With all the focus on blade performance why no standardized cutting tests?

M

monkapotamus

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I'm a newbie to Blade Forums and find the topics fascinating. I've ordered several knives off of the manufacturer and vendor recommendations I've seen here. With that in mind with so many detail focused people here discussing blade composition and performance why are there no even semi-standardized cutting performance tests? Blade performance testing is largely ad-hoc and consists of hacking and slicing stuff around the house or yard and placing it along the continuum of "Wicked sharp!", "Sharp enough for me", or "Meh".

I realize it's convenient to use what's at hand, but if you really want to be able to say blade material X is superior or inferior to Y you might want some sort of consistent, repeatable metric that can compare real world cutting performance. Would designing a easy to obtain and assemble consistent gauntlet of materials to be cut, then measuring post-cutting sharpness be too difficult a task with all the talent available on this board?
 
Welcome to Blade Forums. If you dig around a bit and especially in forums like "Knife Reviews & testing" You can find folks that do consistent cutting performance tests on just about every steel that is offered.
 
Sharpness and edge retention are pretty easy to make generalizations about, they're very difficult to measure with any precision. To be really accurate you would need identical blades heated to the same RC, you'd need a variety of extremely consistent media to cut, you would really want repeated tests with fresh blades sharpened in an extremely consistent manner, tests done with the edges at a variety of different angles, the list goes on.

CATRA testing is the current standard and even it has it's flaws and is very expensive. I would love to see more objective testing, but one would need a ton of money to get it right.
 
singularity35 said:
There's CATRA but nobody really likes tests that don't uphold their prejudices...;)
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Of course. Manufacturers do their own testing, they aren't going to release result because you always have that one segment of special snowflakes that feel that they can do better or have some better way of doing something all while being hosted on Youtube. Don't get me wrong, some guys do a good job putting a knife through reasonable tasks, but then you have the obscenely demented folks that think smashing a locked folder with a sledge hammer is a "scientific test of strength and integrity" or some such nonsense.
 
As RetiredGuns says, some guys do have some pretty intensive tests that are standard at least across the board for their reviews.

But when you really get down to it, using what is available and decided if it's wicked sharp, decent enough or meh, is already a pretty good method.

If it cuts what you need it to cut to your satisfaction, there you have it. :thumbup:
 
Former ski instructor and now working engineer/scientist perspective.

As is the case with skiing, knife performance occurs at the 3-way intersection of: a) the knife's design, b) the user's skill and technique and c) the medium being cut (or skied). There are no meaningful single tests for knife blade performance for the same reasons there are not overall tests for ski performance - namely there is no meaningful way to standardize the user's skill/technique and no way to standardize the range of mediums to be cut (or skied).

Obvisouly, one can create standardized tests of various types by eliminating variables. Put the knife in a machine to make the same type of cut in the way every time. Cut the same medium every time. The CARTA test does this and many amateur rope cutting approaches do a similar thing. But, at best, these approaches can only say something about cutting similar materials in a similar manner. A knife optimized for CARTA tests (thin behind the edge) will not do well for wood working (thicker convex edge does better). A knife that does well cutting rope (like the Boye Cobalt Dendric knives) won't be the best kitchen knife.

A better engineering approach in complex situations such as this is to take a more clinical approach. Test a lot of sample by giving them to experts in a certain type of cutting (or skiing) situation and seek qualitative (not quantitative) feedback on them. One knife testing author (forget the name) was on the right track by recording the preferences among meat cutters - at least in so far as understanding steels and geometries that do well for meat processing.

Want to know the best slalom race skis? Watch the podium. Want to know the best powder skis? Ask the dirtbags sleeping in the back of their trucks in the parking lot (btdt). Want to know the best geometry or steels for bushcraft, or hunting, or construction jobs or whatever... ask the experienced knife guys who do a lot of that type of knife work.
 
You don't need a standardized test, you have everybody's opinion. There is no best knife, there are just a bunch of good useable knives. Steel can be made to perform, Proper heat treatment, good blade design, and proper honing does the trick. I just bought the latest greatest knife with a steel that I have never owned before based on Anderson's steel evaluation M390 . The knife will be a general use daily carry knife. I will also have a whittler in my pocket, because that is what I like to do, but i hate to just cut stuff with a blade that is scary sharp edge profiled to carve wood. You have already had some good responses although I do not ski. Decide what you want the knife too do and see what people who do what you want use and go buy it. While i was thinking about how to respond to your question, I also when and bought a Great Eastern knife, I don't have one and i am always looking for the perfect knife- even though I ALREADY KNOW IT JUST DOES NOT EXIST. But there are a lot of really nice knives, you just have to keep looking.
 
I've thought about this in order to determine a way to do some testing of my own but I haven't come up with anything.

After more thought I realized that it is a very difficult thing to test. Apparently even if you do it scientifically there is a lot of inconsistency in the results. So that along might make it difficult to rank steels. And then the performance depends on so many factors such as steel type, heat treat, blade shape, thickness, grind, sharpening angle, sharpening grit, and what you are cutting. Unless you have someone that will make you identical blades in different steels, there isn't a way to start the testing in equal fashion. The Spyderco Paramilitary 2 has been made in a range of steels so you could start there. You could also start with the Spyderco Mule series but not all of them are manufactured identically.

