newb question: hard jnat's vs. kitchen knives

Discussion in 'Sharpening Station' started by catalystman80, Aug 6, 2018.

  1. Aug 6, 2018 #1

    catalystman80

    catalystman80

    catalystman80

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    Hi folks,

    Thinking about getting into the JNAT game and in my internet "learning" for the past couple of days, one thing I observed is that hard stones (> LV4, that's another thing I need to learn, seems like people use different scales/standards for hardness) are generally not recommended for kitchen knives because it's difficult to sharpen on hard stones.

    Could you please advise why this is the case? Couple of things I did find out are (and please correct me if they are wrong):
    - it's difficult to raise slurry on harder stones (could this be mitigated by using a tomo nagura, and if tomo nagura for a given stone cannot be found, what are some alternatives?)
    - harder stones tend to scratch the knives despite its ability to polish higher than softer stones (what if I were just using it for a secondary or microbevel sharpening? would this work?)

    One other thought is that coming from having used harder synthetics (shapton pros, choseras), I sometimes prefer both an edge trailing and leading strokes as I've found the edge leading stroke doesn't dig into the harder stones (though I've gotten better with my pressure control, so I'm okay on softer synthetics too). I'm wondering whether this type of method could be transferable to hard JNATs, or am I completely off the rail here?

    Just to provide some context, just a home cook/enthusiast with gyutos in your typical clad blue's and white's, some ginsankos, HAP 40, and ZDP 189. Mainly started thinking about JNATs to get that kasumi finish that my Shaptons/Choseras won't give me without sacrificing the edge performance. Initially thinking adding one or two JNATS to follow a 3k or 6k synthetic depending on the knife/use.

    Thanks for reading through my ramblings, would greatly appreciate any wisdom/experience/feedback you'd be willing to share. Thank you!

    Josh
     
    Last edited: Aug 7, 2018
  2. Aug 6, 2018 #2

    valgard

    valgard

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    I have no issues with hard Jnats and generally prefer them. That being said, It’s generally more difficult to get an even finish with a hard stone than a soft one and that’s why typically you see softer stones recommended for beginners. Some very hard stones are plain unusable for cladding and almost exclusively useful for a crisp micro bevel or ura but those are the more extreme cases.
    I do edge leading strokes to finish the edges but only with light pressure. More like gentle cutting the water motions.

    All in all, to get you started I would get at least 1 soft-ish stone. Hard stones can leave awesome finish but you better have a softer one at hand for that very convex bevel or shallow low spot .
     
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  3. Aug 6, 2018 #3

    valgard

    valgard

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    also, generally speaking hard jnats are much harder than hard synthetic stones.
     
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  4. Aug 7, 2018 #4

    catalystman80

    catalystman80

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    @valgard thank you very much! so it is possible to at minimum finish the edge on a harder stone (but point taken that it's much harder than a hard synthetic stone). Yes, I do plan on getting one soft one for sure.
     
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  5. Aug 7, 2018 #5

    vinster

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    Many people don't care for an edge as refined as a hard jnat can put on kitchen knives (most of the time). It's generally harder to get a slurry going from a hard jnat vs a hard synth stone.

    But if you want to do it a tomo nagura is a good way to go. I personally like to abrade the surface of harder stones with an atoma 1200. I don't always make a slurry before using hard stones, but I find that having the stone surface "prepped" with the atoma helps it to sing.
     
  6. Aug 7, 2018 #6

    catalystman80

    catalystman80

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    That’s a great point, I actually hardly ever go past 6000 (most of the time 3000) on my gyutos, but I do like to take my yanagiba as high as possible. Thanks for the tip on Atoma 1200 as an alternative to a Nagura (albeit not to necessarily make slurry as you noted).
     
    Last edited: Aug 7, 2018
  7. Aug 7, 2018 #7

    valgard

    valgard

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    can’t agree more with refreshing the surface of some stones
     
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  8. Aug 8, 2018 #8

    Marcelo Amaral

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    Regarding only the sharpening, polishing matters appart, a harder stone is less forgiving and it asks for a better angle control while sharpening. As a general rule, hard jnats tend to be finer, leaving a more polished/refined edge. Therefore, it makes more sense to use them on high quality blades that can keep that edge.
     
