S30V vs M390 Toughness?

jstn

jstn

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I know M390 beats out S30V in terms of edge retention by a wide margin, but I haven't been able to see a comparison with toughness. Anyone know which is tougher and by how much? Thanks
 
There is no hard and fast answer, as too much depends on heat treat, blade thickness, grind, and edge geometry.
 
RevDevil said:
There is no hard and fast answer, as too much depends on heat treat, blade thickness, grind, and edge geometry.
Click to expand...

Rev, where would I learn about stuff like this? especially grind and blade geometry
 
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jstn said:
I know M390 beats out S30V in terms of edge retention by a wide margin, but I haven't been able to see a comparison with toughness. Anyone know which is tougher and by how much? Thanks
Click to expand...


Here you go.

S30V CRK Green beret (almost .25" in thickness and fat blade geometry)

http://youtu.be/3sJ82NQ3Pjk

Survive! Knives GSO 4.1 in M390

http://youtu.be/gFzI9U64bjg (.156" Thick with a slicer geometry)
 
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rxavage said:
Rav, where would I learn about stuff like this? especially grind and blade geometry
Click to expand...

Just pay special attention to what manufacturers say. People like Sal Glesser, Phil Wilson, Paul Bos, and a ton of others can provide their experiences. Read some of the threads in Shoptalk, the makers in that section have a ton of great information. Bladeforums is one of the best resources, you are already here. ;)
 
Grind and geometry are easy to "understand" (at least what we're talking about), but finding the "perfect" grinds and geometries is a whole other ballgame.

The whole thing to remember is this. Knives are just things that make force come to a very, very small area (as in, the force is concentrated on the edge). Knives are also just about angles. As clearly if you're trying to cut something, the thinner (more acute) the angle, the easier it will separate the material. So basically knives are just triangles.

So when we say "geometry" we're literally just talking about the angles involved in the "triangle" that is the knife blade. For instance .25in is a VERY thich spine thickness for a knife. But if the face of the blade was 4inches tall, the geometry (the angles would make a tall thin triangle), would still make it a pretty good slicer. Whereas you take that same thickness (.25in), and make a knife whos face is only 1 inch tall, that geometry would be much more obtuse (or "thick", because it would be a much shorter squatter triangle).

So its all about getting the right ratios and proportions to make a knife cut well, but not break when you're using it. That comes down the steel that is used, the geometry, and the heat treat. In general, harder heat treats leave blades more brittle, while softer heat treats make it tougher, but sacrifice edge holding.

Oh and the main grinds are:

Full flat
Saber
Convex
Scandi
Hollow

Those should be easy to look up the differences on.

Good luck :).
 
RevDevil said:
There is no hard and fast answer, as too much depends on heat treat, blade thickness, grind, and edge geometry.
Click to expand...

I think he means as a general statement ,kind of like asking whats tougher 5160 or 1095.
 
RevDevil said:
There is no hard and fast answer, as too much depends on heat treat, blade thickness, grind, and edge geometry.
Click to expand...

Thanks Rev. I was specifically wondering about the S30V PM2 and the M390 (or 204p equivalent). So in this instance, with the same geometry, blade thickness, etc. is there much difference between the toughness of the two steels?
 
jstn said:
Thanks Rev. I was specifically wondering about the S30V PM2 and the M390 (or 204p equivalent). So in this instance, with the same geometry, blade thickness, etc. is there much difference between the toughness of the two steels?
Click to expand...

IN that case... :) I would say the M390 is a tougher steel. But in general, not all makers do the same thing to the steel or follow the recommended heat treating protocol. It can and does vary a great deal. You probably already knew that though. Just reiterating for the new folks. :)
I know a little about the Para2, old pic and that is incomplete and only sprint runs.
NISfbzll.jpg
 
knife chop said:
Here you go.

S30V CRK Green beret (almost .25" in thickness and fat blade geometry)

http://youtu.be/3sJ82NQ3Pjk

Survive! Knives GSO 4.1 in M390

http://youtu.be/gFzI9U64bjg (.156" Thick with a slicer geometry)
Click to expand...

So you have blades of different thickness tested by entirely different methods (one tested by the knife's manufacturer). How do those say anything about comparing the toughness of the steels?
 
Thanks for the info Rev and no thanks for the pic. It makes my collection feel inferior :D
 
Holy crap, Rev! That's quite the para 2 collection:thumbup:

Any chance you'd be willing to sell one of those grey's? :D
 
At this point, I will hang onto them for a rainy day. I've had about a dozen people ask me over the years to sell one but it's my favorite Spyderco (tied with the Military). ;)
 
RevDevil said:
IN that case... :) I would say the M390 is a tougher steel. But in general, not all makers do the same thing to the steel or follow the recommended heat treating protocol. It can and does vary a great deal. You probably already knew that though. Just reiterating for the new folks. :)
I know a little about the Para2, old pic and that is incomplete and only sprint runs.
NISfbzll.jpg
Click to expand...
And I thought I liked PM2 s. Very nice.
 
RevDevil said:
At this point, I will hang onto them for a rainy day. I've had about a dozen people ask me over the years to sell one but it's my favorite Spyderco (tied with the Military). ;)
Click to expand...

Fair enough! I'd probably do the same if I were in your position:)

Speaking of m390, I've got and m390 mini Ritter grip inbound that should be arriving tomorrow. I'll do my best to put the steel through its paces :thumbup:
 
ZT M390 is very tough, I accident hit the edge onto my tile flooring while cutting some cardboard, it just rolled....
Whereas I'm pretty sure the S30V on my Sage and PM2 will chip like crazy.

From my testing for cutting cardboard(corrugated fiberboard) cross the flute, s30v and s110v chips.
M390 has no problems... Although that being said, ZDP still triumphs them all for cardboard killing.
 
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