Takamura ootb edge fragility

I have been wondering about this and noticed there wasn't a discussion on it that I could find, so I thought I'd bring it up here.

One of my favorite knives has been a Takamura 210mm gyuto. The extra thin blade is just right for many tasks I do, and the profile is excellent in my opinion. However, on both the 210mm and the 180mm I have (from different vendors), the out of the box edges were pretty weak. It was sharp, but the first cutting session with it left several small chips and an area of rolled edge. Having both problems was a bit unexpected, as the online praise for the knives mentions no such problem.

Sharpening the edges with a fresh bevel has, for me, addressed the problem. This leads me to thinking the out of the box edge is fatigued. Another member bought a Takamura based partly on my recommendation and apparently encountered the same fragility. Any wisdom out there on the issue?

 

Another member is me and I received my Takamura 180mm gyuto just two days ago. As XooMG said, OOTB edge looks pretty sharp and could slice paper easily. More then enough for kitchen. However it was only today when I actually cut some food with it. I'm not able to make a proper macro shots of edge, but here's my best try (click to view full size):




This is how edge looked after cutting crusty baguette, apple and banana. Ok, I admit, that baguette was pretty hard and you may consider this edge to be a result of user error, however, I had just about the same situation with on of my Watanabe knives. Same micro-chipping on the OOTB edge that has gone away since I put a new edge. So I'd like to stress that this happened to me twice, with knives from different makers. And I couldn't reproduce it after putting new edge.

 

Good old factory buffering? Or HT after grinding?

 

I guess it's possible the edge itself was ground at high speed and generated excessive heat, but with the thinness of the knife, I'd expect high heat to have deeper consequences. 5 minutes or so on a JNS 800 seemed to get me to much more stable steel.

If it were hardened with too thin an edge relative to the body, chipping would make sense, but the edge rolling in various places doesn't seem consistent with that. When getting to work on it with the JNS800, the burr flipped almost instantly and was very large. It felt like the edge had been flexed back and forth a lot like bending and rebending a paper clip...easy to bend, and ready to snap off. My feeling was that whoever was sharpening it originally was putting enormous pressure on it.

Thanks Anton for the pics. Mine wasn't chipped in as many places, but I only cut a few carrots.

 

wire edge?

 

I am not surprised and would not be worried in this situation. I have had conversations with a few knife enthusiast that sharpen every new knife they get right OOTB just for this reason. For them ALL factory edges are way to dull or very weak.

 

Thanks for the comments. I figure this is something that comes up with more than a few makers, but it's sometimes shocking to see a nice new knife chipping on carrots and bread and rolling the edge on the board. Especially when the knife is promoted in some places as having a great edge out of the box, caveats like this might apply.

Sharpening it gave me a good opportunity to repair the tip too.


Forgive the bevel unevenness in the second pic; it's actually pretty even but my angle of reflection and wide-angle perspective exaggerate it a bit.

 

When edges are sharpened on powered machines (or a lot of pressure on the stones), it tends to generate a large burr, regardless of heat. Each pass you make, the edge rolls over and fatigues and leaves a weaker edge than can be sharp, but is weaker because of the back and forth passes, regardless of knife or heat treat. I sharpened some thick cleavers for a friend and used my belt sander at a very low speed. The edge did the same thing until I stropped it hard or took it to a stone which got rid of the burr/fatigued metal. Same thing has happened on knives that I thinned/reground with a belt sander. Even w/o introducing heat into the edge, the metal is still fatigued from the belt sander process and the edge rolling back and forth. Taking it to the stones removed that weak metal and left a much nicer/more durable edge.

 

Cheers, glad to get some more confirmation. I don't normally deal with fresh factory edges but the Takamura's was praised so I thought I'd give it a shot. Had never before encountered edge fatigue on anything bigger than a slight burr. Wasn't too big a deal to rebevel with a JNS800 but I wonder how a stone-shy novice might react.

 

Propably thinned about close to a hundred knives on a belt grinder but never sharpened with it, so Im not sure how does it affect the steel,
What I know is, and especially with poor quality stainless steel, the double shartpening makes wonders.

Youall remember how some years ago Dave mentioned it, that double sharpening gave him some best results, I actually noticed it helps with the cheaper poorer knives.
With carbon, but also some semis, like the Yoshikane, I found it might be counterproductive.

So the novice should not panic, just take the knife to the stones first and open the blade up and be happy.
As to the OOTB edge, when the knife is not a handmade object - its just bollocks and lets be honest. There is no such thing.