Why Would Chris Reeve DO This???

Megalobyte

Megalobyte

Joined
Jun 5, 2002
Messages
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I have heard that the newer S30V blades Chris Reeve is using are not as hard, rockwell-wise as the older BG-42 blades. That, for some reason, CR decided to not make the S30V blades quite as hard as they could have. If this is true, why would he do that? He must have a reason, i have to believe its not laziness or cost. Any ideas? I have heard it said that by not making the S30V blades as hard as they might have, youre losing out on the main benefit of S30V, edge holding ability, true?

Also, could there be a hidden benefit to this, having a slightly softer blade, is more resilient, sort of like with differential heat treating on Japanese blades, keeping the spine softer than the cutting edge and thus more resilient?
 
Before anyone says to Megalobyte that this topic has been done to death, let me say that I've read a dozen threads on this and have yet to see a definitive statement from CRK as to why the decision was made, including the specific benefits of S30V at this hardness over BG-42. Perhaps I missed it, but I don't think so. I, too, would like to know the exact reasoning behind this.

Johnny
 
Yeah, this topic has been done way to death over on the CRK forum.

I would suggest that you give CRK a call directly, thereby getting the info directly.
 
My guess would be that they felt that 58-59 RC gave them the best combination of toughness, edge holding and ease of sharpening. Possibly during testing they found that when hardened to 60-61 RC their blades tended to exhibit some characteristics that they were not happy with. I am sure that if they felt that S30V worked better when made harder, they would have done just that.
 
How many of you remember the "chipping" problems that CPM440V steel had when it first appeared as in knife blades? It turned out that it was being hardened to an Rc level that was too high. Spyderco came out with it hardened to RC 57-59 and it worked perfectly, as the edge holding aspect of Crucible Particle Metallurgy steels, of which S30V is an example, are the carbide crystals of vanadium, molybdenum, and chromium that are held in the matrix that is the rest of the steel. It is that matrix that is Rc 57-59, the crystals are somewhere up with diamonds for hardness, as anyone who has ever sharpened a CPM440V blade, and I suspect an S30V blade as well, will tell you. It is the carbides that give the blade its edge holding ability.

Here is Crucible Service Centers' web page with a cross-reference to S30V steel. I cannot take you to the S30V page directly nor can I copy it. Note that they recommend Rc 61 as the maximum for cutlery steel uses. http://www.crucibleservice.com/cutlery.cfm#
 
Ya, but S30V isn't 440V by a long shot -- one of the big things about S30V being trumpeted is that it's somewhere between D-2 and A-2 in toughness at 59-60 Rc. That's why a lot of people are confused -- there shouldn't be any reason to leave S30V "soft" based on chipping or toughness issues, in theory.

The hazy answer I remember reading is that ease-of-sharpening was a high priority for Chris, and dropping the Rc makes sharpening easier, without sacrificing that much in wear resistance. So theoretically, you get better toughness and wear resistance than BG-42, but the S30V might be even easier to sharpen ... at the sacrifice at some hardness, which is sometimes okay, and sometimes not. It's the tradeoff that CRK determined was best for his customers.

To Megalobyte: I think your hypothesis that edge holding is the primary benefit of S30V isn't quite true. The thing S30V seems to have achieved is a great balance of stain resistance, wear resistance, toughness, and machineability ... it's that balance that should make it such a great all-around steel. If great wear resistance were all it was about, you might as well just stick with S90V. When people worry about CRK's S30V being too soft, I think they're primarily worried about strength, not wear resistance ... though of course both strength and wear resistance contribute to edge holding depending on what you're doing.

Joe
 
Disclaimer: I do not have any close experience with CRK stuff, however having some experience with a lot of other brands I could propose my conclusions in this subject.
Lowering blade hardness some deal of edge retention is sacrificed, it is unquestionable fact (in certain limits of course as everything in techniques). On the other hand the blade and edge toughness are risen by making them less brittle and prone to chipping. This is well-known fact as well, again in certain limits.

Now the question is only which blade property is more important for a user. IMO you always can touch up your slightly blunted blade as far as you have it in one piece and not chipped badly.
 
It's of interest that a discussion was generated on the CRK forum a few weeks ago. It appears that the new S30V Sebenza blades were chipping more easily than the older BF-42 Sebenza blades.

On the other hand, it appears that the same hardness levels work very well with the Simonich Mid-Tech Raven. Apparently the edge geometry and bevel play an important part in the equation. So, as a few folks have been trying to get across, there's a lot more to a blade than the type of steel.
 
Look at the grind and edge geometry. The Simonich Mid-Tech knife may have the same blade steel but, that is where it ends. It has a totally different "grind" strength quality. Not having owned a Mid-Tech personally, I cannot speak to the quality of the grind or edge definitively but, I suspect if it was made out of any steel it would offer strength the CRK folders would never have. If you wanted a Saber ground thick folder, CRK could probably kick up the RC value a little but, would you have a knife that cuts like you expect the CRK folders too?

