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CATRA Results

Posted by CliffStamp 
CATRA Results
June 09, 2012 06:15PM
I have been collecting CATRA results : [www.cliffstamp.com]

A few points to note :

-CATRA is very sensitive to blade geometry because it is method which combines cutting ability and sharpness into one measurement. This means that you can easily make for example 420J2 out perform S115V on a CATRA simply by grinding the 420J2 thinner at the edge. Because CATRA is a machine cut there is little lateral loading so the edges can be extremely thin and not collapse.

-As the knives from different sources are not identical in shape they can not be compared directly, they just have to be loaded into the data pool and at best can be used for rough relative qualitative comparisons.

-Basically CATRA is a heavy wear test so the knives will simply end up being ranked in carbide volume, and the knives with a high MC carbide volume in particular (high Vanadium / Tungsten grades) will tend to dominate

If anyone knows of other results let me know so I can collect them. I will eventually add some commentary to this page but for now it is a plain table only. There are some fairly interesting results though if you look at the differences between the same steel in different CATRA results.
Re: CATRA Results
June 10, 2012 01:52AM
I wonder if they don't regrind the knives for the same reason you get so much flak for. You're often called out that you "make knives fail" because you regrind them, so if they did it to they could be called out for tampering with the results. Although by logic the realistic results should be seen if every knife tested had the same geometry and every edge the same level of finish.
Re: CATRA Results
June 10, 2012 07:50AM
Could be that they are testing as sold. R&D teams probably try all kinds of stuff, most of it will never reach the market.Catra result would be misleading if you do anything other then the knife as sold, and don't thoroughly explain the context and even then...
Re: CATRA Results
June 10, 2012 07:57AM
That's true
Re: CATRA Results
June 10, 2012 01:19PM
When you submit blades for testing you can request they be sharpened or you can provide them sharpened. I don't think you can send them a bar and ask them to make blanks from it and that is the part which causes much of the confusion as Spyderco, Dozier, etc. they all use different blanks. The curious part is that some of the numbers agree but some of them do not. Look at for example Dozier vs Spyderco on S30V vs S90 V. Both of them agree on the performance of S30V but Dozier has S90V 50% higher than Spyderco does - that is a bit curious as you would assume they used the same blanks for both steels.

I added a relative scale column and add some company numbers from Latrobe, Crucible, etc. . as well.
Re: CATRA Results
June 10, 2012 01:56PM
I'm surprised a bit that VG-10 went over 154CM. Not by a significant amount but this goes to show that all the talk about 154CM always outperforming VG-10 can't exactly be trusted.
Re: CATRA Results
June 10, 2012 05:35PM
154CM and ATS-34 are the same steels, just different manufacturers so the expected properties would be the same. Note that there is a fair amount of drift about VG-10 from the number of points on ATS/154. As a general rule, there is no reason to expect VG-10 to be significantly superior to ATS-34 / 154CM as it is just that steel with the Molybdenum reduced and Cobalt added. The main promotion of Cobalt (in that type of steel) is to solid strengthen the matrix and reduce carbide tear out.

