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Kohetsu HAP40 questions.

Tue Mar 18, 2014 6:19 pm

hey there, i have a question re the HAP40 Kohetsu... I am interested, but a salesperson at a knife shop here in Seattle mentioned i should be careful about the knife blade easily chipping because of its hardness (I'm NOT planning on hacking bones with it, heheh). Also, that HAP40 is not a true stainless so it will eventually discolor or rust on the knife edge. your thoughts? Sorry if i'm inappropriate with my questions, I'm really a newbie at this and know little about metallurgy. I just want super good knives that will perform better than my Wustoff Tridents. btw, thanks for your videos, they are very informative!


Re: Kohetsu HAP40 questions.

Tue Mar 18, 2014 6:26 pm

My wife and I used the prototype a lot last year and the knife did have some small micro chipping on the edge (after several months of home use) and it also did stain a little only on the edge. The flip side was the edge held better than just about anything I've ever tried and I've tried a couple knives in my 12 years running this store. My wife nick named this knife the voodoo knife and that's high praise.

Re: Kohetsu HAP40 questions.

Tue Mar 18, 2014 6:33 pm

I wouldn't worry about the non-stainless nature of the steel. Even quite reactive carbons are easy to care for, particularly for a home cook.

I haven't tried the HAP40 myself but you can reduce the probability of chipping by keeping the knife quite sharp, not trying to chop through bone etc. and the use of a proper cutting board.

Re: Kohetsu HAP40 questions.

Tue Mar 18, 2014 9:23 pm

How does the 210 rock cut? I've moved to pull, push cutting and chopping these days but still like a knife that rock cuts well.

Re: Kohetsu HAP40 questions.

Tue Mar 18, 2014 11:32 pm

Paul - Yes, HAP40 is going to be a little more prone to chipping than softer steels. If you use the knife properly, stay away from hard ingredients(i.e. partially frozen food) and bones(even scrapping alongside a bone is a bad idea) you should be able to prevent chipping in a home environment. No using it to pry, opening boxes with it, or as a screw driver either! ;)

Now, micro-chipping(different than chipping) on the other hand is inevitable with higher hardness steels. When steel reaches it's failure point through usage either it breaks(micro-chips) or bends(rolls an edge). The higher the hardness the less likely steel is to bend and more likely it is to break. The inverse is true of softer steels. Whether Microchips are a big deal to you and worth it for the increased edge retention is highly personal preference.

If this is your first foray into J-knives I would highly encourage you to pick a knife based on a myriad of things other than steel(weight, blade height, handle, etc.). All knives will get dull eventually.
HAP40 may be perfect you, but there are a number of fantastic knives in that price range that might be a better fit for you(Kono, AS laser, TKC).

If you are set on HAP40 I would pull the trigger sooner rather than later, they are not going to last long. If you would like to explore other options let us know. We love knife talk :)

Re: Kohetsu HAP40 questions.

Wed Mar 19, 2014 2:35 pm

How does this compare to the Kohetsu AS or Takamura 210 in R2?

Re: Kohetsu HAP40 questions.

Wed Mar 19, 2014 3:05 pm

I just ordered the Nakiri, since I don't have a good one and this seems like a great steel to try out.

Asking the gurus here, do you think putting a micro bevel on the edge would help prevent the micro chipping?

Probably not going to be an issue for me anyway, i have so many knives here I doubt this new Nakiri will get enough use to cause a problem

Re: Kohetsu HAP40 questions.

Wed Mar 19, 2014 3:36 pm

Any information about the abrasion resistance of this steel? Can it be sharpened with normal stones?

Re: Kohetsu HAP40 questions.

Wed Mar 19, 2014 5:34 pm

I haven't used HAP40 myself, but if I recall correctly Franz69 mentioned, in an earlier discussion about this steel, that it has similar abrasion resistance to sharpening as M390.

Re: Kohetsu HAP40 questions.

Wed Mar 19, 2014 5:54 pm

Shapton Pros work just fine. If you're going to to crazy with high grits you will want to use diamond above ~5K so as to be able to shape the Vanadium and Cobalt carbides and not just abrade away the matrix.
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