M390 - sharpening recommendations and/or progressions?

[inferno]

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]

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

 

[kayman67]

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]

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]

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]

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]

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]

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]

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]

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

 

[Keith Sinclair]

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]

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]

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

 

[Barmoley]

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]

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]

Is anyone still making chef knives with M390?

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

 

[Barmoley]

Andrei Markin does, and does a great job.

 

[inferno]

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...

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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]

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]

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

 

[rick alen]

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]

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