A lot has been made of the "softer" CRK process but, is it really that bad? Do you still get your edge holding? How difficult is it to resharpen? HOW MANY OF US COULD ACTUALLY TELL THE DIFFERENCE IN NORMAL USE?

My soft Sebenza will still out perform all but the very best handmades out there in the marketplace. While many of us steel addicts and fellow forum'ites would be able to tell the difference, the vast majority of the CRK customer base will never notice the difference in ATS-34, BG-42 or, CPM 30V except for the older hand ground knives without the pocket clip. Literally, the pocket clip is what they wanted! Not blade steel or RC value!
 
blah blah blah hooody hooody hooo... so what is the verdict??? SEEMS to me that stainability, sharpenability and manufacturer cost are the ONLY things S30V has over BG42.

AND

WHAT'S THIS ABOUT CHIPPING???? NO BUENO!

I plan to get a Mnandi, which I will baby, thus stain resistance would be great, and I wouldnt go stabbing it into car panels, so who cares about the chipping thing.

HOWEVER

My seb is a WORKING KNIFE and is the big dog on the block as far as a regular Joe's collection goes (like me) AND I'd like to think that I can tackle any reasonable (no metal, bricks, ect...) cutting chore WITHOUT A CHIP!!! MY BG42 HAS Passed EVERY chore I've put It's way, and even MY guitar playin' a$$ can sharpen that thing "hair poppin" sharp in no time. Not to mention... I learned to sharpen on my Seb...

SO

What IS the deal?
 
Another thing... I dont thing ANY OTHER knives really matter in this discussion... The discussion is steel, and I would think that it's pretty obvious that a different design and heat treating method would change things.... almost like apples and oranges.

Take a S30V sphere

and a BG42 cube

and drop them off the highest building in town... Are you gonna learn what steel is better or which shape is better?


The answer is... you droped the cube wrong.

I think it is IMPORTANT to discuss SEBENZA BLADES here.

BTW

I think that apples are better than oranges unless I'm out on a long hike... then there is nothing like a big ol' orange....

:)
 
Originally posted by archieblue
SEEMS to me that stainability, sharpenability and manufacturer cost are the ONLY things S30V has over BG42.
Click to expand...

Uh, actually, S30V is more expensive to grind and finish by some small margin. I don't have raw stock pricing, but suspect S30V is more expensive to purchase in raw stock form also.

And since S30V has better wear resistance at a given hardness, it's sharpenability is going to be somewhat worse (more vanadium) at a given hardness.

S30V is in fact somewhat better in the stain resistance dept, depending on heat treat.

S30V is marginally better than BG-42 in pretty much every aspect except expense to buy and finish, not by huge margins, but it is the best balanced stainless going. It is up to the maker to grind and heat treat to bring these improvements to bear in a working tool.
 
Joe Talmadge pretty much hit the nail on the head with his explanation.

But, instead of asking the masses and possibably not getting the correct answer. . .I'd suggest that you e-mail or call CRK.

Better yet. . .toss a thread asking the question on their forum on this site. :confused:

Kinda funny. . .on the CRK web site. . .it says;

For more information on Chris Reeve Knives products, please contact:

Chris Reeve Knives
11624 W. President Dr. #B
Boise, ID 83713
www.chrisreeve.com 208-375-0367

I wonder why they put stuff like that on their site ? :rolleyes:

;)
 
Joe Talmadge :

... there shouldn't be any reason to leave S30V "soft" based on chipping or toughness issues, in theory.
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The impact toughness of S30V from the Crucible data sheet is nothing to be excited about. It is similar to D2 which is one of the most fragile tool steels. The testing done by Rob Simonich reflects this, with the knife breaking under cutting which isn't a problem for the more durable tool steels. I have done similar cutting, using fewer hits, and thus greater levels of impacts with nothing but cosmetic damage to blades like the TAC-11, through multiple sections (three with that particular blade). It however does break most stainless blades, the SOG SEAL broke in half after just a couple of light hits.

http://www.physics.mun.ca/~sstamp/images/tension_bar_knives.jpg

The top blade is a Martindale machete. The impacts were not a problem for the main body of the blade, but I had lowered the edge angle too far to allow it to handle the metal impacts. The edge indented significantly and the cutting ability took a nosedive. The handle fractured shortly thereafter, a horizontal split running the full length of the grip. It was easily repaired with some glue. The edge was cleaned up on a belt sander in a few minutes. The TAC-11 suffered some minor edge damage, ~0.5 mm deep in a few places. I was hammering on it heavily towards the end as I tried to make the last cut in just six hits. Plus I was chopping on a concrete step so the last hit would jam the blade off the rocks in the concrete with in retrospect did more damage than the tension bar cutting.

