M390 - sharpening recommendations and/or progressions?

Discussion in 'Sharpening Station' started by thebradleycrew, Nov 14, 2019.

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  1. Nov 18, 2019 #31

    inferno

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    you could also look into one of these small dmt folding diamond ones. its would probably work ok for that blade.
     
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  2. Nov 18, 2019 #32

    k7598

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    For me the DMDs work slightly better than the Shapton Pros.
     
  3. Nov 19, 2019 #33

    kayman67

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    Actually, you can, but on a Glass would be just very poor doing.
    I make new bevels for these on stones alone.
     
  4. Nov 20, 2019 #34

    MrHiggins

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    I own an m390 EDC (Bradford Guardian 4). It's an absolute ***** to sharpen. I use a DMT fine bench stone, then a nubetama platinum 3k. Works alright, but I'd rather sharpen any other steel than m390 (I hate sharpening m4 Spyderco PM3 as well). If I were to do it over again, all my EDCs would be 52100 or A2. 20191119_204051.jpeg
     
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  5. Nov 20, 2019 #35

    vicv

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    First I just wanted to point out the sigma select II 1200 is more in line with their regular series it isn't really a select II. Awesome stone I've heard though and very hard. If this is a pocket knife I'd just use my crystolon fine to sharpen it. It will have no problem with that steel or any steel and you can get a very good edge with it with some practice
     
  6. Nov 20, 2019 #36

    lucabrasi

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    Generally steels with 4 percent vanadium and less are doable with regular sharpening stones. Above that and the vanadium carbides make it pretty miserable without diamonds.

    I’m just parroting what I’ve heard, none of my own science there. But...in practice it has seemed true.

    M390 is right on that line, but with both cerax and shapton I’ve had some good results.
     
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  7. Nov 22, 2019 #37

    Keith Sinclair

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    If you start with a lower bevel on M390 say around 3 to 5 degree use a course stone or diamond plate like a 400 Atoma. Finish higher bevel use a med. Stone to get an even Burr. If you want to refine edge less finger pressure polishing stone.

    My only experience with M390 is full size spyderco but I use it a lot for yardwork living in back of valley like a rain forest at times. I had to thin it some to cut better even on a small blade was a bit of work. After that easier to sharpen relatively. Can put a sharp edge on it and it's toughness works well for the abuse I give it.

    In a pro kitchen where ease of be sharpening is important for quick touch ups there is a reason why a lot more R2, & other user friendly powder steels are popular for good reason.

    Also my sharpening on spyderco works for me but not a gyuto. Still I know but you could wear down a stone thinning.
     
  8. Nov 22, 2019 #38

    inferno

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    it startes even faster than that imo. 4%v with about 1%C nightmare starts. but with higher carbon the boring/slow stuff starts already at 2% imo.

    d2 is less than 1% V but 1,55C and already that starts to get quite slow on low grade stones. not likea 4v steel though. but still noticable.

    a 4%V steel like s30v is almost impossible to sharpen on a device like the sharpmaker. it will take hours.
     
  9. Nov 23, 2019 #39

    lucabrasi

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    I’ve found s30v, d2, R2, xhp... to sharpen pretty routine. As pleasurable as white 1/aebl? No, but very doable. Have to be a bit more purposeful with burr removal but beyond that it’s no big deal.

    Zdp just takes longer to grind, m390 was a little tough to get a burr to form and remove. S110v seemed to be literally impossible to get a truly sharp edge without diamonds. I hated s110v. And dumped it.
     
  10. Nov 23, 2019 #40

    inferno

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    its not harder to sharpen per se. it just takes longer imo. thats what i mean.
     
  11. Nov 23, 2019 #41

    Keith Sinclair

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    Sharpen quite a few cheap house knives it is rare that I can't raise a Burr. Every now & then get a knife that to get a Burr is a challenge to say the least.
    We get spoiled by quality steel both carbon & stainless that make sharpening a pleasure instead of a chore.:)
     
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  12. Nov 26, 2019 #42

    rick alen

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    Larren's latest edge micrographs clearly showed that conventional abrasives aren't ideal for vanadium carbide rich steels, and diamond is the way to go for a sharp and durable edge.
     
  13. Nov 27, 2019 #43

    captaincaed

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    Is this M390 edge really worth it once the edge is on it? looks like a bear
     
  14. Nov 27, 2019 #44

    Barmoley

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    Only you can answer this question for yourself and your use. Properly heat treated and formed m390 edge will last much longer than "regular" steel edge between sharpening if the mode of failure for your knife is not chipping or rolling. In a cleaver m390 would make no sense at all. In a gyuto, suji, petty it will last longer than 52100 or AEB-L all else being equal. It is harder to sharpen and much harder to thin....
     
  15. Nov 27, 2019 #45

    vicv

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    M390 is really no harder to sharpen than anything else. You need the proper equipment. Unfortunately most water stones are not it. Silicon carbide stones make quick work of such steels and cleanly cut the vanadium carbides. I dont like diamond stones personally but they should work just fine too. Anyone having an issue grab yourself a Norton crystolon stone and grind that steel. For more polish get some wet and dry sandpaper in finer grits on a hard backing
     
  16. Nov 30, 2019 #46

    Keith Sinclair

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    Is anyone still making chef knives with M390?

    I know CKTG did for a while another of their dead end knives.
     
  17. Nov 30, 2019 #47

    Barmoley

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    Andrei Markin does, and does a great job.
     
  18. Nov 30, 2019 #48

    inferno

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    https://scienceofsharp.com/2015/03/01/the-diamond-plate-progression/

    but science of sharp SEM micrographs shows that anything above dmt 600 will make the steel less sharp. and the 600 creates a foil edge....

    so i guess its a double edged sword this with diamonds. wouldn't you say?

    dmt 325
    [​IMG]
    dmt 8k
    [​IMG]

    atoma 400. LOL! what a POS this would be for actual sharpening...

    [​IMG]

    ------------------

    [​IMG]
    10000x magnification of the apex cross-section after honing on the DMT Coarse (325). Edge width is less than 100nm.

    [​IMG]
    10000x magnification of the apex cross-section after honing on the DMT Fine (600). Edge width is approximately of 100nm. The apex angle is approximately 14 degrees, measurably less than the spine-apex angle of 16.5 degrees – a foil edge by definition.

    [​IMG]
    10000x magnification of the apex cross-section after honing on the DMT Extra Fine (1200). Edge width is sub-100nm in places due to convexity of the last micron of the apex. The bevel angle 3 microns from the apex is 19 degrees, but is significantly larger nearer the apex.

    [​IMG]
    10000x magnification of the apex cross-section after honing on the DMT Extra Extra Fine (8000). Edge width is not quantified due to the irregularity of the apex.
     
  19. Nov 30, 2019 #49

    kayman67

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    You need a much bigger pool to say that this is definitive. Many diamond plates, many different edges and so on. Also keep in mind that always, from my experience, the nature of the abrasive, for a particular alloy, gives a certain kind of edge that might be different with another particular alloy.
     
  20. Nov 30, 2019 #50

    Eloh

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    imo as long as you dont use diamond stones as a finisher they can be very useful
     

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