also own 2 Sukenari honyaki but Id imagine they are a little different than the normal offerings . 

GorillaGrunt, look into a Sani tuff board for work . Makes a fair difference for your edge life .


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## MrHiggins (Jan 14, 2018)

I have the 240 HAP40 gyuto. I keep buying more knives, but this one is still my favorite. 

It's on the laser side of the spectrum, but is stiff as a board. A very solid feeling knife, especially for its width.

The steel is not too hard to sharpen, but it is harder that normal carbons. I'm a home cook, so I don't really know about edge retention. I bet it's awesome.

It's a boring looking knife compared to some others out there. It's just all business.

Lovely, lovely knife.


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## LucasFur (Jan 14, 2018)

Sukenari zdp-189 240 gyuto Dammy owner, 

I love it, grind is fantastic, Profile is fantastic, I would not hesitate to buy another. The board feel is like a Honyaki. Sharpening takes about 7-10x as long to get a burr than say blue steel, which is probably 2x as long to get a burr from white steel. Im not selling though, it's really a great knife for me.


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## Alexec (Jan 14, 2018)

JDA_NC said:


> I've had a Sukenari hairline ZDP-189 240mm gyuto for around two years now.
> 
> Here are two posts showing pictures/thoughts of the knife:
> 
> ...



Thank you for the information


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## Alexec (Jan 14, 2018)

inhuman said:


> I have a Sukenari hap40 210 ktip, and I use it at work all the time . It has killer edge retention, it has heft in hand, and food release is decent . The grind is more of a workhorse grind for me . Sharpening it isnt as hard as everyone makes it out to be . I keep mine around 10-12 degrees . The handle is a k&s semi custom , very nice . Probably one of the best handles Ive had. The core steel has changed color just a little .
> 
> Overall it is a killer knife and I would not hesitate to buy the 240 gyuto in this steel if I could ever find the damn thing . Originally I paid for the 240 suji but it turned out it was out of stock .
> 
> ...



Thanks very much


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## Alexec (Jan 14, 2018)

LucasFur said:


> Sukenari zdp-189 240 gyuto Dammy owner,
> 
> I love it, grind is fantastic, Profile is fantastic, I would not hesitate to buy another. The board feel is like a Honyaki. Sharpening takes about 7-10x as long to get a burr than say blue steel, which is probably 2x as long to get a burr from white steel. Im not selling though, it's really a great knife for me.



Thank you mate


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## inferno (Jan 14, 2018)

GorillaGrunt said:


> Ive got the 210 k-tip in YXR7. I dont know that it stands out above other knives in its class but it stands well with them. Frankly, I havent experienced the supposed superior edge retention of these powdered high alloy tool steels, but most of that can likely be attributed to me, i.e. professional use on plastic boards, insistence upon maximum sharpness rather than still good enough, and that I havent yet figured out the best angles and stones for these steels. Id like to try Sukenaris HAP40 at 68 HRC.



Because for kitchen knife use there is no superior edge retention. these steels are made for cutting tools in CNC-mills, drill bits, different types of dies, punches and reamers and so on. and those are not sharpened to 20degrees, its more like 45-60 degrees, or even 90 degrees. they can even be radiused at the tip.

What most people forget is that there are several different types of wear, abrasive is one, and adhesive is another, and cutting polymers will result in almost exclusively adhesive wear. 

Simple low alloyed carbons with low carbide content are good for adhesive wear, and bad for abrasive.

High carbon high alloyed high carbide content steels like hss/stainless hss/stainless with lots of Mo/V/Cr are good for abrasive wear and bad for adhesive wear.
Powder variants negate this somewhat by distributing the carbides better. Finer grained variants negate this too somewhat, also grain size is dependent on austenitization temp. and finally what genereration powder tech is used is important. the good stuff is the 2 and 3gen.

The we have "toughness", both macroscopic, like in resistance to a blade cracking completely or a big 5-10mm chip,
and microscopic, resistance to microchipping. these are 2 different things. especially on knife blades.

Many of these new "supersteels" seems more suited for a 35-40 degree edge from a 2k stone than a 15 degree edge from a 6k stone imo.
the "takes are sawtooth edge and holds it forever" category.

Anyway I took the libery to look this hap40 up. (the hss is at the bottom)
https://www.hitachi-metals.co.jp/e/products/auto/ml/pdf/yss_tool_steels_d.pdf

its closely related to uddeholm vandis 30
https://www.uddeholm.com/app/uploads/sites/43/2017/11/Riktanalyser_1711.pdf

datasheet, there is a comparison graph at the bottom. (arne is 01, sverker21 is d2)
http://www.bucorp.com/media/vanadis_30_superclean_datasheet.pdf

additional powdersteel info.
http://www.bucorp.com/media/pm_tool_steels_metalformingmagazine03.pdf


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## Eloh (Jan 14, 2018)

1. YXR7 is no PM Steel 
2. My HAP40 knife has *far* better edge retention than any of my simple carbon steel knives (Shirogami etc)
3. I sharpen it at around 30degrees up to 12k, wich works great


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## Alexec (Jan 14, 2018)

Eloh said:


> 1. YXR7 is no PM Steel
> 2. My HAP40 knife has *far* better edge retention than any of my simple carbon steel knives (Shirogami etc)
> 3. I sharpen it at around 30degrees up to 12k, wich works great



You tell hap40 is better choise than yxr7?


