S30V: Is it really 'that' bad?

Twindog said:
The thing that bothers me about these threads is the notion that these steels are so similar that no one can tell the difference. That's not true. Look at Ankerson's epic thread. Some steels get barely a hundred cuts. Others go over a thousand. You couldn't tell that difference?
Click to expand...

Can someone point me in the direction of this this thread? I would like to read it but I can't find it searching from my phone.
 
RLDubbya said:
There's a lot here, a whole lot. I'm tired, and ready to give my mind a break, but: thank you for taking the time. I would like to ask you one question which might help me better understand.

Is it the case that heat treatment A (HT-A), used for S30V, is the same as Heat Treatment B (HT-B), used for S110V? If so, that goes a long ways towards helping me understand; I thought that there was a unique and different process for HT-A and HT-B.

Furthermore, I thought that it could be the case that a company (keeping it hypothetical for now, let's call it HideHerBloat) who wanted to be truly state-of-the-art would use a heat treatment company for S30v who specializes in HT-A and has developed certain proprietary processes for HT-A only. HideHerBloat would also choose a different company for the HT-B process on its S110v, and that company likewise would specialize in the HT-B process only.

If you are holding that HT-A and HT-B are fundamentally identical, that's super. Can you point me towards solid, referenced research material on metallurgical processes for heat treatment that might teach me more about this HT-A and HT-B?
Click to expand...
I am not saying that the HT process is identical for differing alloys. What I am saying is that if "HideHerBloat" ("HHB" from here on out) was a company that was interested in turning out quality knives, then they would have a maximum failure rate (and likely a high percentage at least). Lets say 98% must pass QC with one knife/blade every 20 pulled for QA testing (hardness, edge stability, toughness, et al).

Theoretically, this 98% shouldn't change with the alloy being HT'd, unless it is a significant change (San Mai, Pattern Welded, Very high alloyed/nearly solid carbide like Maxamet). With both S30V and S110V both being a highly alloted stainless steel, they should both meet the (hypothetical) 98% acceptable rate.
Differing HT protocol aside, a standard for failure amount should be in place, otherwise, how would they know if an entire batch is acceptable or not?

That being said, say two knives make it out into the hands of one consumer. HHB S30v and HHB S110v should both have had comparable screening to be acceptable, functional knives per batch.

If the HHB S30V doesn't hold an edge as long as the S110V, that is to be expected. If the S30V holds an edge longer, than I would expect some form of issue. Hand sharpen and retry the usage. If it still doesn't work as it should, send it back.

But to immediately assume that the HT is faulty on the S30V because it doesn't hold an edge as long as a blade that has higher edge rentention in an abrasive cutting material, is ridiculous.

As I have stated earlier. Find the alloy that should suit your needs best, and do targeted research.
Find out if another will suit you better.
Find out who HTs the alloy best.
Find out who has a reputation for honesty and how they treat their customers, of you end up needing them, you don't want to fall flat now...
 
NJBillK said:
Don'tfoeget, this test does not take into account for material being contacted after the cut.
After many cuts, the base will be softer, thus promoting less edge damage or abrasion than a fresh board.

I propose that he cuts over a channel cut in the board so he doesn't contact anything aside from the rope, lest the tests be less accurate.
Click to expand...

Also, the knives are just factory knives with various edge thicknesses and unknown heat treat... So not a steel test to begin with, but a knife test.

And yet, despite the board contact issue (on top of all this), all the results are minutely precise to the point of stacking dozens of different steel in seven or more different categories(!!!)... And wouldn't you know it, the results are all pretty much what you would expect if you ranked the steels by the stated content, the resulting reputation, and this combined with their novelty... Absolutely no surprise in sight across dozens of steels... Sheer coincidence of course...

To give some perspective, Cliff Stamp could not find any meaningful differences between k390 , M4 and VG-10, and hardly any with a $1 Chinese knife in something like 420... He also explain well how you have to mix up and "randomize" samples to even up huge material variations (10 to 1 differences in similar-looking cardboard in some case):


He also explains very well the issue of "cognitive bias"... Seeing a steel classification that "makes sense" (based on content/newness/reputation etc) is a big red flag that this is what is going on here... See his conclusion on that point...

Gaston
 
Gaston444 said:
Also, the knives are just factory knives with various edge thicknesses and unknown heat treat... So not a steel test to begin with, but a knife test.

And yet, despite the board contact issue (on top of all this), all the results are minutely precise to the point of stacking dozens of different steel in seven or more different categories(!!!)... And wouldn't you know it, the results are all pretty much what you would expect if you ranked the steels by the stated content, the resulting reputation, and this combined with their novelty... Absolutely no surprise in sight across dozens of steels... Sheer coincidence of course...

