Carbon steel knives problem

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Perzua

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Hello,

I have a problem with my carbons. My first Japanese knive was JCK Natures Blue Moon Series BM-3 Wa Santoku 170mm & combo stone 1000/6000 also from JCK and that was a gamechanger but my other knives where really crap. Now I have Toyama petty and feels nice in hand. Im a serious home cook. To the point !

I cut 8 kg vegetables per week and carbos dull after this job (whipe often during tasks). On the other hand HAP40 is about month or more ! Maybe im doing something wrong ? I sharpen carbons on stones and powder steel knives on diamonds.


Other gear: Hasegawa, Ashi boards, JNS Aoto Matukusuyama, JNS 1000 Matukusuyama, JNS 300 Matukusuyama, JNS 6000 Matukusuyama

I stopped on Aoto and leather.

Please tell me it is normal or im doing someting wrong ? About 8 kg vegetables at home its too much ? I read somewhere (this forum) edge retention is marginal between carbons and powder steels.


Sorry for my language,
Lukas
 

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My wild guess would be the board is a factor. But I don't know about your Ashi. When used with a synthetic board, my carbons suffer terribly. Excepted for a 64-65Rc Aogami Super with a very conservative edge.
 
My first guess would be that it sounds right, assuming the edge can be brought back by quick stropping on your highest grit.
 
Benuser said:
My wild guess would be the board is a factor. But I don't know about your Ashi. When used with a synthetic board, my carbons suffer terribly. Excepted for a 64-65Rc Aogami Super with a very conservative edge.
Click to expand...

I have oak board. I will try. Thanks you

Bensbites said:
My first guess would be that it sounds right, assuming the edge can be brought back by quick stropping on your highest grit.
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Stropping on leather with paste refresh edge nicely but powdered steel dont need it.
 
Perzua said:
I stopped on Aoto and leather.

Please tell me it is normal or im doing someting wrong ? About 8 kg vegetables at home its too much ? I read somewhere (this forum) edge retention is marginal between carbons and powder steels.
Click to expand...

Hap40 is going to be more wear resistant than carbon for sure.

It seems you've got the right tools, and 8 kg of vegetables (perhaps unless it's 8 kg of very acidic limes) shouldn't really be dulling a carbon blade to the point where it struggles to cut through tomatoes and other difficult produce. If your definition of sharp is passing the hanging hair test 5 (splitting a hair on contact) then sure, 8 kg of veggies might dull the edge for that.

Personally, what I noticed is that the cleaner I got my bevels, the longer they lasted. So if your sharpening angle is slightly inconsistent and you have a rounded bevel for an edge - it'll be sharp initially but quickly roll or blunt after some time.

That's my diagnosis here - just keep working on sharpening technique, ditch the strop, and make sure you're getting crisp edges with lots of teeth on that aoto.
 
I realize there are multiple dynamics at play here and I am not sure has anybody mentioned what angle the knife is sharpened at?? I have some carbons and powered steel knives. The carbons are mostly 59 to 60 HRC . And for best edge retention on my carbons I don't sharpen under 20 degrees of angle. Interesting thread just wanted to contribute.
 
matchplay18 said:
I realize there are multiple dynamics at play here and I am not sure has anybody mentioned what angle the knife is sharpened at?? I have some carbons and powered steel knives. The carbons are mostly 59 to 60 HRC . And for best edge retention on my carbons I don't sharpen under 20 degrees of angle. Interesting thread just wanted to contribute.
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You mean 20° per side?
I sharpen 59-60Rc as almost all of my knives 25-30° inclusive.
 
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Perzua said:
Hello,

I have a problem with my carbons. My first Japanese knive was JCK Natures Blue Moon Series BM-3 Wa Santoku 170mm & combo stone 1000/6000 also from JCK and that was a gamechanger but my other knives where really crap. Now I have Toyama petty and feels nice in hand. Im a serious home cook. To the point !

I cut 8 kg vegetables per week and carbos dull after this job (whipe often during tasks). On the other hand HAP40 is about month or more ! Maybe im doing something wrong ? I sharpen carbons on stones and powder steel knives on diamonds.


Other gear: Hasegawa, Ashi boards, JNS Aoto Matukusuyama, JNS 1000 Matukusuyama, JNS 300 Matukusuyama, JNS 6000 Matukusuyama

I stopped on Aoto and leather.