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## MrHiggins (Jan 14, 2018)

I have a HAP40 gyuto and my brother has a HAP40 utility knife (that he abuses every day). The steel holds up very well in both applications. It seems like very good steel. 

I don't know anything about YXR7, but I can attest for HAP40.


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## Barmoley (Jan 14, 2018)

I think there are very few people that have experience with both steels in the same knife. In addition it seems like some people feel or have more laser like grind and some medium grind. For a home cook grind and blade shape would make more of a difference than the steel, especially between these steels. Strictly from the data sheet hap40 should be more wear resistant and yxr7 should be tougher. How much this makes a difference in the kitchen type use is hard to say, since both of these are already significantly more wear resistant than the usual steels. I wanted to try yxr7 because I dont think that wear resistance greater than something like well treated blue 2 is needed. I think that most dulling in kitchen knives with enough wear resistance is due to micro chipping or edge rolling. With high hrc of these steels rolling should not be an issue, so the less likely to chip steel is interesting to me. With all that said, pick a knife from a reputable manufacturer that looks good to you and play with it.....


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## Alexec (Jan 14, 2018)

MrHiggins said:


> I have a HAP40 gyuto and my brother has a HAP40 utility knife (that he abuses every day). The steel holds up very well in both applications. It seems like very good steel.
> 
> I don't know anything about YXR7, but I can attest for HAP40.



Thank you sir


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## Alexec (Jan 14, 2018)

Barmoley said:


> I think there are very few people that have experience with both steels in the same knife. In addition it seems like some people feel or have more laser like grind and some medium grind. For a home cook grind and blade shape would make more of a difference than the steel, especially between these steels. Strictly from the data sheet hap40 should be more wear resistant and yxr7 should be tougher. How much this makes a difference in the kitchen type use is hard to say, since both of these are already significantly more wear resistant than the usual steels. I wanted to try yxr7 because I dont think that wear resistance greater than something like well treated blue 2 is needed. I think that most dulling in kitchen knives with enough wear resistance is due to micro chipping or edge rolling. With high hrc of these steels rolling should not be an issue, so the less likely to chip steel is interesting to me. With all that said, pick a knife from a reputable manufacturer that looks good to you and play with it.....



Nice thabk you for responding


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## Alexec (Jan 14, 2018)

Barmoley said:


> I think there are very few people that have experience with both steels in the same knife. In addition it seems like some people feel or have more laser like grind and some medium grind. For a home cook grind and blade shape would make more of a difference than the steel, especially between these steels. Strictly from the data sheet hap40 should be more wear resistant and yxr7 should be tougher. How much this makes a difference in the kitchen type use is hard to say, since both of these are already significantly more wear resistant than the usual steels. I wanted to try yxr7 because I dont think that wear resistance greater than something like well treated blue 2 is needed. I think that most dulling in kitchen knives with enough wear resistance is due to micro chipping or edge rolling. With high hrc of these steels rolling should not be an issue, so the less likely to chip steel is interesting to me. With all that said, pick a knife from a reputable manufacturer that looks good to you and play with it.....



From what you said, youd prefer to use yxr7 i guess?


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## Barmoley (Jan 14, 2018)

I did, so that's what I got. I haven't used hap40 though, so it is all theoretical. I am sure hap40 is great too and there are a lot more people who have experience with it.


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## inferno (Jan 14, 2018)

I managed to roll the edge of my brand new jck vortex r2 santoku just now. Took me 5 minutes on a zwilling plastic board  
First time I used it... Its a very thin blade towards the edge though. I can feel it as a very minor burr about 1 inch long. 
I cut the exact same stuff with my brand new kurosaki in aogami super, and it did not roll nor chip, nor dull in any way. But it was only half as sharp to begin with from the factory.
This was with the factory edges. I don't like to baby my knives so I will have to put on a much more durable edge angle on the vortex.

Am I surprised that high hrc powder "super steel" at shallow angles aint always that super (on plastic at least)? Not at all.
To me, the only true "super steel" is blue 2 
vortex to the right and kurosaki as to the left.


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## Alexec (Jan 14, 2018)

inferno said:


> I managed to roll the edge of my brand new jck vortex r2 santoku just now. Took me 5 minutes on a zwilling plastic board
> First time I used it... Its a very thin blade towards the edge though. I can feel it as a very minor burr about 1 inch long.
> I cut the exact same stuff with my brand new kurosaki in aogami super, and it did not roll nor chip, nor dull in any way. But it was only half as sharp to begin with from the factory.
> This was with the factory edges. I don't like to baby my knives so I will have to put on a much more durable edge angle on the vortex.
> ...



Nice knives you got there


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## Alexec (Jan 14, 2018)

Barmoley said:


> I did, so that's what I got. I haven't used hap40 though, so it is all theoretical. I am sure hap40 is great too and there are a lot more people who have experience with it.



Sad things I cant find any on sale. Neither sukenari hap40 or yxr7


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## panda (Jan 14, 2018)

what the heck is yxr7, reads to me like a motorcycle model


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## Alexec (Jan 14, 2018)

panda said:


> what the heck is yxr7, reads to me like a motorcycle model



Is a high powdered steel, kinda new to the market. 
Seems like yzf  I do own one tho I cant use her on road


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## GorillaGrunt (Jan 14, 2018)

inferno said:


> Because for kitchen knife use there is no superior edge retention. these steels are made for cutting tools in CNC-mills, drill bits, different types of dies, punches and reamers and so on. and those are not sharpened to 20degrees, its more like 45-60 degrees, or even 90 degrees. they can even be radiused at the tip.
> 
> What most people forget is that there are several different types of wear, abrasive is one, and adhesive is another, and cutting polymers will result in almost exclusively adhesive wear.
> 
> ...