The other influence is that VG-10 doesn't have the hot hardness of ATS-34 as that comes from the Molybdenum, but for knives that isn't useful outside of how it is hardened. ATS-34 / 154CM was traditionally hardened using the secondary hardening of a high temper, but that stopped years back when a number of users started putting forth data showing that the secondary hardening point (which was promoted by many including Paul Bos) produced inferior results (lower toughness, corrosion resistance, etc.). Knife maker Ernest Mayer was one of the first to argue in public that Bos was wrong and that a lower temper is more optimal.
me2
Re: CATRA Results
June 10, 2012 07:50PM
I'll bet that went over like a turd in the punch bowl, even though nearly every generic discussion of martensitic stainless steels I've read mentions it. eye rolling smiley
Re: CATRA Results
June 10, 2012 08:15PM
As you would expect, it was ignored, then it was met with near mockery with the daring to imply Bos was wrong. Ironically Mayer stopping knives before seeing almost everyone, including Bos, switched to the low tempering. No acknowledgment of course about the fact they were no only wrong, they had made a practice of outright mocking anyone to even imply such. 3V I believe is one of the few steels which still uses a high temper.
Re: CATRA Results
June 11, 2012 01:24AM
That is a shame. In my head 154CM was always somehow close to s30v, and above VG-10 and AUS-8.
Maybe It's primarily due to me coming really into the knife world at the time when BM Grip was the knife to beat and Paramilitary started to challenge it's dominance. I think it was in 2008, although both knives were out longer from what I remember. It could also be due to the boom of YT reviewers that happened.
Re: CATRA Results
June 11, 2012 08:20PM
It is very close, these results can be very misleading as they are only indicative of comparisons of very blunt blades as the CATRA results are on blades used to the point they are very dull. If you sharpen when you start to see the blade slip, or even don't keep careful records you will never notice a difference in S30V and 154CM as even small differences in geometry/finish can easily be larger than that steel difference.
Re: CATRA Results
June 12, 2012 02:04AM
Guess then I was closer to the truth than I thought. With me asking all these questions recently, do you feel like some kind of an old sensei? lol
Re: CATRA Results
June 12, 2012 10:50AM
I ask just as many questions. Never be afraid to ask, the worst than can happen is that someone thinks you are a bit of an idiot and as Feynman was fond of noting, and eventually tiled a book - what do you care what other people think? You can't learn if you don't ask.
Re: CATRA Results
June 12, 2012 01:11PM
Oh, I've studied the topic of Feynman's brilliance. That's what prompted me to ask as many questions as possible
Re: CATRA Results
June 18, 2012 10:12AM
I was speaking to Roger at CATRA trying to sort out what is going on with the results where some manufactures report results way higher than another for the same steel. I figured what may be happening is that some people are just running the machine longer to report a higher TCC count. I confirmed this indeed with Roger, when a CATRA run is requested you can ask for a specific cut length. This means for example if you want to claim that you have a special HT which raises the performance of S30V, all you have to do is ask for a cut length of 80 cycles (the standard is 60) and presto your S30V TCC will be higher than the standard. This just shows you one of the problems with "lab" results and hidden variables.

I am in the process now of contacting all of the people who post such results and trying to find out the cycle length they have used.

Dozier : [www.dozierknives.com]

Spyderco : [www.spyderco.com]



Edited 2 time(s). Last edit at 06/18/2012 11:23AM by CliffStamp.
Re: CATRA Results
June 18, 2012 12:46PM
Great, simply great
Re: CATRA Results
June 19, 2012 08:01PM
Dozier has confirmed it was 60 cycles.

I was speaking to CATRA and they noted a further problem, samples sent in for testing often have such poor initial sharpness or burnt edges so that the TCC value is subject to extreme inconsistency. The effect of this one variable is in fact greater than the difference between 420J2 and ZDP-189. Further people only pay for one test so there is no measure of stability.

In short, take extreme care in using the reported CATRA data to estimate performance - does this strike anyone as extremely ironic.

CATRA actually provides much more information than the TCC, the other two critical factors are initial sharpness and a factor they calculate (the initial drop in edge retention) which has a pass/fail to indicate burnt edges. They provide these and the full graphs to anyone requesting the testing.

It costs $80 for a test so it isn't cheap, especially if you wanted multiple runs or at least two to compare your sharpening to theirs (plus shipping).
Re: CATRA Results
June 20, 2012 02:22AM
Yes and I saw ppl giving you jackass answers on Spyderco Forum. Gotta love fanboys
Re: CATRA Results
June 20, 2012 06:24PM
Spyderco has confirmed they use 60 cycles, I have tracked down who I need to talk to at Bohler, Pat Miller who does all the work with the knife industry. I will be speaking to her shortly. Bohler have also hinted at new steels in development and that samples are available for knives. I will discuss this with Pat and see what can be obtained, ideally get some small pieces which are pre-hardened sensibly and see what we can come up with for some proto-types to bang around.
Re: CATRA Results
June 20, 2012 10:37PM
It would be very slimmy to request more cycles and then promote it as being better. Hopefully no one is pulling that bs.
Re: CATRA Results
June 21, 2012 05:20AM
To be perfectly honest, I am not sure they really give it a lot of thought. If you look at the results and talk to people it is almost treated like magic at times. For example one of the most telling things was when Buck did two experiments :

1) They ground a knife out of 420HC and one out of BG-42 and left the angle on the 420HC much smaller

2) They tested a blade with a hard coating on one side (Ion Fusion)

Now the results of these should be obvious to anyone who understands what CATRA does but they were certainly a surprise to Buck which indicated they really did not understand the numbers that the CATRA machine produces.