To give some perspective, Cliff Stamp could not find any meaningful differences between k390 , M4 and VG-10, and hardly any with a $1 Chinese knife in something like 420... He also explain well how you have to mix up and "randomize" samples to even up huge material variations (10 to 1 differences in similar-looking cardboard in some case):


He also explains very well the issue of "cognitive bias"... Seeing a steel classification that "makes sense" (based on content/newness/reputation etc) is a big red flag that this is what is going on here... See his conclusion on that point...

Gaston
Click to expand...
- How can he ensure that his edge angles were identical with a bench stone and not a higher end guided system?
- He didn't say anything about the actual geometry of the knives. (YOU of all people should have caught that...)

It is just that easy to poke a hole in your arguement. Please don't try again Gaston. The ones that your info infects, is the new folks that don't know any better.

How's the sock doing? Did that have a hole poked in it too?

Eta: Wouldn't this whole video actually be an arguement For Ankersons tests, since he cuts (basically) the same material, minus the board he is cutting upon?
 
Before trying to poke a hole in my arguments (which were mostly quotes from other people), try to write a post that is actually coherent with intelligible sentences. I could not make head or tail of what you were trying to say...

Gaston
 
Twindog said:
Say you work in a warehouse and have to cut up a lot of cardboard each day. You could get a Spyderco Military in CTS-XHP or a Spyderco Military in S110V. You think steel means nothing, so you go for the first. Your buddy has read Ankerson's thread on edge retention and goes for the S110V model. In actual testing, the CTS-XHP makes 240 cuts before dulling to a specific dullness. The S110V Military gets 1,080 cuts before it reaches that same level of dullness.

Your buddy goes all day without having to sharpen his Military. You have to sharpen yours 5 times during the day. The boss notices. Your buddy gets a raise. You get the boot.
Click to expand...

Yeah guy! Simple cause and effect.

Ain't it the truth.
 
Ok, lets break these down for you...
NJBillK said:
- How can he ensure that his edge angles were identical with a bench stone and not a higher end guided system?
- He didn't say anything about the actual geometry of the knives.
Click to expand...
He speaks of bevel angle as being a set and measured angle. How so?

He sharpened on a bench stone. No unaided human hand can set an angle and be repetitive enough to say "this is a 15° angle" across four knives of differing blade heights and thicknesses.

More on the blade thicknesses; He doesn't state a measurement of how thick BTE the knives are. This would have an effect how much wedging would be incurred by cutting through the medium. The harder it is to cut an object, the more force needed. The more force needed, the easier it is to damage the apex.

The height of the blades would also have an effect. The taller kitchen knife would want to track straighter due to the flats guiding the edge, where as the shorter blades would want to steer more, causing side loading and uneven apex wear and increase potential for damage from "dirty" cardboard.
NJBillK said:
Eta: Wouldn't this whole video actually be an arguement For Ankersons tests, since he cuts (basically) the same material, minus the board he is cutting upon?
Click to expand...
Now for this part.

If Ankersons test only cuts into one material, made to a set standard, wouldn't this yield a more constant result?
In the video you linked, I understand that he is trying to account for a real world scenario, a chaos effect. But if you are trying to test an absolute, that should be mitigated as best as possible.

Which alloy holds an edge better, A or B?
Hrm, let me cut some potentially dirty cardboard with one and potentially clean cardboard with another. If this isn't controlled, this is entirely possible.
- This shouldn't happen. Yes, it will even out, but over what spread? One meter, 10, 50, 5 million?

Cut one material with comparable contaminants within each, not just guessing they are going to even out by the time you are done...

Mind you, this is barring the contact of the wood, which I do agree is detrimental to his results and Ankerson would likely get a more accurate reading if the wood contact was taken out of the test. This can easily be accomplished by milling out a notch that the blade can cleanly pass through.

A fresh board will yield a harsher contact surface for the knife edge but as the test progresses, it will become less of a factor (to a degee) since the board will degrade under the cutting edge. This offers a softer contact area for the knife edge.

This variable should be eliminated.
-------
Is that clear enough for you G Gaston444 , or would you like me to spell it out further?

Just so you know, if you are quoting someone else, that means you are in agreement, (especially if you use it as a defense for your point) unless you state otherwise. So saying that they are someone else's quotes as a defense as to why you aren't wrong, is ridiculous.

You made a statement, now either stand by it or admit you are wrong.
 
