# M390 - sharpening recommendations and/or progressions?



## thebradleycrew (Nov 14, 2019)

Hey folks,

I've got a couple knives in M390 and am looking for guidance from those with experience on how they get a good edge and what stones/progressions they use. I've found it to be fickle thus far on most of my natural stones (aoto, aizu, Swedish los hone, Suita) and so am thinking I need to keep it on straight synthetic. Do others have similar feelings or experiences?

Thanks!


----------



## Barmoley (Nov 14, 2019)

I've had best results with gesshin 1k, Gesshin 4k or 2k + 4k. If you want a bit more refinement diamond loaded leather strop gave it a bit finer edge with still byte left. Gesshin 1k + loaded leather strop worked well too. Swedish los hone did not work as realiably for me.


----------



## Eloh (Nov 14, 2019)

Generally speaking, Shapton Pro works fine even with higher alloyed steels, a 2k/5k or 2k/8k progression should work fine as a general sharpening progression. DMD Diamond stones work fine with everything you throw at it too.


----------



## KingShapton (Nov 14, 2019)

Shapton Pro and Glass should work, Sigma Select II should be even better / faster and any kind of diamond plate should work as well.

Starting with synthetic stones for the "heavy lifting" and making the finish with a natural stone should work as well.

For example, Sigma Select II 1000, Sigma Select II 3000 and natural stone.


----------



## danemonji (Nov 14, 2019)

I have sharpened m390 outdoor knife and even k390(which due to large amount of vanadium is abrasion resistant) on suehiro 1000/6000 50$ stone. Removed microbevel and went for zerogrind on both. The m390 is quite ok to sharpen and on the 1000 grit you should have no problem cuting into the steel. The 6000 will give a nice polish and finish the blade to razor sharpness


----------



## inferno (Nov 14, 2019)

https://www.alphaknifesupply.com/shop/m390-stainless-steel

looks like its 
1,9%C 
1% Mo
0,6% W
4% V 

interesting choice of alloying elements. lets just say it wasn't designed to be easy to sharpen. this is probably on of the most abrasion resistant SS on the market.

if you intend to just sharpen you can use pretty much any of the often recommended brands. maybe a 1k and and a 3 or 4k. jns/naniwa pro/jki/shapton (both series)/king hyper and so on.
if you intend to do chip removal, thinning, reprofiling i would get a coarse diamond plate 2-400 as the starter stone and follow up with a 500 or 1k non diamond.

whatever you get i would get hard/slow wearing stones for this since i have a feeling this steel can wear off quite a bit of stone otherwise with all those carbides.


----------



## thebradleycrew (Nov 14, 2019)

All great feedback, folks. I have a Shapton galsstone 500 and Gesshin 4k, so that is a great starting and finishing place. I agree with @inferno that the steel is really quite resistant to abrasion in my limited experience, but boy once sharp it is awesome. I'll find a slow wearing 1k or 2k and roll from there. Probably go Gesshin!


----------



## inferno (Nov 14, 2019)

get whats cheapest of the known good brands imo.

i think i have owned about 10 or so 800-1k stones now. and i still have maybe 5-6 of them.
I think the absolutely slowest wearing one is the jns1k (soaker), closely followed by both shaptons (splash and go), naniwa hibiki (soaker). and also the missarka 500 (800jis) is extremely slow wearing since its basically a single block of slightly porous alox https://www.fine-tools.com/kuns.html this one is also a soaker, and it feels like crap compared to all other stones.


----------



## thebradleycrew (Nov 14, 2019)

inferno said:


> get whats cheapest of the known good brands imo.
> 
> i think i have owned about 10 or so 800-1k stones now. and i still have maybe 5-6 of them.
> I think the absolutely slowest wearing one is the jns1k (soaker), closely followed by both shaptons (splash and go), naniwa hibiki (soaker). and also the missarka 500 (800jis) is extremely slow wearing since its basically a single block of slightly porous alox https://www.fine-tools.com/kuns.html this one is also a soaker, and it feels like crap compared to all other stones.


Have you tried the Cerax 1k? Looks like a $45 stone just not sure how it performs.


----------



## inferno (Nov 14, 2019)

also if you're looking for similar steels to this. r2/sg2 and srs15 is similar to this, but will be easier to sharpen most likely. and probably get sharper too. many japanese brands use these 2 as their premium stainless.


