S90v vs M390 ultra thin slicer

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tjiscooler

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Mar 17, 2008
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Hey all working on a new knife and would like some opinions. It's a thin stock wharncliffe with a fairly thin tip.

Looking for thin chisel ground slicer. Tall flat grind one one side and dead flat I. The other. Blade is just under 4 inches. Haven't picked stock thickness but likely around 1/8th or so.Planning on between .009-006 behind the edge.

Hard Rockwell rating. 61-62 for m390 not sure on the 90v.
What would you pick? Which would be less likely to have the tip broken off? Any ideas on better edge retention at those numbers? Any other comments or even steel recs would be welcome. Thanks.
 
Also, I'm preffering a stainless steel. K390 looked great but I feel like it might rust too fast.
 
I would if I could man, but I know nothing. I was hoping to read some replies by sage like knife makes.
 
tjiscooler said:
Looking for thin chisel ground slicer. Tall flat grind one one side and dead flat I. The other. Blade is just under 4 inches. Haven't picked stock thickness but likely around 1/8th or so.Planning on between .009-006 behind the edge.
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It also depends on the edge angle. Normally, chisel edge would be considerably thinner vs. V grind. Given all that, I suppose you'd want something harder to support ultra thin edge.
In my experience 6-61 hrc edges don't hold up well below 15 deg angle. Depends what you cut I guess, and I'm not talking about wear resistance here, simply edge strength to avoid deformation.

tjiscooler said:
Hard Rockwell rating. 61-62 for m390 not sure on the 90v.
What would you pick? Which would be less likely to have the tip broken off? Any ideas on better edge retention at those numbers? Any other comments or even steel recs would be welcome. Thanks.
Click to expand...
S90V has better wear resistance, and M390 will have better corrosion resistance. Depending on materials and environment one or the other can last longer. If humidity, corrosive agents are not the issue, then S90V will do better, especially on abrasive stuff. If you live in highly humid env, or plan on using that knife around salt water etc, better corrosion resistance might benefit you.

Ankerson did do bunch of tests with both steels check out his thread in reviews section. In my own use, S90V does outlast M390 on cardboard, rope and plastic...

You might wanna consider CPM 10V, CPM s110V and CPM s125V along with S90V lines, 10v isn't stainless but highly wear resistant, works well with very thin edges. Al three can do 64-65HRC easily, which should help you with very thin edges.

I'll skip 1095 and other low alloy steels, they can be hardened to the high rc, but having rather low wear resistance unlikely to work for you as slicers. On the other hand, in the kitchen they do fine.
 
This will be carried with me daily and I've had 1095 rust on me even after treating with ezoox from being close to my skin I guess. I will talk to the maker/ heat treater and see what he's comfortable in working with. Haven't thought of 110v or 10v thanks for the tip.

I've been through Ankersons thread and there's a lit if good talking points and info there for sure.
 
I like M4 for really thin applications, the toughness and resistance to deformation reduce the risk of bending or cracking off parts of the blade.

Between the two steels you've named, I'd go with M390 since the finer carbides tend to rip out of a very acute edge less. I get more retention with sub-10dps edges with M390 than S90 or its relatives (S30v, S60v, S110v). Of course, YMMv.
 
any of the big carbide steels might get into some issues with edges that thin and acute. not unusable issues, but issues where a lower wear resistance steel with better edge stability might just end up having a more resilient edge.

this it's advice only from years of reading, most of my knives stay in the typical thirty degree inclusive range, where the big carbide steels really shine in pure edge retention.
 
tjiscooler said:
Hey all working on a new knife and would like some opinions. It's a thin stock wharncliffe with a fairly thin tip.

Looking for thin chisel ground slicer. Tall flat grind one one side and dead flat I. The other. Blade is just under 4 inches. Haven't picked stock thickness but likely around 1/8th or so.Planning on between .009-006 behind the edge.

Hard Rockwell rating. 61-62 for m390 not sure on the 90v.
What would you pick? Which would be less likely to have the tip broken off? Any ideas on better edge retention at those numbers? Any other comments or even steel recs would be welcome. Thanks.
Click to expand...

Since I'm not sure this has been directly answered, I'll venture to advise leave the tip thicker to avoid losing it. M390 is rated to have somewhat higher toughness than S90V via Charpy, but I doubt you'd notice a difference in a thin tip - an incident with sufficient force to break one would probably be enough to break the other as well. Neither is supremely "tough", and a thin hardened tip is a delicate thing, but keep it stout and there won't be an issue. For example, start at 10:58:

[video=youtube_share;JnAKtElk_PY]http://youtu.be/JnAKtElk_PY?t=10m58s[/video]
 
Awesome video thanks. This knife won't see any of that abuse if I can help it haha. It's mainly light edc with an emphasis on SD. I've got busse and rat to beat on! Although I'm liking what I've seen From survive so I may look into them later on for a new heavy user.
 
As far as edge acuteness goes I'm planning on a decent sized polished bevel with a strong microbevel with maybe a toothier grit to add some strength. Maybe s90 will come out on top in that case.
 
I think M390 will be better if you take good care of it. Run it at 63. It will perform better and not lose much toughness.

M390 is my favorite stainless because it cuts so aggressively when sharp and it takes a truly phenomenal edge. Its also alot easier to finish so take into account the final finish and its role in stain resistance.

S90V will be better if you want to cut cardboard all day but for anything else I think M390 is better all around. Both are pretty tough with M390 being a little tougher.
 
^ good tip on the finishing ease, thats something I kind of neglected. Maybe someday ill make my own "mule" project and try out everything.
 
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