Last edited:
Some Thoughts on Knife Blade Steel Impact Toughness
http://www.seamountknifeworks.com/articles/Knife_steel_impact_toughness.pdf

the pdf is better formatted. and this is relative to PHIL WILSON and his heat treat, which is better than most custom makers HT. but is also very old, and HT protocols may have improved since. im not an expert in this.
The Charpy test is a measure of the impact toughness of a tool steel. This is measured in ft-lbs and represents the energy required to fracture a notched test piece under laboratory conditions. When you are talking about Charpy values you are talking about impact resistance and toughness. Brittle is the opposite of tough. Typical Charpy values for some of the knife steels we use are: 154CM/ATS 34, D-2 and S90V, at RC 60 are in the 16 to 20 ft lbs.range. A2 at RC 60 is about 40 ft-lbs CPM 3V at RC58 is about 85 ft-lbs and drops to about 50 ft-lbs at RC 60 (see note below, 3V impact resistance may be somewhat lower than 50 at RC 60) Note the above was written to answer an e mail I received on knife blade toughness and how tough my knives are. This reply is about 6 years old as I write this in 2006. The only caveat I would make at this time is on 3V. I made several chopping type knives from this steel at RC 60/61. Pushed very hard cutting oak I got some edge chipping. When the blades were re-tempered and the hardness was reduced to 58 the chipping was not a problem. The only conclusion I can draw from this is that 3V toughness falls off quickly over about 59/60 Rockwell. This is my experience and may not bear true with other makers. In addition this is based on just a couple of knives since I do not use much 3V. If a user wants a “non” stainless blade I usually recommend 10V. Phil Toughness is a particular concern with high alloy tool steels at high Rockwell hardness. They have pretty good bending fracture strength but not so good impact resistance. I primarily use high alloy steels at a relatively high hardness because I am striving for the maximum in cutting and edge holding performance. To achieve that I am flat grinding blades to a very thin hard edge. The harder a blade is the higher the tensile and compressive strength it has. This is important on a thin edge because the stronger ( high tensile and compressive strength) the steel is the more is resists edge rollover… a common reason a blade gets dull. The problem is that--- the harder the blade is the less tough it is. So I am walking a fine line between hardness and toughness. A fine edge that is too brittle will get dull because it simply cracks away. Some tool steel companies will give you data on Charpy tests of the steels that correlate to Rockwell hardness. Crucible is particularly good at this. So if you know the Rockwell hardness then you have a pretty good idea of the impact resistance of the steel. The best of all worlds is to be able to select the best steel for the knife use application. I would select a steel formulated for high toughness (high Charpy impact resistance) for a large camp knife or a sword. Good choices would be A-2 ( 40 ft-lbs at RC 60) or CPM 3V (85 ft-lbs ? at RC 58) On the other hand the best selection for a slicing type knife would be a steel with a very high vanadium carbide content hardened to a high value-- at least 60. It would have a relatively low Charpy value, but that’s ok since we are looking for maximum edge strength and wear resistance rather than toughness. A good choice would be CPM S90V ( 19 ft-lbs at RC 58) I do my own heat treating and have a good Rockwell tester so can get very close to the line. In other words I make a very hard, thin blade that has enough toughness for a working blade. I make slicers (hunting and fishing scalpels) rather than choppers so it works out ok for me. I think the tool steel companies are very conservative with their Charpy values. Especially on the CPM grades. For example I have been making a lot of hunting blades out of CPM 10V. The data sheet from Crucible on this steel indicates that it has about the same toughness as D-2 at the same hardness. I have found that I can heat treat 10V to about Rockwell 63 and it still has more than adequate toughness for a working knife. My experience with D-2 in the past indicates that it starts to get pretty brittle at about Rockwell 60. I have also found with all the steels I am familiar with that toughness is very sensitive to heat treating. Good heat treating means a uniform crystal structure and as fine a grain structure as possible with any particular steel. Think about it. If you make a long bow out of a piece of wood that has a knot in it, that’s where it’s going to break-- and at a pretty low force. The same is true with steel. It’s going to fail where the imperfection is. I like to use a liquid nitrogen cryo quench right after the steel comes down to room temperature to insure the highest percentage of martensite possible and then to temper the blade a couple of times to develop adequate toughness but still retain a relatively high hardness.
Click to expand...

he also has LOTS of good articles listed here, including some on S30v, heat treating, sharpening etc.
http://www.seamountknifeworks.com/articles.htm


IE http://www.seamountknifeworks.com/articles/S30V.pdf
http://www.seamountknifeworks.com/articles/S30V_update.pdf

If you look at the S35vn pdf from crucible, it has even more impact resistance.
https://www.crucible.com/PDFs\DataSheets2010\dsS35VNrev12010.pdf
 
Last edited:
You must log in or register to reply here.
Back
Top