It is an interesting test, I am not 100% on it yet as I have not done it with enough knives, I intend to do it with a Mission MPK in A2 and Ti as well as some other blades like the Swamp Rats and such, I just need to get some more tension bar. Based on what I have seen, it is similar to cutting 3.5" nails, just takes longer because of having to wedge the bar apart. If you had to actually do this for some reason, you only need to notch the bar and then you can bend it and it will split without excess difficulty, there is no need to hammer the blade all the way through. You could also just score it with the tip multiple times, etc. .


-Cliff
 
Plus I was chopping on a concrete step so the last hit would jam the blade off the rocks in the concrete with in retrospect did more damage than the tension bar cutting.
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A stump may be a better chopping block than concrete step. I have never tried using a concrete step for a chopping block, and I don't think I ever will.

That A8 is some tough steel though and has been heat treated to maximize its toughness, so the fact that a stainless steel steel like S30V does not fare well in comparison is not too shocking. Also the simple carbon steel (like 1070 right) in the Martindale, heat treated to mid 40 Rc is not a great comparison either.

I have a single knife in S30v (benchmade 921) and have found it to be a very fine grained steel capable of taking a very fine edge. The knife type is not one suitable for heavy work. I have a large custom bush blade (12" blade, 3/16" thick) on order in S30V and I have no fear that it will fail; though I may change it to A2, as I am not concerned about corrosion resistance for this blade, and I have no need for the wear resisitance.

Trace Rinaldi is using S30V in some large blades and has seen good results.
 
Originally posted by Eric_Draven
I have a large custom bush blade (12" blade, 3/16" thick) on order in S30V and I have no fear that it will fail; though I may change it to A2, as I am not concerned about corrosion resistance for this blade, and I have no need for the wear resisitance.
Click to expand...


Eric,


If you have the option, you might want to consider CPM3V - Crucible's data sheets show it as having about the same wear resistance as CPM30V with toughness much greater than A2.


-Frank
 
Cliff Stamp:
The impact toughness of S30V from the Crucible data sheet is nothing to be excited about. It is similar to D2 which is one of the most fragile tool steels.
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Cliff, D2-level toughness might not be interesting if we're talking about tool steels, but it's interesting when we're talking about highly-wear-resistant stainless steels, IMO. If it's true, it should be a nice lift above ATS-34, VG-10, BG-42, etc. That's a real achievement, IMO. Again, if it's true -- some Sebenza stories cast a little doubt on it.

Joe
 
Joe Talmadge :

[S30V]

If it's true, it should be a nice lift above ATS-34, VG-10, BG-42, etc.
Click to expand...

ATS-34 is in the same class, the difference in toughness between it and S30V isn't significant according to crucible.

Erik :

[A8]

.. the fact that a stainless steel steel like S30V does not fare well in comparison is not too shocking.Also the simple carbon steel (like 1070 right) in the Martindale, heat treated to mid 40 Rc is not a great comparison either.
Click to expand...

The toughness of S30V has been promoted above A2 so comparing it against tool steels is obviously warrented. As for the knives specifically, the Martindale was chosen as I wanted to see the extent that the low RC would limit the performance and how the handle would hold up to the vibration. As expected, even though the impact toughness isn't exceeded, the plastic limit is rather easily, which is one of the problems in general for such hardness levels. The TAC-11 was chosen as an upper limit, as it is one of the tougher blades on the market, both because of the steel and the edge geometry. As noted in the above, other knives will eventually see the same cutting.

In regards to using a block of wood. I didn't have any on hand which was hard enough to withstand the impacts. The bar would too readily be driven into the wood. You have the same problem cutting nails, the nail will end up v'd into the wood and will wrap aound the blade. You can actually do it with less damage to the edge if you chop (carefully) using a flat rock as a chopping board, mild steel plate is about optimal. I was not concerned about the effect of the step in the above cutting as I was mainly interested to get a feel for the level of force required to cut the bar in around ten hits. This was easily exceeded using a Estwing framing hammer. The only problem was that at the end I was unable to conclude if the small damage done to the TAC-11 was due to the bar or the rock/concrete contacts. This I will check later on when I get more bar, as noted, this was mainly a trial run just to set some benchmarks.

-Cliff
 
Frank,
If you have the option, you might want to consider CPM3V - Crucible's data sheets show it as having about the same wear resistance as CPM30V with toughness much greater than A2
Click to expand...

I had considered it, especially with a hard Chrome and BC coating. But I don't need wear resistance in this type of blade as I will not be doing any slicing and no significant grass or fiberous work more for medium chopping, so I just a fairly high level of strength so that I can run the edge thin, and a good toughness so that it does not chip out. Wear resistnce here would only result in harder sharpening.

Cliff,

Have you used S30V yet or are you making these claims based on the specs sheet and thrid and fourth hand claims? No problem either way, just wondering if you have had any direct experience.
 
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