Sharpening Asymmetric Grinds

Discussion in 'Maintenance, Tinkering & Embellishment' started by Eli Chaps, Oct 24, 2020.

  1. Eli Chaps

    Eli Chaps Gold Member Gold Member Basic Member

    Apr 20, 2018
    I'm looking at some Japanese knives that have 70/30 and 60/40 grinds.

    Now, I will be getting some water stones, but I gotta say I'm little freaked out about sharpening an asymmetric grind. I work so hard to maintain a constant angle and then on a single knife you have to alter it from side to side.

    Am I just over thinking it? Anything tips?
     
  2. Ourorboros

    Ourorboros

    568
    Jan 23, 2017
    Some people just accept the fact that they will change the grind over time.
    For me it's about feeling where the bevel is and staying there rather than the angles my hands naturally go to. I have to do that anyways because some of my knives are at decidedly steeper angles than others. Trust the feel, it's in your hands and you know what wrong feels like.
    Otherwise it's back to basics if you're not sure - the old marker, if you want to keep the angles.
    In this regard a softer stone helps, since you will plough into the stone with your edge leading stroke if you take too high of an angle.

    I'm going to be interested in your water stone journey - that is it's own rabbit hole.
     
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  3. Eli Chaps

    Eli Chaps Gold Member Gold Member Basic Member

    Apr 20, 2018
    Yeah, that' what I figured. Like you, I do tend to find the angle for each knife so I reckon in that sense it's the same thing. I'll just have to be very conscious of making that adjustment for each side all the way through stropping.
     
  4. jpm2

    jpm2

    Nov 19, 2014
    You could always build something like @tiguy7 has here.
    [​IMG]

    With turnbuckles, you can adjust each side independently.

    Been meaning to make one of these for a long time...
     
  5. garry3

    garry3

    Sep 11, 2012
    It would be about the only time I might use a sharpie. Just match what is there already.

    Truth is I have experimented with it on a gyuto and I can't tell the difference from a 50-50, so that is how I do it, 50-50 for now. Perhaps if my knife skills were better or I was cutting thicker stuff or something...
     
  6. tiguy7

    tiguy7 Gold Member Gold Member

    Jun 25, 2008
    When I sharpen chisel ground edges, usually at 15* on one side and 0* on the other, I periodically wipe the burr on the non-bevel side back into the grinding plane on the side of a ceramic blade (edge trailing). Ceramic blades are very smooth and hard.
     
  7. Ourorboros

    Ourorboros

    568
    Jan 23, 2017
    I think stropping is where you need to be more careful than a stone.
    Is this your Yaxell, or do you have a new gyuto?
     
  8. Craig James

    Craig James

    185
    Oct 30, 2018
    Wow Eli, you're actually taking the plunge and moving away from your much loved oil stones?? Good luck :)

    Although I don’t own any asymmetrical knives my understanding was that asymmetrical bevels does not necessarily equal differing angles on either side. One side is simply ground more than the other.

    I think here you give it your best shot without getting overly caught up on the detail and just do your best to match the existing bevels

    I watched this video on the subject a while back

     
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  9. HeavyHanded

    HeavyHanded

    Jun 4, 2010
    The waterstone journey is going to be a lot more involved than sharpening your asymmetrical grind. Just go slow and use a Sharpie.
     
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  10. Eli Chaps

    Eli Chaps Gold Member Gold Member Basic Member

    Apr 20, 2018
    The Yaxell is 50/50 and I work it on my oil stones and Arkansas. Even with the BD1N at a reported 63Rc it is still pretty easy to sharpen.

    I'm going to be looking to get a couple new knives. A petty and honesuki are on the short list. Still want stainless and don't want to break the bank so eyeing Kanehide PS.
     
    Last edited: Oct 26, 2020
  11. Eli Chaps

    Eli Chaps Gold Member Gold Member Basic Member

    Apr 20, 2018
    Oh, the oil stones will stay but it's getting about time I give those water stones a try. :)

    I don't mind saying I'm a little intimidated by it all. I'll be back bugging you all for input on those too. Still researching but the Shapton Glass seem like a popular option.
     
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  12. garry3

    garry3

    Sep 11, 2012
    Arks will wreck an edge a lot faster than they can fix one. They are so unforgiving that anyone that is proficient in their use will pretty well hit the ground running with softer, faster, more forgiving stones.
     
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  13. HeavyHanded

    HeavyHanded

    Jun 4, 2010
    I haven't used them but they get good reviews. There's a lot of good stones out there...my personal favorite are Suzuki Ya and the old reliable Nortons (just wish they weren't so expensive).
     