Note that that CATRA machine uses a specific load force and produces a TCC number based on how many cards are cut under that load by making 60 cuts, well obviously if you grind an edge thinner it will cut more per load regardless of the steel being used.

Similar as the CATRA machine is so tightly controlled and eliminates side loading, the steel wore off the side of the Ion Fusion coated blades and the little strip of coating could cut without folding - but this is totally unrealistic to think it could apply to people using it.
Re: CATRA Results
June 21, 2012 10:43AM
Good that Sypderco confirmed that. Do you need a secretary? I'm looking for a job, and I'll even shave my legs lol
Re: CATRA Results
June 22, 2012 09:50AM
I was talking to Hamby again, look at this : [www.catra.org]



You can see a difference of 15:1 in terms of edge holding. They attribute this mainly to poor initial sharpness. I can verify this is true even in the inexpensive run I am doing as some of them come with very poor edges with a large burr and it will collapse and go dull extremely fast. This is the main reason why the expensive kitchen knives have so much better edge retention - they just come sharper.

They can normalize this effect out if you just ask them to test it with the edge they get from their sharpening machine, however the knife companies in general do not do that, this they feel is likely the main reason for some steels being so difference from one claim to the next, the knife was just that much sharper.
me2
Re: CATRA Results
October 21, 2012 01:23PM
Digging through some old threads looking for something. Does the initial blunting calculation indicate the speed of loss of high sharpness, or just an indication of whether the edge was poorly sharpened/burned? I am and have typically been interested in the quickness of loss of the high sharpness, and have found the Byrd knives steel and even Cold Steels Krupp stainless can keep up with S30V to a point. I hope to repeat these, just using Krupp and S30V from Benchmade. These are rough relative performance estimates, as I did not repeat the cutting. In any case, the only steel completely outclassed was the annealed 1095 blade in the group of 1095A(nnealed), 13Cr4V (Byrd), Krupp (Cold Steel Kudu), and S30V (Benchmade). This similarity in the initial loss of high sharpness is the reason I see no need for the high carbide/wear steels. When the knife starts to drag a little, I sharpen it. I'm just wasting steel keeping that high sharpness on blades that one might say are not intended for that king of use.

On another point, is it safe to say that differences in sharpening could be the sole determining factor in whether someone has a good or bad experience with a give steel type? Say one user is an experienced sharpener, and takes care to eliminate the burr and refine the edge on a blade of 12C27 and another user is sharpening a blade of lets say S35VN and uses no deburring steps with stones and relies on stropping on green loaded leather to remove the burr (which I don't think it actually will btw).
Re: CATRA Results
October 21, 2012 02:55PM
Quote
me2
Does the initial blunting calculation indicate the speed of loss of high sharpness, or just an indication of whether the edge was poorly sharpened/burned?

The rate of loss of sharpness is highly nonlinear and will always have a high initial rate (relative) because of the fundamental physics involved. However the rate is severely effected if the edge is burnt or initial sharpness is less than ideal.

Quote


This similarity in the initial loss of high sharpness is the reason I see no need for the high carbide/wear steels.

Landes was the first one I saw openly challenge that the low carbide steels can in fact have superior initial edge retention, but only when they have the required HT to maximize hardness, minimize retained austenite, and have the required pre-HT conditions to ensure a well distributed alloy content (proper rolling and normalizing). But even if this isn't done, there is no advantage to high carbide steels until the edge has thickened to the point that the carbides are stabilized. At this point the difference starts to become dramatic and can be multiple to one easily, but this level of sharpness is pretty low, long past the point where anyone who can sharpen would achieve even by accident on a stone. If for example you just have a diamond rod and would give a knife a periodic pass then high carbide steels are not relevant.

