# JKI 1K and 6K diamond stones



## Barmoley (Feb 20, 2020)

I've been curious about JKI Diamonds for a while now. I like to play with different steels and some of these are very wear resistant. Steels like CPM-10V, k390, m390, s90V, maxamet, CPM-4V, vanadis23, T1, etc are somewhat difficult to sharpen on regular water stones. They seem to sharpen some, but specifically maxamet and 10V class don't seem to work well with regular water stones. Some believe that for steels that have a lot of vanadium and other hard carbides, regular abrasives are not enough because these hard carbides are actually harder or at the same hardness as the abrasive in the regular, synthetic water stones. Because of this the abrasive doesn't actually cut the carbides and only wears down the matrix, leaving a less than optimal edge. I don't know if this is what happens exactly, it makes sense to me, but that doesn't mean it is true. In any case sharpening these steels on regular stones hasn't been easy for me. To solve this problem I have DMT diamond plates which work reasonably well in getting these steels sharp, but the process is not pleasurable at all. Now, I don't consider sharpening a fun activity as of itself like some people here do. Sharpening is not a hobby of mine, it is a necessary evil that comes with my hobby of playing with different knives and steels. As such I want to do it well, efficiently and as fast as possible, I don't much care how exactly a steel feels on the stones. It is not that I can't tell the difference I just don't care enough. For me, how a steel feels on the stones is not even a consideration when buying or selling a knife, it doesn't come into my decision making process at all. Given all of the above, I really dislike the feel of sharpening on DMT diamond plates. Both feel and sound are very unpleasant, not enough for me not to do it, but enough that I really don't want to. I am explaining all this so that some of what I say later about JKI diamond stone is taken with my feelings on sharpening in mind.

So I have a problem I have Gesshin synthetic stones that are great on "normal" steels, but are less than optimal on wear resistant steel and I have diamond plates that work well, but are annoying to use. A perfect solution then would be to combine the two, sounds reasonable to me and this is where JKI diamond stones come in. I've been agonizing over buying these for a long time, they are somewhat expensive and I have the tools that work. I also didn't know if they would feel better enough to make a difference. Fortunately, @daveb was kind enough to let me borrow his set. 

I tried both 1K and 6K diamond stones and I am very impressed. I tried the stones on regular steels and also on CPM-10V @63 HRC. The stones work on everything. They cut fast, not necessarily faster than regular Gesshin stones of the same grit on regular steels, but much faster on hard to sharpen steels. JKI diamonds leave very uniform finish, both 1K and 6K leave very uniform and consistent edge. The rest of my Gesshin stones are all soakers and I am ok with that, but it is still very nice that these diamond stones are splash and go, and they truly are. This makes them very convenient to use since instead of going to the garage where I permasoak my other Gesshins, I can just keep them in a drawer in the kitchen, not a big deal but nice. I really like the edge that these stones leave. The 6K leaves an edge that is refined, but still has bite. To me there is more bite from diamond 6K as compared to regular Gesshin 6K and is closer to Gesshin 4K even though the edge refinement is closer to Gesshin 6K. It is hard to describe, but I really like it. I think I've gotten the best edge from diamond 6K on 1.2519 steel than I've ever gotten from any other stone, the edge is amazingly sharp and yet cuts tomatoes extremely well. Usually, I don't go above 4K for tomatoes, but with diamond 6K it works perfectly. To me this combo of 1K and 6K can pretty much be the only stones used for regular sharpening. Thinning and fixing major damage is different and will require coarser stones, but for regular sharpening of kitchen knives these 2 could probably replace the rest of the stones I have. I should've probably bought these from the very beginning and be done with it.

I left the feel of the stones when sharpening to the end because of what I said in the beginning, I don't care enough to worry about the difference of how 1095 vs 52100 feels on the stones, yet I hate DMT diamond plates. JKI diamond stones feel great to me. They don't feel as good as regular Gesshin stones, those feel amazing, and yet the diamonds feel very good. They are hard and so they feel hard not as creamy as Gesshin soakers, but they feel and sound infinitely better than diamond plates, so much so that the comparison shouldn't even be made.

In conclusion, I liked the stones very much. They work on all steels I tried, 1.2519, 1.2562, Gokinko, CPM-10V, and 52100. The stones are true splash and go, they don't seem to dish at all, they leave a very consistent and uniform edge. 6K diamond might be the perfect finisher for my kitchen use. The stones feel very close to other synthetic water stones and should not be compared to diamond plates at all, absolutely nothing in common. Big thank you to Dave for letting me borrow the stones, I regret to inform you that I misplaced them somewhere and I don't think I can return them


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## JBroida (Feb 20, 2020)

Glad you’re happy with how they work


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## daveb (Feb 20, 2020)

Hehehe. Thought you might like them. For many of the same reasons I do. And they do work best of any stones I own on friends / family knives - from Wustie to Shun.


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## panda (Feb 22, 2020)

i just bought these having tried them before a few years back. used them today and boy they are even better than i remember it! it's so freaking fast and the 6k has really good feedback.


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## Barmoley (Feb 23, 2020)

The edge 6k leaves is very impressive too.


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## TSF415 (Feb 23, 2020)

Great write up. And now apparently I have to work these into my budget


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## refcast (Feb 23, 2020)

yeah the stones are pretty fun. because they are so hard they just ink out swarf. super duper tooth. Really great for consistent angles. I agree not necessarily faster than gesshin synthetics, but they cut pretty consistently with each steel. . . a less variation than with the gesshin synthetics.


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## nakneker (Feb 23, 2020)

I have DMT diamond plates, bought them specifically to handle S90V and some other steels. Like the review, I don’t enjoy them much, they work but bring little joy.

I think I’m going to try these, they sound like they have huge potential for S30V, S90V, S110V, m390 and the such. I own the JKI vitrified 800 diamond stone. It lived up to the hype, it gets used more than any other stone I have actually. Sounds like these will too, I’ll try them on the kitchen knives too but they sound like the ticket for some stubborn EDCs.

Thanks for the review, very helpful and appreciated.


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## Keith Sinclair (Sep 24, 2020)

I've had the 1K for a while. Keep it on work bench with 140 & 400 Atoma plates. Comes with own base, Still works well


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