  14. Eli Chaps

    Eli Chaps Gold Member Gold Member Basic Member

    Apr 20, 2018
    For less mess I was thinking splash and go. Any thoughts?
     
  15. Ourorboros

    Ourorboros

    568
    Jan 23, 2017
    Shapton Glass are excellent stones. The hardest water stones in terms of 'give'. Most water stones use aluminum oxide as the actual abrasive.
    The 500 and 2K form the basis of my lineup. The finest ones have a tendency to glaze. Their specialty are non/low vanadium steels with an HRC of 63 or more, but they certainly aren't limited to hard steels.
    They wear slow, so you don't have to worry about flatness in a session. But of course if you let them go flattening will take a while. Also they benefit from lapping just to keep them aggressive. They have a lot of abrasive but because of the hard surface they don't release new abrasive easily.

    I settled on a sink bridge to reduce the mess, even with splash and go I still got swarf on the counter.
    But splash and go is really convenient. Soakers have different soaking times and that gets in the way of just getting things done.
    However the feel of soakers vs splash and go are different. A Suehiro Debado has a softer feel that is more pleasant. Soakers also release abrasive more readily.

    What makes this such a rabbit hole is the balance of qualities in stones. That's why I believe above a certain quality of stone it's more a question of what you like that which is 'better' along one aspect of performance.
     
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  16. HeavyHanded

    HeavyHanded

    Jun 4, 2010

    The only true splash and go stones I own are my polishing stones above 6k - none of them need to soak. I used to own a set of Shapton Pros but sold them - they were not as nice as any of my better stones IMHO, either in terms of speed or grind quality. The Suzuki Ya don't need to soak but I leave them in a bath full time. They are very hard ceramic stones (except the 2k) that make just a hint of mud in use and dish very slowly.

    The Nortons are hands down the best stones I have for common carbon and budget stainless. Once you start getting into alloy tool steels and the higher Rockwell carbon steels they begin to stutter, but on steels that are liable to form stubborn burrs they do a great job.

    There are so many to chose from...many of which I have never used...
     
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  17. Eli Chaps

    Eli Chaps Gold Member Gold Member Basic Member

    Apr 20, 2018
  18. Craig James

    Craig James

    185
    Oct 30, 2018
    Gotta say I adore my Chosera’s/Naniwa Pros...
     
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  19. Jason B.

    Jason B. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 13, 2007
    Asymmetric grinds are more than edge bevels... Its the whole knife and it is ground with asymmetry in mind.

    Starting with the blade, it is angular ground on the presentation side and flat ground on the backside. This makes it so you MUST sharpen it properly or you ruin the geometry because the blade itself is asymmetric.

    The edge is most commonly referred to as the 70/30, some call it 60/40 or 90/10 but if we are talking about Japanese knives its 70/30. Of the hundreds if not thousands I have sharpened its always a 70/30 ratio... If you are doing it right.

    Doing it right always seems to be the problem, many seem to forget that the center line of the blade is still where you want the apex of the edge to end up. The edge angle should also not change... Its a 70/30 ratio, not an angle. The bigger issue is bad instructors telling everyone that ALL knives should be sharpened this way, which leads to inexperienced sharpeners making all their knives single bevel knives. This is especially bad for clad knives and I'll let you guess why.

    For stone, I am almost always recommending the Shapton Glass and they would do fine here especially in the coarse grits but for a 1k and up I much prefer softer stones on J-knives. On softer stainless blends to include VG-10 the Chosera 400 and Naniwa 2k Aotoshi is a touch combo to beat. The Chosera 400 is literally one of the fastest cutting Japanese waterstones but yields a scratch pattern more like an 800-1000 grit stones. The 2k "Green Brick" as it is called is very aggressive at removing metal from the start but quickly starts to polish and finishes near a 4k level. The edge has more bite but a more polished sharpness and excellent for kitchen work. The Arashiyama 1k and 6k are also very good, my first stone set actually, and probably near ideal for most kitchen knives. I also really like the Suehiro Cerax 1k and 6k, muddy stones but very fast and produce a very good edge on a wide range of steels.
     
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  20. Eli Chaps

    Eli Chaps Gold Member Gold Member Basic Member

    Apr 20, 2018
    Thank you very much Jason. I was doing a fair bit of reading/watching on this last night and learned just what you are saying about the knife grind, steering, etc. Some even discussed the primary blade grind being essentially convex. Lots of cautions about not going 50/50 and improper sharpening. Didn't help my confidence level. :D

    I'm starting to think that maybe I should go at this in a little different order...

    1) Get water stones and start leaning how they work and adjusting my method accordingly.
    2) Stick to 50/50 Japanese knives and learn how to sharpen those steels and dealing with cladding.
    3) Re-consider trying asymmetric grinds.
     

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