Quote

Say one user is an experienced sharpener, and takes care to eliminate the burr and refine the edge on a blade of 12C27 and another user is sharpening a blade of lets say S35VN and uses no deburring steps with stones and relies on stropping on green loaded leather to remove the burr (which I don't think it actually will btw).

The difference that initial sharpness makes is easily 10X and that is just my personal experience of when I really focus to ensure proper sharpness to when I get a little sloppy. Even at worst the edge would always easily slice newsprint at the start. I really only noticed how much of an effect this made when I started measuring initial sharpness and saw just how dramatic it was when you really minimized the burr after taking care to remove weakened metal in the first place. The other thing here is that the low carbide steels are also much easier to get sharp in the first place.

But again lots of people don't have this view and for them a VG-10 blade makes perfect sense in the kitchen as they will use it to the point it won't cut anything where I will sharpen as soon as it starts to skid and has one dead pass. Even then this is months and only a couple of minutes for a full sharpening, not stropping, full edge reset and finish.
Re: CATRA Results
December 03, 2012 02:47PM
Updated with H1 and X15 TN from Benchmade.
Re: CATRA Results
December 03, 2012 04:22PM
Cliff,

Quote

Landes was the first one I saw openly challenge that the low carbide steels can in fact have superior initial edge retention, but only when they have the required HT to maximize hardness, minimize retained austenite, and have the required pre-HT conditions to ensure a well distributed alloy content (proper rolling and normalizing). But even if this isn't done, there is no advantage to high carbide steels until the edge has thickened to the point that the carbides are stabilized. At this point the difference starts to become dramatic and can be multiple to one easily, but this level of sharpness is pretty low, long past the point where anyone who can sharpen would achieve even by accident on a stone. If for example you just have a diamond rod and would give a knife a periodic pass then high carbide steels are not relevant.

All very true, but my perception is that we are missing the point behind high carbide stainless steels:

1. With stainless steels, it is very difficult to obtain reasonably high hardness without rising the carbon content and along the way the carbide fraction volume. This is because the high affinity that chromium and other alloying elements have for carbon. As I see it, for knives, the presence of >1u carbides are pretty much an unwanted side effect.

2. The bulk of the stainless tool steels were primarily developed for high wear industrial applications and the fact that they are also used for knives is simply a matter of lack of alternatives, rather than optimal suitability.

3. The cutlery marketing departments have made a virtue out of an evil necessity, that of carbides! Metallurgy is a difficult science to understand and the market has simply been duped by the misrepresentation that since carbides are very hard, lots of large chunks will somehow enhance the edge holding of knives, where in fact the opposite is true, because of the edge destabilizing effect.

Cheers
John
Re: CATRA Results
December 03, 2012 05:36PM
John,

The metallurgy of hardness/hardening in stainless steels is a long ago solved problem in any metallurgy text. Most of what is read/posted by makers/manufactures grossly exaggerates the complexity as to make it sound like they are working on a difficult problem. In reality you can simply look up the C/Cr isotherm for stainless steel, even the C/Cr/Mo isotherms, and from that and the tie lines it is known at the soak temperature what percentage will be in solution. It thus can be determined for example that in 440A stainless, with an optimal soak, 0.48% of carbon is in solution and thus a maximum hardness of 60 HRC can be obtained. To increase the hardness the C/Cr ratio simply has to be adjusted to move it down an onto a tie line which intersects the carbon saturation line at the desired point. AEB-L for example does so and creates a maximum hardness of 64 HRC. If this is desired to be increased then then soak temperature of 2015 F would have to simply be increased and to prevent grain growth one would have to flash soak, i.e., friction stir processing, induction hardening, etc. .

Note the high carbide steels actually decrease the hardness usually because they are not balanced to produce hardness but they are created to produce a large volume of primary carbides and thus they are very far to the right of the carbon saturation line. As noted, this is because for the purposes they are created, a high wear resistance is required. But again in the tool industry, this isn't a difficult problem, the steels used for knives never have a high primary carbide aggregate as this doesn't assist edge retention at high sharpness. Steels designed for retaining a high sharpness are steels such as the F series, the tungsten grades, the white/blue series, etc. . However there is a very curious thing which happened in the cutlery specific industry which I have never seen anyone explain, or even source how it happened.