----------



## inferno (Nov 14, 2019)

no not tried the any cerax actually. and only one king (the hyper 1k). for some reason i have no interest in ceraxes. but i will probably get a few sooner or later anyway.

the shapton pro is usually very cheap. around the 45€/$ mark and imo this is the best price/performance/longevity/dish resistant stone you can find in the 1k segment on this planet. and i have tried a few of them.


----------



## Kozuka (Nov 14, 2019)

You might want to ping @suntravel on this. He did extensive testing on M390. He also built a knife for me out of M390. It's a ***** to sharpen if you want a super clean edge. If you just want to get good edge that stays a while it's actually not that bad.

See: https://www.instagram.com/p/BoB_wKSgfWb/


----------



## Matus (Nov 14, 2019)

It might be interesting to talk to kknives_switzerland on IG. That guys use it too and gets it to split hairs.


----------



## Barmoley (Nov 14, 2019)

I haven't found m390 that difficult to sharpen, but I haven't tried to make it shave hair just by being in its proximity either. For example ZDP-189 has been more difficult, same for s90v, s110v and then there is s125v if we are talking about stainless.

This stone might work very well too https://www.mtckitchen.com/king-neo-800-knife-sharpening-stone-st-3/ I have it but haven't tried it yet. If you want I can mail it to you and you can try it and report back. 

Gesshin stones work very well for me, but if you want ultimate you could get Jon's diamond stones, I'm sure these would work great too.


----------



## danemonji (Nov 14, 2019)

thebradleycrew said:


> Have you tried the Cerax 1k? Looks like a $45 stone just not sure how it performs.


Cerax 1k(suehiro) is a fast cutting stone. Harder then most synthetic stones. It should have no problem working on your m390.


----------



## KingShapton (Nov 15, 2019)

inferno said:


> this is probably on of the most abrasion resistant SS on the market.


The Sigma Select II have been made to handle extremely abrasion resistant SS. The other suggestions will work too, but Diamonds or Sigma Select II will be much faster.

I can not say anything about the Geshinn stones, unfortunately I do not know them.


----------



## inferno (Nov 15, 2019)

doesn't sigmas wear fast as hell?


----------



## kayman67 (Nov 15, 2019)

I did lots of work with them on stainless. Always soaked. Just let the abrasive do its job.


----------



## inferno (Nov 15, 2019)

likes/works with low pressure?


----------



## kayman67 (Nov 15, 2019)

Yes. And water before they are used. Even the very fine seemed to like water quite a bit.


----------



## M1k3 (Nov 15, 2019)

Sigma Select is hard, the Select II is soft.


----------



## KingShapton (Nov 16, 2019)

I have the Sigma Select II 1200, which is pretty tough. The 1000 is a lot softer, but it's also 30mm high and it's very fast. He wears faster, but the speed with which he removes metal relativizes that.

And I use the stones only on very wear-resistant steels. For everything else, I prefer Shapton.


----------



## suntravel (Nov 16, 2019)

DMD Diamond 6 and 12k, Shapton 30k and Nakayama, but with system and pressure control 

Regards

Uwe


----------



## lucabrasi (Nov 16, 2019)

Cerax 1k and 6k have both been very effective for me on m390/20cv/204p steels. The 1k especially raises and removes a remarkably clean burr. Big fan of both stones.


----------



## KingShapton (Nov 17, 2019)

lucabrasi said:


> Cerax 1k and 6k have both been very effective for me on m390/20cv/204p steels. The 1k especially raises and removes a remarkably clean burr. Big fan of both stones.


Have you ever tried the Cerax 5000 for comparison with the Cerax 6K?


----------



## lucabrasi (Nov 17, 2019)

No experience with the 5k. I have the 320, 1k, and 6k. 320 moves a lot of steel but wears very fast. It cuts much faster than my Chosera 400, but I mostly use the Chosera because it holds its shape. Do use it for major thinning jobs. It definitely cuts PM steel. 

The 1k and 6k are my go to stones. That includes all my kitchen carbons and a bunch of zdp, xhp, s30/35, m390, 3v steels. 

They’ll be useless against s110v, don’t know about s90v. S110 requires diamonds in my experience, which I hate sharpening on so I just dumped the s110v.


