Oct 2010 Knives Illustrated CATRA results for six Crucible steels

[The Mastiff]

I am really disappointed. I suspected that CPM S30V is not better then CPM S60V, but did not expect such a difference in CATRA edge holding tests recently reported.

Vassili.

As I stated before S90 was the replacement for S60V. S30V wasn't, and is in what could be called a different category. In addition, you seem to have missed that they ran the S60V way higher for this test than they would/could have on a production knife blade due to it's often discussed and well known problems. A much more realistic hardness level for S60V would have been in the RC 56 to 58 range, where it had other problems caused by the low hardness numbers such as rolling due to lack of strength.

This was known long ago. I recall reading a TK magazine where the steel ( then called T440V) was introduced on the Millie. Already, back then it was known that S60V probably wasn't the answer, and that S90V ( then called 420V) was more appropriate due to the ability to run it harder without chipping , or rolling at the lower RC's needed to keep s60v intact. These unrealisticly high hardness numbers undoubtedly added to the CATRA numbers recorded here. I very much doubt that the average RC 56-57 S60V would have recorded the numbers shown above.

S30V did come out much later but, if some in the business are to be believed, as a stainless version of 3V. I have no idea if that's true or not.

S30V is generally acknowledged to be a good steel, but difficult and fairly expensive to make knives out of. As a stainless 3V it might be called a failure but that's subjective and not meant to be called a failure as a premium steel.

S90V and others in it's class ( ZDP, etc. )are generally referred to as super premium steels.

 

[Jason B.]

Correct me if I'm wrong but didn't Sal once say S90V and ZDP both scored a 750 on a CATRA machine?

 

[hardheart]

http://www.spiderco.com/forums/showthread.php?p=573359

A lot can affect the results though. The speed, length of cut, and cutting force can be adjusted, so maybe those aren't the same between tests. Then of course we don't know what the difference in hardness is between the test pieces. And the things we have seen first hand that change cutting force (which is what the test is based on, the blades cut at a constant force until too dull to do so) edge thickness, angle, and polish.

 

[unit]

This is very interesting. I wonder how many people will select a blade steel based on this and nothing else though?

Personally I do not cut all that much cardboard, but I enjoy data of any sort. There is little doubt that this testing was done with exceptionally high control compared to many of the tests we typically see presented. Still, I think there is a lot to be said for the testing a guy does him/herself in his/her own environment with blades he/she has put an edge on.

You can say what you want about a person's ability to sharpen, but at the end of the day, the edge he/she is able to maintain is all that matters.

 

[DennisStrickland]

ditto to unit on the end of day comment. many individuals are'nt capable enough to put an edge on zdp at 64 or 3v at 60. the required usage & ability to maintain the knife to apply that knife as a useful tool in one's daily life is all that's really significant. we formites have a large percentage of us whom really like our knives to not only cut extremely well but also to continue cutting for a very long time. we sometimes forget the average hunter, worker,& kat walking are quite happy with 1095 @ 55 r.r.

 

[Broos]

Thanks for posting the edge dimensions, Hardheart. Unequal widths complicates the comparisons, and now we must speculate on how they would affect the test.

I agree that sharpenability can trump pure edge retention. It all depends on what qualities you want for a knife - ease of sharpening, ability to take a fine edge, & toughness all have their place in the logic to decide which steel you want for a particular knife or use. And all of them put together cannot save an ugly knife sometimes! I love the boutique performance steels, but actually only shoot one deer at a time (and then have a year or so to get it sharp again), so having a knife that can gut and skin 6 deer without needing to be resharpened is less of an advantage than me just knowing this is some bad a$$ steel!

For checking a steel's edge retention, the CATRA test is king. I suspect that we would have to come up with a funky test or unusual cutting media to be able to turn around the order of good CATRA testing - for slicing or push cutting. You can make a case that wear resistance is very important to push cutting tests also. What quality of the steel is important to resist edge roll - imo it is strength. Assuming the initial test edge is of sufficient width and angle to not fold over on the first cut, then what happens over time with cutting to allow the edge to fold? Isn't abrasive wear of the bevel weakening the edge a good candidate for this? So wear resistance would play an important role in push cutting wear in that scenario (which may be full of crap). I almost think that if you see an edge fold with a slicing or push cutting edge retention test, you are probably pushing that particular steel too far with the intitial angle or edge thickness. A chopping test is a good test to test for edge rolling, imo.

It would be interesting to see the same blades get tested with some changes - running the velocity as slow as possible, increasing the force of the cut, and/or changing to cutting manilla rope, and then compare the results again. It would be interesting to have a CATRA machine for our knifenerdly entertainment.

 

[hardheart]

I was a little hesitant to post the thicknesses because the article suggests that the measurements were taken after the CATRA testing was done. The blades were sharpened again by the author on a Lansky, at the 17 degree setting. I don't know if the measurements were taken before of after the sharpening, and the 154CM was sharpened more than the others because it didn't get as sharp off the fine diamond stone. This is also why I've left off the cardboard cutting impressions the author gave.

 

[Any Cal.]

This is very interesting. I wonder how many people will select a blade steel based on this and nothing else though?

Personally I do not cut all that much cardboard, but I enjoy data of any sort. There is little doubt that this testing was done with exceptionally high control compared to many of the tests we typically see presented. Still, I think there is a lot to be said for the testing a guy does him/herself in his/her own environment with blades he/she has put an edge on.

You can say what you want about a person's ability to sharpen, but at the end of the day, the edge he/she is able to maintain is all that matters.

Well said. And it was *this* close to becoming a sig line.

 

[Vorpal Blade]

here are the edge thickness at the top of the bevels

154CM-.008
S30V-.018
3V-.016
S60V-.013
S90V-.014
10V-.013

Too bad they can't all be the same.

The 154CM is the most significantly different and also the lowest performer. I don't know if that correlates to any other testing results. S30V next deviates the most from the average (.01367) but on the high side, and performed closest to 154CM.

If bevel measurements for each blade were the same, there would be one less factor of uncertainty.

 

[RJ Martin]

So the S30V blade edge was almost 30% thicker than the S90V edge.

I think that may have dimished it's relative performance. Actually, I'd bet money that it did.

The higher performers, like S90V and 10V, do not surprise me. They are both a bear to work, and a bear to sharpen. They should (and do) hold an edge a long time.

That S30V is better than 154CM also does not surprise me. You can mirror finish CPm154Cm easily. Not so with S30V, because of the Vanadium.

So, I agree with the rankings, but not on an absolute comparison based on measured # of cuts.

 

[lonepine]

6. We've always shared our findings with our customers as to our results. We just don't quote numbers.

sal

Mr Glesser: Thanks for sharing your experience with us. CARTA Testing a single blade doesn't represent how all blades of a given material will perform. How the steel is heat treated as well as the various blade profiles, grind angles, etc would all play a part in performance. And as you pointed out, CARTA testing won't tell you if the blade will break if dropped on the floor. (Real world testing?)

- Paul Meske, Sun Prairie, Wisconsin