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A question on asymmetry

post #1 of 12
Thread Starter 
Hi all,

I've been doing a lot of reading about asymetric knives and there's one thing that's got me stumped and I can't find any info on this.

Why can't you steel an asymetric knife?

Im assuming people say this because they create asymmetry by sharpening more on one side. Steeling an edge like this would undo the asymmetry ?

However , my asymetric knives have different angles on each side but are sharpened evenly. They are also HRC 60 .

Why can't I steel these with a fine ceramic if I match the asymetric angles with the steel?

Or am I wrong for sharpening the differnt angles evenly and should i be sharpening less on one side? Thus making steeling a bad idea?

Some light shed on this would be appreciated, it's taking a while to wrap my head around it all smile.gif
post #2 of 12

I think Jon from JKI addressed the issue in a youtube video. I'll try to find the post and add the link. 

post #3 of 12

i dont remember if i've made that video or not, but if not, its on my list of things to do.

 

the top part of this blog post may also be relevant:

http://blog.japaneseknifeimports.com/2013/07/a-series-of-notes-on-various-subjects.html

post #4 of 12
Thread Starter 
Jon,

I believe I have watched all your videos on sharpening.
Thank you so much for these they were very thorough and informative.
However I don't recall a video on asymmetry.
The link you posted is slightly relevant although if the answer to my question was in there it went straight over my head.

Harlock,
Are you referring to the video on sharpening steels and honing rods?
I seem to remember the main point of that video was that steeling knives of high hardness is a bad idea as it results in chipping. My knives are HRC 60 and unless I'm ill informed this is not that hard and an acceptable hardness for steeling ( with light pressure)

My main question is why can't you steel an asymetric blade under HRC 62 ? Assuming that the angles are different, but sharpened with relatively even amount of strokes on each side . ( this is what I do, am I doing something wrong here)

As a side note the blades are both ground 70/30 right hand bias.
210mm Tadasuna wa gyuto
270mn Missono Sweden sujihiki
post #5 of 12
Quote:
Originally Posted by geo87 View Post

Jon,

I believe I have watched all your videos on sharpening.
Thank you so much for these they were very thorough and informative.
However I don't recall a video on asymmetry.
The link you posted is slightly relevant although if the answer to my question was in there it went straight over my head.

Harlock,
Are you referring to the video on sharpening steels and honing rods?
I seem to remember the main point of that video was that steeling knives of high hardness is a bad idea as it results in chipping. My knives are HRC 60 and unless I'm ill informed this is not that hard and an acceptable hardness for steeling ( with light pressure)

My main question is why can't you steel an asymetric blade under HRC 62 ? Assuming that the angles are different, but sharpened with relatively even amount of strokes on each side . ( this is what I do, am I doing something wrong here)

As a side note the blades are both ground 70/30 right hand bias.
210mm Tadasuna wa gyuto
270mn Missono Sweden sujihiki

 

Hi Geo, yeah I think that was the video you were refering to. As home cook I don't have a need for a steel and prefer to maintain my knives by stropping. Sorry can't help you here :(

post #6 of 12
I'll just give it a try. The J-knives I know come with an extremely thin bevel immediately behind the very edge, which is almost imperceptible. I'm not sure it's so much about their asymmetry, but more about the thinness. Symmetric, European knives come with clear, large bevels. So there is much more steel behind the (very) edge to support it. And of course, the Germans come with much larger included angles than the Japanese, are softer and much tougher, and will resist much better lateral forces involved with steeling.
post #7 of 12
Thread Starter 
Benuser,

Did you mean to say, I'd just give it a try?

Thank you for your explanation this is making sense.... I think.

So to summarise asymmetric japanese blades are typically very thin thus making them susceptible to damage when steeling regardless of steel hardness. the forces involved in steeling put a lot of pressure on the very edge as apposed to stropping where the forces are dispersed over a greater surface area.

Am I on the right track?
I'm just trying to truly understand the subject rather than just blindly doing it cos that's what everyone says to do smile.gif
post #8 of 12
I certainly did not mean to suggest you to give steeling J-knives a try. I meant, I try to formulate an answer. Sorry for the ambiguity.
I'm happy that my other remarks did not raise such misunderstandings.
I would add that normally steeling isn't necessary with hard thin edges. You get excellent results by stropping on any medium, charged leather, newspaper, balsa, cardboard, dry stones, jeans, you name it.
Steeling is great for truing an edge with soft blades. But it has always its price. It fatigues the steel, and with the next sharpening session the fatigued steel will have to get removed. An extreme example: a soft French had been steeled for years. I really had to remove a lot of steel before the buttery feeling was gone and fresh steel appeared that was capable of taking any edge.
I do understand that in a pro environment a fine ceramic rod is being used as an emergency solution. Even then, please have a very, very light touch.
post #9 of 12
Thread Starter 
Thanks for your help this all makes sence.
I have two sabatier nongents as well as the j knives so I'm looking foward to putting all the theory into practice. Also a HA stropping kit arriving shortly smile.gif
post #10 of 12
Quote:
Originally Posted by geo87 View Post

Thanks for your help this all makes sence.
I have two sabatier nongents as well as the j knives so I'm looking foward to putting all the theory into practice. Also a HA stropping kit arriving shortly smile.gif

 

Sweet! May I ask whats in the kit?

post #11 of 12
Thread Starter 
Balsa strop, leather strop , felt deburring block , 1u boron carbide.
As far as I'm aware the boron is good for refining edges whilst retaining the toothyness needed for most tasks. And the bare leather strop for daily mantainance/ touch ups. The edges ill be using it on range from 1k , 3k & 5k .
post #12 of 12

Nice, I cut up a bunch of balsa wood and made strops out of them (I use HA diamond sprays 0.25 to 1 micron on them). Its excessive but the stropped edges are fun while they last!

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