  9. Aug 9, 2018 #9

    catalystman80

    catalystman80

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    Thank you for your input! The part that I would like to understand more clearly is why a harder stone is less forgiving. When I was learning to sharpen on synthetics, my experience was it took me longer to sharpen on softer stones because if you are not careful, you can plow into the stone thereby ruining the edge you established. So I had to adjust by learning how to control and lighten my pressure better, and to use more of edge trailing sharpening.

    Angle control is always paramount in my opinion, so what is differently about hard naturals vs hard synthetics that make it less forgiving? I realize hard natural is much harder, so would inconsistent angle control lead to poor/inconsistent establishment of the edge or possibly even chipping? (Kinda like when someone tries to hone a Japanese knife on a steel meant for softer steels).

    Thanks!

     
  10. Aug 9, 2018 #10

    catalystman80

    catalystman80

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    I do have an Aiiwatani on the way, so I’ll start learning from getting some dirt time as well :)
     
  11. Aug 9, 2018 #11

    Badgertooth

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    Generally a harder stones cuts less quickly so if your angle is even slightly off, you aren’t maintaining an apex, you’re crushing an apex. A faster cutting, softer stone will, at a slightly incorrect angle, more quickly reastablish an apex and not crumble or roll it as quickly.
     
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  12. Aug 9, 2018 #12

    valgard

    valgard

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    another thing to note is that soft and hard have very different standards for synthetic and natural stones in my experience so your problem of digging into soft synthetics is less likely (not completely unlikely) to happen with Jnats I think.
    Also, a bit a friability + the speed helps shaping that apex like Otto said and it "hugs" the edge a bit and creates a slight convexity at the edge, with a hard Jnat you are basically cutting a plane, if you can't keep that angle perfect the next plane will wreck the previous one and so on.
     
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  13. Aug 9, 2018 #13

    Badgertooth

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  14. Aug 9, 2018 #14

    catalystman80

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    Gotcha, thanks a lot guys! I’m connecting the dots now. Sounds fun to try, challenge accepted! Well, when I get a harder stone eventually.
     
  15. Aug 10, 2018 #15

    madelinez

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    One thing I've noticed with the couple of naturals I own is that they don't work great on steels like ZDP-189 and HAP-40. It probably depends what the actual abrasive material in the stone is made from, but just worth considering.
     
  16. Aug 10, 2018 #16

    catalystman80

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    Thanks for the input, I figured as much and assumed the naturals will work mostly with the more traditional hitachi steels, but good to know. I’ve actually been loving using Naniwa diamond stones on the two steels, so they are well taken care of :)
     
    Last edited: Aug 10, 2018
  17. Aug 17, 2018 at 6:41 AM #17

    catalystman80

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    So bought myself an Aiiwatani LV 3.5 and Ohira Suita LV 2.5~3, along with few others that's been lent to my by a very helpful, new friend from the forum.

    Perhaps I'll write something lengthier in hope of helping other newbies like me, but some initial impressions:

    - The feedback is amazing, even the hardest stone I have tells me through both tactile and audible feedback whether I'm on or off.
    - I never knew they are really splash and go! I'd imagine there may be other JNATs that are thirsty, but the finishing stones I've used so far use sooooooo much less water than my synthetics. Cleaning up the counter is so much easier now!
    - Each stone has a unique smell to it; mostly pleasant.
    - I may need to do further testing, but I almost don't feel the need to strop afterwards to remove any remaining burrs. After some lighter edge trailing strokes on the stone, and then maybe running the edge lightly on my cutting board, I'm very satisfied with the sharpness.
    - The surface on all the stones came in excellent condition, but wondering about whether I should get an Atoma 1200 which seems to be the popular choice for "conditioning" the surface (I already have Atoma 400, and a full range of DMT 8" Diaflats, but not sure the Diaflats are recommended, haven't seen anyone talking about using them for this purpose). I would also like the option of getting the surface as smooth as possible....would a set of Asano Naguras work? Or is there a cheaper but just as effective method?

    I'm sure there are couple others I'm forgetting to note as my initial impression, but long story short, I'm very much enjoying the experience (albeit with a downside of a lot thinner wallet :D)
     
  18. Aug 20, 2018 at 4:57 PM #18

    vinster

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    The scratches on the surface used to drive me crazy! I've found the best way to get rid of them is to.... use the stone! hah.

    I can't say I've tried everything but an atoma 1200 will leave a visible scratch pattern. I've tried various synthetics but didn't want to worry about grit contamination. Some nagura worked better than others but depending on the stone, some scratches remained.
     

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