Aha, I had been coming to that conclusion empirically, thanks for providing some support. Not to say these arent good steels or good knives - just that expecting them to do something that Blue, SLD, R2, etc. dont might run into magical thinking.


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## Alexec (Jan 14, 2018)

GorillaGrunt said:


> Aha, I had been coming to that conclusion empirically, thanks for providing some support. Not to say these arent good steels or good knives - just that expecting them to do something that Blue, SLD, R2, etc. dont might run into magical thinking.



You prefer blue and r2 yourself?


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## Barmoley (Jan 14, 2018)

YXR7 is not powdered metallurgy steel, it is matrix high speed steel. Supposed to be tougher and more wear resistant than SLD at the same or even higher HRC. James has a very good description of it on his site where he sells these knives. How the attributes of the steel translate into the knife performance is a difficult question to answer. However, clearly there is a difference of some sort among different steels, otherwise everyone should just use one flavor of steel for all kitchen knives.


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## HRC_64 (Jan 14, 2018)

panda said:


> what the heck is yxr7, reads to me like a motorcycle model



I had the same reaction, here is the brochure from hitachi for those interested. 

http://www.hitachimetals.com/materials-products/speciality-steel/documents/YXRseries.pdf

"Tougher than existing high-hardness steels, 
but harder than existing high-toughness steels."

It sounds like a PITA to sharpen, but maybe they have that
figured out some how....


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## Barmoley (Jan 14, 2018)

Here http://www.knivesandstones.com/sukenari-yxr7-hsts-gyuto-21cm/ look in description.

James says it is not too difficult to sharpen. Anyway, like I said somewhere above, pick a knife from a reputable maker, dealer and use it. Any quality knife will give you excellent performance and in the process you will figure out what you like. Steel should be the last factor when picking out of all these just decide carbon or stainless and go from there.


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## panda (Jan 14, 2018)

hitachi should make a knife steel that is 'easiest in the world to sharpen'


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## inhuman (Jan 15, 2018)

panda said:


> hitachi should make a knife steel that is 'easiest in the world to sharpen'



They already did , white #1!


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## GorillaGrunt (Jan 15, 2018)

Barmoley said:


> Steel should be the last factor when picking out of all these just decide carbon or stainless and go from there.



Good advice. I did assume YXR7 was PM steel because many of the high alloy high speed tool steels are - oops! All I meant to say was that I may have had unrealistic expectations based on an incomplete understanding of metallurgical properties as applied to kitchen knife performance, and infernos information jibes with my observations.



Alexec said:


> You prefer blue and r2 yourself?



Well, my favorite knives so far happen to be blue, R2, and an unspecified semi stainless steel but also a few in white 2 and 
others; see Barmoleys point above. My Sukenari is a very good knife, Id recommend it to someone, and they offer a wide range of steel options. As a note I havent found any specific steel particularly onerous or frustrating to sharpen.


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## Eloh (Jan 15, 2018)

In my experience Sukenari HAP40 edge retention is significantly higher than any simple carbon steels i'ver used, like multiple times as long.


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## Alexec (Jan 15, 2018)

GorillaGrunt said:


> Good advice. I did assume YXR7 was PM steel because many of the high alloy high speed tool steels are - oops! All I meant to say was that I may have had unrealistic expectations based on an incomplete understanding of metallurgical properties as applied to kitchen knife performance, and infernos information jibes with my observations.
> 
> 
> 
> ...



Nice. Thanks for multiple responses


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## Alexec (Jan 15, 2018)

Eloh said:


> In my experience Sukenari HAP40 edge retention is significantly higher than any simple carbon steels i'ver used, like multiple times as long.



HaP40 really seems like a good investment


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## StonedEdge (Jan 15, 2018)

inhuman said:


> They already did , white #1!


+1!


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## Eloh (Jan 15, 2018)

Yeah and most Japanese knives use it (or #2) wich is unfortunate


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## inferno (Jan 15, 2018)

HRC_64 said:


> I had the same reaction, here is the brochure from hitachi for those interested.
> 
> http://www.hitachimetals.com/materials-products/speciality-steel/documents/YXRseries.pdf
> 
> ...



I raise you one datasheet
http://www.hitachi-metals.co.jp/e/products/auto/ml/pdf/cwts_b.pdf


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## HRC_64 (Jan 15, 2018)

inferno said:


> I raise you one datasheet
> http://www.hitachi-metals.co.jp/e/products/auto/ml/pdf/cwts_b.pdf




One interesting tidbit in there:

Hap40 (C+) is graded worse for machine-abilty vs YXR7 (B), 
while YXR7 (B) grades as worse for distortion during HT vs Hap40 (A).


This might make it more production friendly,
as well as user friendly, in terms of sharpen-ability.

Have no idea about grain and carbide size, edge stability issues, 
but maybe someone will chime in with that if they've seen it.