If you read books from some time ago and look at the edge angles they are all very low, even axes have very low angles. As a specific example, in Cook's book (1921) you will see the edge angles of a swamper axe at 17.5 dps. If you scan modern small folders, 17.5 dpi would be considered a low angle - however this is a full size swamping axe, and these were the utility axes used to cut limbs roots, etc. which were ground with steep angles because they were not meant to cut well, but be durable. A full size felling axe would be ground to 15 dps, and again this is a full size felling axe swung by able bodied men and slamming into traditional NA woods. Note as well that this was the final apex angle, it quickly swept back into a lower angle to provide relief. When I started years ago writing about edge angles on chopping knives in the 8-10 dps range and 12-14 micro-bevels I received quite a lot of flak as this was quite in opposite to current convention thinking. The reason this happened is because now the steels used on all knives, even large ones are extremely idiotic choices in general. They are ultra brittle, extremely high carbide steels which have forced the more than doubling of edge angles on cutlery.

Now why did it happen? I believe what happened was a slow erosion of skills, people no longer know how to use knives, a complete passivity of sharpening (most don't do it), and thus a move towards using materials which while not working well at a high sharpness, do work very well at a low sharpness as once very large angles are used and once a tolerance for very low sharpness is acceptable - then the solution is no longer F2 it is D7 . Now there is nothing wrong with this inherently, and in fact it is fairly idiotic to try to convince someone who isn't going to sharpen knives and uses them as scrapers and bangs them around in the kitchen sink to buy an AEB-L knife. Get them a 440C knife and set the edge at 0.020"/20 dps and they will be happy much more than a 0.005"/10 dps AEB-L knife. Now as a knife maker/manufacturer do you make your knives for the ten people who are suited by the former or the one guy suited by the latter?

The thing is though that the market is starting to shift again, have a look at the marketing by Shun which constantly promotes the low angles, high sharpness, high cutting ability and non-tool aspect of their knives. The real curious question is will be go all the way back to the 1920's when knives where made well when they cut well, were easy to sharpen and could maintain a very high sharpness or will we end up settling into a middle ground punctuated by all kinds of outliers for various small groups. Of course all of this is mainly the NA market, if you look at the Japanese market there has been no such wild changes, the knives are still made out of F2 class steels, ground at low angles and kept very sharp. I don't believe the French market has been so dominated by the high carbide / low edge angle trend either, Mad would know more.
me2
Re: CATRA Results
December 04, 2012 05:54AM
The only modern text Ive read which addresses such low angles is Lees book on sharpening. Aftrr reading his book, and presuming he and his family knew how to use an axe I began wondering why anyone would advocate a 25+ dps angle on a folder of any size. However, look at the high end tacical folder market and there they are. The thing that really irritates me is that people dont understand why I make a comparison between my large choppers with foot long blades and edge angles nearly half that of a 3" blade folder.
Re: CATRA Results
December 04, 2012 01:29PM
For reference and some understanding : [www.spyderco.com]

Relevant quote :

Quote
Chrottos
As many of you know, the Byrd line is manufactured overseas and uses the softer 8Cr13MoV steel. The only problem I have with the Meadowlark is edge retention when being hair-whittling sharp. After cutting just a couple strips of cardboard, the sharpness would suddenly be sub-shaving.

Note the common responses to :

-switch to a "better" steel
-increase edge angle
-do MOAR stropping

Now stop and think for a minute, if you are cutting just a few strips of cardboard and the knife goes from hair whittling to below shaving, are these solutions sensible, especially the first which is completely ridiculous if you consider a percentage gain.

Now if you accept that the people on that board are above average in knowledge on knives (this is certainly true) how come so few realized that it is simply a sharpening problem, not a steel, angle, etc. one - and certainly not one that would benefit from stropping as that is known to cause it.

If you are advocating 15+ edges on a knife then you are either :

-using it as a cold chisel
-have a really insensible steel choice

-or-

-don't know what you are talking about
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