Please tell me it is normal or im doing someting wrong ? About 8 kg vegetables at home its too much ? I read somewhere (this forum) edge retention is marginal between carbons and powder steels.


Sorry for my language,
Lukas
Click to expand...
You're not wrong, just discovering how stainless is superior in nearly every way except sentimentality and ease of sharpening 😤 welcome to the Stainless 20s y'all
 
Which HAP40 knife are you comparing against? Sukenari's knife retains it's edge a lot longer than the white steels for sure. I don't think all HAP40's are the same.

Edit: Just to clarify, the 4:1 wear rate you are comparing actually seems pretty good for the carbon steel compared to HAP40.
 
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Like others have mentioned make sure you are deburring completely and your edge is not rounded, but it is not that surprising for hap40 edge to last a lot longer than white 2 for example. Most hap40 is heat treated very hard, it is much more wear resistant and is tougher at the same hardness. Depending on which carbon knives you are comparing to and how exactly they blunt (is the edge chipping, rolling, deforming, just wearing out) it might be perfectly reasonable for hap40 to last much, much longer.
 
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Curious though, if you can get stainless to stay sharp it would suggest that it is properly deburred. And carbon is so much easier to debur compared to stainless, it would seem that OP knows how to debur.
Not trying to contradict anyone, just acknowledging OP's question and wondering what other factors may be at play.
 
Boynutman said:
Curious though, if you can get stainless to stay sharp it would suggest that it is properly deburred. And carbon is so much easier to debur compared to stainless, it would seem that OP knows how to debur.
Not trying to contradict anyone, just acknowledging OP's question and wondering what other factors may be at play.
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It's a fair point. I was just thinking that I've heard HAP40 takes a very thin and brittle burr so my thought was it was disappearing quickly.

Lots of factors beyond steel could be at play here though so it is all just wild speculation.
 
Technically hap40 is not stainless.

If both are properly deburred and sharpened you would expect hap40 edge to last a lot longer than low alloy carbon.

Since carbon knives in question get touched up and sharpened much more often there is a lot more chance to leave some burr or round the edge.
 
Boynutman said:
Curious though, if you can get stainless to stay sharp it would suggest that it is properly deburred. And carbon is so much easier to debur compared to stainless, it would seem that OP knows how to debur.
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A fair point. The reason I asked about deburring was OP's charged leather stropping to revive an edge. That made be suspicious.
 
HumbleHomeCook said:
Well, now that's not entirely accurate. There are semi and full stainless steels that have outstanding edge retention. The fact is, edge retention depends on a lot more than the steel.
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Sorry, poor wording on my part. What I meant was that stainless/semi-stainless steel (especially R2/SG2 and HAP40) has greater edge retention than carbon steel.
 
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Maybe PM steels would be more accurate since ZDP-189 is supposed to surpass HAP40 for edge retention.
 
Thanks for respones guys and good advice. I will focus on deburring more (light strokes on Aoto at the end and leather with paste). I dont give up. I really want to try honyaki someday

My gyuto Hap40 is from Sukenari. Sharpen at 12 per side. Toyama 15 per side.

Also have suji and petty from Sukenari line.
 
Perzua said:
Why ?
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After stropping and deburring on your finest stone it doesn't bring in the best case much improvement, while if not done very cautiously, which is far from simple, may cause a lot of new problems, like weakening a good edge, rounding it, create a new burr. So, it's a factor I would eliminate at first.
 
I don’t sharpen at high grit stones unless the steel is very very thin and hard, otherwise higher grid stones makes my knives went dull faster, I usually sharpen around 1k-3k grit.
 
Jason183 said:
I don’t sharpen at high grit stones unless the steel is very very thin and hard, otherwise higher grid stones makes my knives went dull faster, I usually sharpen around 1k-3k grit.
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There’s little reason to go beyond 3k with double-bevelled ones used in Western cuisine. Very often I use fine stones only for stropping and deburring, and the finest one for deburring only, and, later on, for touching up.
 
So guys, what would be a best scenerio for me ?

1. 1000 and few light strokes -> Aoto and few light strokes. The end or leather ?
1. 1000 without deburring -> Aoto and few light strokes. The end or leather ?
1. 1000 -> Aoto -> 6000 only for deburring
 
Are we ruling out bad HT as a possibility?

No way even a regular 56 HRC wusthof has such bad retention and dulls after 8kg of produce.

Because it seems like OP is doing everything right.
 
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