____________________

edit: on the HSS datasheet, YXR7 and Hap40 both grade 'C' for machinabilty...hmmmmm 
.... see p.4, lower table:

https://www.hitachi-metals.co.jp/e/products/auto/ml/pdf/hsts_b.pdf


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## HRC_64 (Jan 15, 2018)

Here's another thread on this steel...Looked like a passaround with a big following that never happened.
http://www.kitchenknifeforums.com/s...-steel-new-knife-passaround-YXR-7-210mm-Gyuto

included this comment as well with a potential achilles heel for this alloy (they all seem to have one...)




Chicagohawkie said:


> Did they find a way to make that steel less corrosive? I remember years ago the tactical knive makers toyed with this steel but it was highly reactive and it just kinda went away.


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## inferno (Jan 15, 2018)

HRC_64 said:


> One interesting tidbit in there:
> 
> Hap40 (C+) is graded worse for machine-abilty vs YXR7 (B),
> while YXR7 (B) grades as worse for distortion during HT vs Hap40 (A).
> ...



machinability refers to the spherodized annealed state, the softest and most machinable one, basically the "grain" in transformed to small balls that easily shaves off.
You dont machine hardened tool steel. you machine it, stess relieve it, normalize it, austenize it, quench it, cryo it (sometimes), temper it (twice or 3 times), then you grind it to final shape, 
usually you leave 0,1-0,3mm or so to grind off after hardening. and this is where the distortion comes in. You need to know how much it will shrink in one direction (if any) and elongate in the other during hardening.

these steels are quenched in air/between metal plates/vacuum/forced air/molten salt/molten metal (multi stage quenches) and so on in knife thicknesses. They are all "air hardening" in knife thickness. some may at the very most get a quick dunk in hot oil then up in the air again to cool down to room temp. but they would most likely all crack when using oil/water/brine the regular way. so "distortion" isnt really an issue. Usually only really agressive quenches distort steel.

Grindability refers to how easy it is to grind it with rotating discs when hardened and tempered, measured in like mm/minute removed for a certain size pice or similar.

Polishability refers to how easy it is to get a mirror polish on hardened pieces for molding tools. pretty much all powder steels polish like crap, and some blades polish worse than others, and those are stonewashed/epoxy coated/sand blasted and so on (on regular knives I mean).

Grain and carbide size isn't that important for HSS, they are usually designed for fast spinning or punching or slicing rotating tools at elevated temps, like 500C or so. Whats more important is "temper resistance" at these temps, that is how fast it will soften and get useless. Hardness at these temps, and strength at these temps, and resistance to cracking, resistance to abrasion from other steels like 304SS and so on. Lubricity when punching and such.

Also these steels are almost always tempered at 550C or close to it, since here, the 50% or so retained austenite (yeah thats no joke) after the quench gets transformed to untempered martensite and carbides. This is what you have to temper these 2 or 3 times, since you get untempered martensite with the first temper. Untempered martensite is brittle like glass.

also they are almost always nitrided/carbonitrided/nitrocarburized as the finished products. and this is usually done at 550C or thereabout. So its convenient to combine these 2 stages.

Also it was a few years ago I read my books about this by I'm fairly certain hss genereally works like this: the steel matrix (the martensite) get softer just like a simple carbon steel does when the tempering temp gets higher, and softer equals weaker matrix, but since you get carbide growth the measured hardness takes a dive and then it rockets up again (since the carbides are very very hard, and high in volume), tjis is called "secondary hardening", 2 hardness peaks at 2 different tempering temps. only difference is that with a 200C temper all the hardness comes from hard strong martensite, whereas the 550C hardness is a soft and weak martensite gluing together all those carbides (and there is lots of carbide% in hss, this is their sole reason for existing). Soo sometimes the matrix is too soft and weak to simply hold on to these carbides, so they tear out at. Carbides always reside at grain boundaries.

And actually they dont tear out, the matrix/martensite around them gets abraded away since its soft and weak, and they fall out. the thinner the edge, the sooner this happens. but then again these steel were never intended for sharp edges so this is not a problem, for the industrial users that is.

Carbide size?? I'm guessing the size of a small bumblebee or so  no just kidding but these are multimetal carbides and they can possibly get pretty large, depending on process temperatures, ingot or powder, alloying %, C% and so on.

Also these steel steels are really really really sensitive to correct temperatures and process times.

Yeah IIRC this is approximately how it works in broad strokes. kinda.


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## Alexec (Jan 15, 2018)

inferno said:


> machinability refers to the spherodized annealed state, the softest and most machinable one, basically the "grain" in transformed to small balls that easily shaves off.
> You dont machine hardened tool steel. you machine it, stess relieve it, normalize it, austenize it, quench it, cryo it (sometimes), temper it (twice or 3 times), then you grind it to final shape,
> usually you leave 0,1-0,3mm or so to grind off after hardening. and this is where the distortion comes in. You need to know how much it will shrink in one direction (if any) and elongate in the other during hardening.
> 
> ...



Too much intel, my brain is going to explode!
I cannot find those in europe


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## Kippington (Jan 15, 2018)

Sounds about right to me. I learned a bit too! :doublethumbsup:

I find it hilarious when vendors advertise a knife as _ohmahgosh_ *HIGH SPEED STEEL!!!* I begin to imagine an uber Rick Theory moving the knife at such a blurring speed that the cutting board starts to smoke and the food starts to sear as the knife reaches multiple times the temperature of boiling water... but never fear, the steel was engineered to hold up to _precisely_ this moment! :lol2:



inferno said:


> ...the steel matrix (the martensite) gets softer just like a simple carbon steel does when the tempering temp gets higher, and softer equals weaker matrix...