----------



## ipq7 (Nov 18, 2019)

Shapton Pro works quite well on M390 blades. I usually start with 1k, change to 5 and/or 8k and finish on 12k or Nat.


----------



## boomchakabowwow (Nov 18, 2019)

i am not a pro like some of you. M390 + Shapton 500 + ME = nothing but frustration. it sucked so bad i was not using my knife in the hopes of preserving the edge. screw that.

i bought into the Diamond game. i am using the Lansky. i took my edge beyond factory sharp. i now rock the knife daily.


----------



## Barmoley (Nov 18, 2019)

Some pocket knives are difficult to sharpen free hand on stones no matter the steel because of the shape of the blade or edge going all the way to the handle or having flipper ridge, hand guard, etc. The one in the picture actually looks ok in that regard. For some pocket knives lansky, edge pro or Spyderco sharpmaker are just easier. Sharpenning a long and tall gyuto on one of these can be its own pain thought. Diamonds don't hurt either.


----------



## inferno (Nov 18, 2019)

and for reverse curved blade you cant even use a stone...
the bigger the blade the better it is with stones.

there is definitely a learning curve when sharpening pocket knives on stones. i dont do it in any way similar to the way i sharpen big blades. because it wont usually be good or work at all. 
the smaller the blade the more spine leading i do. sometimes from heel to tip sometime reverse, sometimes a kind of swirly motion, all depending on the shape of the blade. 

find one method that works and use it! easy as that.

my work moras i sharpen on folded sandpaper. its cheap, it works, its fast.


----------



## inferno (Nov 18, 2019)

boomchakabowwow said:


> i am not a pro like some of you. M390 + Shapton 500 + ME = nothing but frustration. it sucked so bad i was not using my knife in the hopes of preserving the edge. screw that.
> 
> i bought into the Diamond game. i am using the Lansky. i took my edge beyond factory sharp. i now rock the knife daily.



you could also look into one of these small dmt folding diamond ones. its would probably work ok for that blade.


----------



## k7598 (Nov 18, 2019)

For me the DMDs work slightly better than the Shapton Pros.


----------



## kayman67 (Nov 18, 2019)

inferno said:


> and for reverse curved blade you cant even use a stone...



Actually, you can, but on a Glass would be just very poor doing. 
I make new bevels for these on stones alone.


----------



## MrHiggins (Nov 19, 2019)

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.


----------



## vicv (Nov 20, 2019)

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


----------



## lucabrasi (Nov 20, 2019)

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.


----------



## Keith Sinclair (Nov 22, 2019)

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.


----------



## inferno (Nov 22, 2019)

lucabrasi said:


> 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.



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.


----------



## lucabrasi (Nov 22, 2019)

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.


----------



## inferno (Nov 22, 2019)

its not harder to sharpen per se. it just takes longer imo. thats what i mean.


----------



## Keith Sinclair (Nov 22, 2019)

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.


----------



## rick alen (Nov 26, 2019)

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.


----------



## captaincaed (Nov 27, 2019)

Is this M390 edge really worth it once the edge is on it? looks like a bear


----------



## Barmoley (Nov 27, 2019)

captaincaed said:


> Is this M390 edge really worth it once the edge is on it? looks like a bear


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....


----------



## vicv (Nov 27, 2019)

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


----------



## Keith Sinclair (Nov 29, 2019)

Is anyone still making chef knives with M390? 

I know CKTG did for a while another of their dead end knives.


----------



## Barmoley (Nov 29, 2019)

Andrei Markin does, and does a great job.


----------



## inferno (Nov 29, 2019)

rick alen said:


> 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.



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




dmt 8k





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






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





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





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.*





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.





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.


----------



## kayman67 (Nov 30, 2019)

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.


----------



## Eloh (Nov 30, 2019)

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


----------



## rick alen (Dec 12, 2019)

Those particular diamond plates are obviously not the way to go. I should think Jon's 6K diamond stone would give superior results to any low-grit DP. And, of course, there is always the diamond-loaded strop, whose merits are unquestionable. 3M diamond sheets also.

I think it's clear that to get the best out of Vanadium carbides you need an abrasive that is harder than those carbides.


----------



## Bolek (Dec 12, 2019)

For D2 (I do not have any M390 )boron carbid works quite well.


----------