One thing to mention is during the secondary/precipitation hardening, the iron stays hard as more martensite is formed from the retained austenite in the first temper. During any subsequent tempering, the dislocations in the iron matrix get blocked from moving by the precipitation carbides (which create their own dislocations too), leaving the steel much harder when compared to a simple carbon steel that got tempered at the same temperature. So while I agree that the carbides are harder then the surrounding matrix, I would argue that the iron itself is not soft.


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## Barmoley (Jan 15, 2018)

Thanks for all the metallurgy info, I really like learning this stuff. As far as sukenari YXR7 is concerned, Ive had limited experience with one knife. So far in my kitchen use, it is less reactive than simple carbon steels such as 52100, white 2, or blue 2. It is more reactive than gengetsu SS or itinomonn SS. Not sure about tactical guys years ago, but their goals and criteria are very different, so I dont know what they compared it to when they said it was very corrosive. I dont see how it can be more corrosive than 1095, 5160, L6, 52100, etc. YXR7 has relatively low amount of carbon at 0.8 and relatively low amounts of carbide forming elements as compared to some PM steels. None of the existing steels are magic, so as long as expectations are reasonable, some steels perform better than others. HSS steels can make good knives, cpm-m4 used to be all the rage for cutting competitions, so at least in that format it did great. It seems that hap40 performs well for some members, so there is that to. Anyway, I wouldnt disregard the steel just because it was not designed for a kitchen knife, since most were not. James makes a pretty good case for sukenari YXR7 and he seems to know his stuff.


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## Kippington (Jan 16, 2018)

Barmoley said:


> I wouldnt disregard the steel just because it was not designed for a kitchen knife, since most were not.



You misunderstand my post. It's not the steel that I'm talking about, it's the marketing. There is really never a 'right' time to highlight that that a kitchen knife is is made specificly from a High Speed Steel. 
It's like if I made a knife out of piano-wire grade high carbon steel - lets call it SteelX. It would probably make a good knife, but to sell it as a chef's knife made out of 'music-wire quality steel' instead of just 'SteelX' would be a tad silly, wouldn't you say?


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## panda (Jan 16, 2018)

kip when will you be working with W2 steel again?


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## Barmoley (Jan 16, 2018)

I get what you are saying, but it is done all the time. 

5160, L6 - spring steel
52100 - ball baring steel
AEB-L - razor blade steel, even though maybe somewhat relevant in this case
SRS-15, M4, YXR7 - High speed steel

So you are absolutely correct that advertising that a kitchen knife is made out of high speed steel is somewhat irrelevant, but it is not unique to this situation. I am just trying to say that as much as you shouldnt use high speed as a selling point, you shouldnt disregard it just because it is high speed


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## Drosophil (Jan 16, 2018)

Barmoley said:


> So you are absolutely correct that advertising that a kitchen knife is made out of high speed steel is somewhat irrelevant



Unless you can chop really, _really_ quickly :tongue2:

Edit: Nevermind, I've just seen Kip's post.

On a different note, I don't remember seeing "low alloyed steel" advertised anywhere for knives. I'm guessing because "low" gives it a bad connotation.


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## Kippington (Jan 16, 2018)

Barmoley said:


> 5160, L6 - spring steel
> 52100 - ball baring steel
> AEB-L - razor blade steel, even though maybe somewhat relevant in this case
> SRS-15, M4, YXR7 - High speed steel



But Barmoley you have to admit, high speed steels are mentioned far more often than the rest.
Of all your examples:

There's only one that gets it's own commonly used abbreviation (HSS)
It's the only one that gets added into a series name (Tojiro HSPS, I'm still waiting for the Kramer Ball-Bearing Series!)
Many sites list HSS differently from the rest.
For example, if you go to https://japanesechefsknife.com and take a look under 'Blade Steel', you'll get three categories: Stainless Steel, Carbon Steel and Powdered High Speed Tool Steel...
I never see the others (spring, ball bearing or razor blade steels) get mentioned as often, or in the same capacity as this.



panda said:


> kip when will you be working with W2 steel again?


Not for a long while! I recently bought enough 1095 to make about 16 full size gyutos, then spent the rest of my money on a Paragon heat-treating furnace and endless 2x72" belts. This 'hobby' is getting expensive, but the for the next few months I'm gonna have some fun! :laugh:


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## Eloh (Jan 16, 2018)

Sure it's marketing, but it kinda makes sense to mention the name (HSS), since High Speed Steels have high abrasion resistance, wich is something a lot of people desire in a knife.


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## Barmoley (Jan 16, 2018)

Kippington said:


> But Barmoley you have to admit, high speed steels are mentioned far more often than the rest.
> Of all your examples:
> 
> There's only one that gets it's own commonly used abbreviation (HSS)
> ...



Once again Kip, I dont disagree with you, just dont see it as that different from anything else, it is all marketing. Some HSS make great knives, some low alloy steels make great knives. Low alloy is mentioned indirectly when steels purety is considered a good thing, or even mentioning high carbon or tool steel. What do these really tell you?
My sugggestion was pick carbon or stainless and a reputable maker or dealer and go from there. We are all knife geeks, so we tend to over think this, but this is what makes it interesting for some of us. Otherwise, I could be fine with any one of many of my knives, any one of them is much, much more than I need:biggrin:

Sukenari YXR7 is a good knife. Is it better because it is made out of this particular HSS vs 1095? I dont know. I didnt care that the steel was HSS specifically, but Jamess description of its toughness at high hardness and his experience with it did.


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## GorillaGrunt (Jan 16, 2018)

What else would you call the category? It includes stainless and non, and is distinct from the other semi stainless tool steels, and theyre not all powdered - is there another description that would comprise the same set of steels?


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## Kippington (Jan 16, 2018)

I guess that's the thing: Their unifying distinction is a property that we will never put any knife through, yet it's considered a major knife category for that trait alone.

It would be like making cars out of aerospace materials (which would be great, I'm sure), then classifying them as 'aerospace cars'.
Maybe it's just me, but I find it kinda backwards! :razz:


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## Eloh (Jan 16, 2018)

Well, no it's not a category for that trait alone, it just happens to be the name of an existing steel category. Another major trait of HSS happens to be high abrasion resistance, wich is very significant (to some).

The thing is, there really are not a lot of steels made specifically for knives AND high edge retention, because the 'knife nerd market' simply isnt big enough for major steel companies to give a f 

Hence makers use what already exist and is avaible, wich are mainly High Speed Tool Steels. Sure i dont need any cobalt in my HAP40 knife but it doesnt hurt either since i want the Tungsten and Vanadium.  

I'm sure if it would be easily avaible to them Sukenari might use M2 (wich is basically HAP40 without Co) too.


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## inferno (Jan 16, 2018)

Kippington said:


> But Barmoley you have to admit, high speed steels are mentioned far more often than the rest.
> Of all your examples:
> 
> There's only one that gets it's own commonly used abbreviation (HSS)
> ...



But there are more categories imo. Not just carbon/SS/hss.

stainless can be divided into stainless and stainless hss i think. and also powder ss.
carbon in the biz refers to unalloyed carbon (or possibly a dash on Mn in there).
but then there is low alloyed carbon steel with half a % of this and that.
High alloyed with several % of 1 or more elements.
also could be classified as oil/air/water hardening.

then tool steels, and these can be hot work/cold work/shock resistant/hss/semi ss like d2

Carbon steel for me is unalloyed or at the very most low alloyed steel. but even hss could be called carbon if one really wanted since its not stainless.

I think jck makes it easy for them to simply have 3 categories, and category 3 could just as well have been called "supersteel"  where they could lump anything out of the "ordinary" into.


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## Bensbites (Jan 16, 2018)

What I am about to point out, I dont consider it a negetive, just s fact. The softer cladding on a hap40 can scratch real real easily. Some people care more than I do.


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## SurlyBastage (Feb 20, 2018)

For the 240mm Sukenari gyutos from James, how does the SG2 (R2) compare to the Ginsanko?


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## Eloh (Feb 20, 2018)

Well the grind is probably very similar, if not the same. Steelwise the R2 has better edge retention but is probably a little more brittle, depending on sharpening angle.


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## LucasFur (Feb 20, 2018)

Eloh said:


> Well the grind is probably very similar, if not the same. Steelwise the R2 has better edge retention but is probably a little more brittle, depending on sharpening angle.



I would say the same thing. Probably very similar if not the same. 
it depends on what is important to you. Ginasn's penetrability and suppleness. or R2's edge keeping abilities. .... kinda like a white vs blue super discussion.


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## SurlyBastage (Feb 20, 2018)

LucasFur said:


> ...it depends on what is important to you. Ginasn's penetrability and suppleness. or R2's edge keeping abilities.



What is penetrability? 

This will be my first j-knife so I have no reference for these steels. 

For R2 holding an edge longer, how does this translate with respect to how often a typical home chef needs to sharpen and is there a significant difference in ease of sharpening? 

For the brittleness, how significant is the difference?


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## inzite (Feb 20, 2018)

SurlyBastage said:


> What is penetrability?
> 
> This will be my first j-knife so I have no reference for these steels.
> 
> ...



if u go r2 u won't need to sharpen it more than twice a year at most. unless you slice paper towels everyday to check ultimate sharpness.


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## SurlyBastage (Feb 20, 2018)

About how often would I need to sharpen the ginsan?


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## panda (Feb 20, 2018)

SurlyBastage said:


> *What is penetrability? *
> 
> This will be my first j-knife so I have no reference for these steels.
> 
> ...



&#129315;&#65533;&#65533;&#129315;


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## SurlyBastage (Feb 23, 2018)

I hope my questions were not a thread killer.


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## LucasFur (Feb 23, 2018)

SurlyBastage said:


> About how often would I need to sharpen the ginsan?


Answered before and will be answered again, so Ill Bite. 

If the R2 would last you 6 months. The Ginsan would last 1 month. I will admit my downfall there and say dont have much experience with ginsan, somewhat making the conclusion on how similar edge retention AS and R2 are and feel that i have found between ginsan and white steel. both white and blue i have more experience with. 

Sharpening angle, blade thickness, heat treat, and Grind dependent. (Probably other factors also) 

Honestly bastage, It looks like your considering either one. So my thoughts, with 30 or so "mid to higher end" blades under me I would argue that every collector, knife head, should have (or had) a R2 blade, especially if you see this hobby as a means to an end, that end being great knife to ride into the distance with somewhat forget in a year that you even registered on KKF. If kitchenknives are more of a long term hobby, one which you see yourself getting immersed in, buying stones, knives etc. and having KKF as your home page, get the ginsan. dont know if the others will agree or not, but its my take. Cheers :knife:


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## SurlyBastage (Feb 24, 2018)

Thanks for your take, it is quite helpful. 

I am considering(obsessing over) a 240mm Sukenari ginsan or R2 gyuto along with some others. I have a dormant what knife thread that I plan to revive soon. 

I just got my stones. I plan to start learning to sharpen and get two good boards before getting the knife. 

I hope to just get a few different types of knives and not get bitten by the collecting bug but who knows. 

It has not been easy to find as many thoughts on the Sukenaris as others like the Tanakas or Gesshins so I was excited to see this thread.


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## parbaked (Feb 24, 2018)

James explained the difference between the Sukenari and Tanaka Ginsan as follows: 
"_Tanaka Ginsan is exclusive to K&S and exteremely thin behind the edge. The cuttng performance is unrivaled in its category, and it is a true forged knife. 
The Sukenari ginsan is not as thin as the Tanaka but is probably more suitable for users who just get into the Jknife world as the Tanaka is more delicate than the Sukenari (prone to chipping compared to the sukenari)."_

Also I am pretty sure that the Sukenari Ginsan K&S is a stamped blade which might partially explain why it's more economical than the Tanaka.


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## chinacats (Feb 24, 2018)

I've not owned a Sukenari so take this with a grain of salt but if you don't see much about certain knives around here there may be a reason why...that said, I know some here use and like these. 

As to how long between sharpening, other factors not mentioned above are type cutting board, cutting style, what and how much you cut and somewhat more importantly how well do you sharpen and what do you consider sharp? 

Both are quality steels.


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## parbaked (Feb 24, 2018)

One reason that Sukenari is not as well known is that they are based in Toyama which is quite isolated and not at all a knife making center like Seki, Sakai, Niigata or Sanjo. 
As the only knife maker in Toyama, they focused on selling within their region until they were discovered by outside distributors. I think its more to do with that then the quality of their work.
James has a nice write up of his visit: http://www.knivesandstones.com/blog/visiting-sukenari-hamono-apr-2016/


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## SurlyBastage (Feb 28, 2018)

parbaked said:


> James explained the difference between the Sukenari and Tanaka Ginsan as follows:
> "_Tanaka Ginsan is exclusive to K&S and exteremely thin behind the edge. The cuttng performance is unrivaled in its category, and it is a true forged knife.
> The Sukenari ginsan is not as thin as the Tanaka but is probably more suitable for users who just get into the Jknife world as the Tanaka is more delicate than the Sukenari (prone to chipping compared to the sukenari)."_



Being a newbie, that should steer me toward the Sukenari R2 or ginsan, yet the unrivaled comment draws me to the Tanaka.

Parbaked, thanks for the link. I had read it previously but I enjoyed revisiting it.


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## MrHiggins (Mar 1, 2018)

From my limited experience (I own a 240 hap40), Sukenari is just too good as to be boring. 

What I mean is that the knife has no "Wabi Sabi". It is surgically precise. It has the perfect balance between thinness and stiffness, as if a committee designed it. It has very little soul.

I don't want it to be, but it's my favorite knife that I own, from a functionality perspective (which is all that matters in the long run for me). It's a killing machine that has absolutely no desire to get in touch with its feelings, or write a poem, or enjoy the sunset with a girl around its arm.

I would buy mine again in a heartbeat.


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## Barmoley (Mar 1, 2018)

You sir are a romantic and a poet:doublethumbsup:

I whole heartedly agree mine yxr7 is so good for me, I don't know what I would change about it. It doesn't really have any quirks and doesn't require me to adjust and adopt to it.


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## labor of love (Nov 17, 2019)

After all these years I still can’t fully commit to buying a particular Sukenari. Lately I’ve been considering this R2 line.
https://japanesechefsknife.com/prod...lad-wa-series-wa-gyuto-210mm-to-270mm-3-sizes

Knife is forged, yet sold at moderate price. R2 seems to offer very good retention without being too difficult to sharpen for me.
Handles are not blingy which is a plus.
Thoughts?


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## Carl Kotte (Nov 17, 2019)

labor of love said:


> After all these years I still can’t fully commit to buying a particular Sukenari. Lately I’ve been considering this R2 line.
> https://japanesechefsknife.com/prod...lad-wa-series-wa-gyuto-210mm-to-270mm-3-sizes
> 
> Knife is forged, yet sold at moderate price. R2 seems to offer very good retention without being too difficult to sharpen for me.
> ...



I had the exact same thought and decided to try it out a couple of weeks ago. It was a 210 (the only size available in the physical store). I held it for 2 minutes and left the store without it.


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## labor of love (Nov 17, 2019)

Carl Kotte said:


> I had the exact same thought and decided to try it out a couple of weeks ago. It was a 210 (the only size available in the physical store). I held it for 2 minutes and left the store without it.


Haha! Why is that?


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## Carl Kotte (Nov 17, 2019)

labor of love said:


> Haha! Why is that?



Not sure I have anything interesting to say. It didn’t say ’-Buy me! Buy me! Buy me!’ so I felt ok leaving it. [emoji16]


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## captaincaed (Nov 17, 2019)

Sometimes I think we make this hobby harder than it needs to be. I've had my Sukenari ZDP for a year and never sharpened it. Knife just wants to work. We complain for hours about TF F&F, then buy them anyway, and overlook something like this that's properly finished?
Grind is clean, nice flat spot profile, polished spine and choil, hard steel both pedestrian and exotic. What's not to like? It's a good knife.
It's a knife that's grown on me. Did seem a bit surgical out of the gate, but I keep grabbing it.
And yes, I also bought a TF, god help me.


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## Carl Kotte (Nov 17, 2019)

Sukenari is still on my list though. The one I looked at was r2. Zdp would be fun to try. In the future... [emoji5]


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## Nemo (Nov 17, 2019)

I have a Sukenari YXR7 270mm K-tip which I mainly use for slicing roasts.

It has a pretty flat profile (Duh- being a K-tip) and a fairly thin but not laser thin grind. There is a convexity to the blade face. I can't really comment on food release because I haven't used it in a role that allows me to compare food release. I bought it in a KnS Black Friday sale a year (or was it 2?) ago and it came with a pretty nice handle and saya.

The blade finish is pretty basic, like maybe 400-600 grit. But you do tend to pay a fair bit more for the polished Sukenaris. The core steel has only taken on the barest patina despite being used repeatedly on warm meat. The spine and choil wer e nicely finished in the KnS style.

I have sharpened it once and it is indeed reminiscent of sharpening my Yoshikane SKD, which is to say that it is very pleasant to sharpen with nice feedback. Importantly, I found it easy to deburr (I was worried that being a tougher steel, it migh be a pain to deburr).

I wanted to try YXR7 to see if it would cope better with slicing crusty roasts. It does seem to be much more resitant to chipping on crusty roast (and, if I'm honest, the occasional glancing contact with a fork) than my other slicers which are blue2 and super blue. In my use, edge retention in this role seems significantly longer than my other slicers.

And yeah, YXR7 is NOT a PM steel.


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## Miles (Nov 17, 2019)

I have a Sukenari ZDP. It does hold an edge. I give it a light tune-up now and again and it keeps going. It's well crafted. It took a spot in my every day rotation and hasn't left for three years. The only other which has never left my every day kit is my Misono Swedish suji.


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## panda (Nov 17, 2019)

labor of love said:


> After all these years I still can’t fully commit to buying a particular Sukenari. Lately I’ve been considering this R2 line.
> https://japanesechefsknife.com/prod...lad-wa-series-wa-gyuto-210mm-to-270mm-3-sizes
> 
> Knife is forged, yet sold at moderate price. R2 seems to offer very good retention without being too difficult to sharpen for me.
> ...


i hate R2


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## captaincaed (Nov 17, 2019)

It’s a chore to sharpen


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## Michi (Nov 17, 2019)

captaincaed said:


> It’s a chore to sharpen


I don't find it that bad. It's slower than shirogami or aogami, but not particularly difficult, IMO. Just takes a little longer.


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## labor of love (Nov 17, 2019)

If r2 is the same thing as sg2 then y’all need to try blazen or takamura. It’s good stuff.


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## captaincaed (Nov 17, 2019)

Michi said:


> I don't find it that bad. It's slower the shirogami or aogami, but not particularly difficult, IMO. Just takes a little longer.


Sure. Not different in concept, but takes long. A chore not a pleasure


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## Barmoley (Nov 17, 2019)

labor of love said:


> If r2 is the same thing as sg2 then y’all need to try blazen or takamura. It’s good stuff.


R2 is the same thing as sg2


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## labor of love (Nov 17, 2019)

Everybody has lost their damn mind


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## Barmoley (Nov 17, 2019)

Not disagreeing but what specifically about? That it is hard to sharpen?


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## labor of love (Nov 17, 2019)

Barmoley said:


> Not disagreeing but what specifically about? That it is hard to sharpen?


YES!!!! Haha haha


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## Barmoley (Nov 17, 2019)

labor of love said:


> YES!!!! Haha haha


Yeah, never thought it was hard to sharpen, but it is all relative I guess, wh2 is easier.


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## LucasFur (Nov 17, 2019)

I think it also matters how big of a micro-bevel your working with. And angle of sharpening. 
R2 is my favourite.


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## Carl Kotte (Nov 18, 2019)

My experience of sharpening r2 has been great so far. In particular takamuras


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## M1k3 (Nov 18, 2019)

I'd rather sharpen R2 than Shun VG-10.


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## captaincaed (Nov 18, 2019)

Apparently Panda and I have a couple things in common. Ho handles and carbon steel please!


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## gclgary (Nov 18, 2019)

I Would like to try Sukenari ZDP 189 and HAP 40 knives one day!


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## Paraffin (Nov 18, 2019)

gclgary said:


> I Would like to try Sukenari ZDP 189 and HAP 40 knives one day!



I have a Sukenari 165mm petty in HAP 40 and it's a great knife. I mostly prefer carbon knives for my own use, and this Sukenari is mainly used by my wife as a replacement for a Henckel 6" utility knife. But I'll grab it for things like slicing large amounts of citrus like oranges or lemons where I want to spare the acid exposure with my carbon knives. 

Great little knife with a good slightly convex grind, fairly easy to sharpen. Excellent fit and finish on the ebony handle. As a "semi-stainless" steel, the HAP 40 under the cladding line forms a slightly more darkened patina than the stainless steel above it, which is an interesting look.


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