Also I have wondered if one steel would test well cutting one type of material but another steel would test better when cutting a different material.
 
RevDevil said:
Of course. Manufacturers do their own testing, they aren't going to release result because you always have that one segment of special snowflakes that feel that they can do better or have some better way of doing something all while being hosted on Youtube. Don't get me wrong, some guys do a good job putting a knife through reasonable tasks, but then you have the obscenely demented folks that think smashing a locked folder with a sledge hammer is a "scientific test of strength and integrity" or some such nonsense.
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Wait. WAIT!! What are you saying!?!?! Are you implying that those tests don't have real honest to god VALUE!?!?! Are YOU demented!?!?! :confused::rolleyes:

Sorry, I just couldn't resist. Joking aside, this is a cool thread and an interesting topic. I actually enjoy the tests with the over-the-top data analysis. I don't always understand them, but appreciate the data driven approach to determining who has the "best" steel.
 
The problem with any "standardized" testing is that it would not take into count what you wanted to do with said steel. A steel that is a very high carbide alloy would be great at cutting a "standardized" media. Great, but not truly tough. Now, change the game to a big, burly "camp chopper", and that same high carbide alloy would likely fail. Different steels for different jobs. Nothing is free with steel. 3v and Infi may excel at tough, burly, beater steel. Likely the toughest of the cutlery grade steels. Want to go tougher? Let's move to S7. That is literally jackhammer bit steel. Very tough, low edge retention. Want to cut a fibrous media? Let's get into S110v, or the A11 steels. They will cut circles around S7, but can't hold a candle to S7 in toughness.

Standardization is impossible. Different uses, different tools.
 
I think you could construct a jig or even robot that would perform precisely identical cuts, chops and slices in a variety of standardized materials - and you'd likely get results that still aren't very precise and appear to largely match up with the general semi-expert opinion of knife people.

I don't know what benefit would come from that enormous effort. Certainly a few favorites would be dethroned, some bargain surprises would come out and a little more knowledge on knife selection would be added to the mass that exists already.


BUT, knives - no matter how sophisticated - are essentially primitive parting tools, not fusion reactors or even all weather tires. They no longer perform an essential role in modern people's lives. Their absolute performance just isn't critical enough to make a science out of their evaluation.

Having a pet steel or favorite maker is ultimately more satisfying than selecting your hobby fixation off a standardized list.
 
Let's get real here, R2-D2 has it right. What modern man would need a knife for more than slicing cheese and smoked sausage for his weekly office party?

CPM-S90V and M390 (and their carpenter steel counterparts) are obviously the clear wieners. If they can cut rope all day with less than 20 psi and still shave body hair, their sharpness will clearly out live the universe when going through office food, without sharpening.

...not to mention they'll save the guys tons of money from waxing sessions and no!no! purchases.
 
jpm2 said:
Let's get real here, R2-D2 has it right. What modern man would need a knife for more than slicing cheese and smoked sausage for his weekly office party?

CPM-S90V and M390 (and their carpenter steel counterparts) are obviously the clear wieners. If they can cut rope all day with less than 20 psi and still shave body hair, their sharpness will clearly out live the universe when going through office food, without sharpening.

...not to mention they'll save the guys tons of money from waxing sessions and no!no! purchases.
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I know you're attempting levity, but no modern man requires "The Ultimate Cutting Device". We can and do quite well with 19th century steels forged and heat treated with 12th century knowledge. No one loses their job or goes hungry because they used an AUS-8 knife instead of an S90V one.

If you're requiring the finest cutting tool for eye surgery, it will likely not even be made of metal.


I like my D2 and S30V knives. I also like the 100 additional horse power my car has that I rarely access. It isn't about essentials, but love of minutia that applying too much science will destroy.
 
RX-79G said:
I know you're attempting levity, but no modern man requires "The Ultimate Cutting Device". We can and do quite well with 19th century steels forged and heat treated with 12th century knowledge. No one loses their job or goes hungry because they used an AUS-8 knife instead of an S90V one.

If you're requiring the finest cutting tool for eye surgery, it will likely not even be made of metal.


I like my D2 and S30V knives. I also like the 100 additional horse power my car has that I rarely access. It isn't about essentials, but love of minutia that applying too much science will destroy.
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You must have a mouse in your pocket...

I can do the job with the cheapest blade steel, but my clients ain't gonna like it when they're losing $100+ per minute and I have to stop work and repair my edge to finish the job.

for the record, Aus-8 and S90V doesn't hold up for my use, neither does ats-34, 154cm, 440c. I'll have a verdict on s30v when I get around to it, but ain't holding my breath. The only thing so far that passes my tests are M2 and CPM-M4.

I briefly had a D2 blade and liked it, but didn't get to really use it as I normally would due to the 4" blade, which is incompatible for my work. Sold it off but plan to get another that's more usable.
 
singularity35 said:
There's CATRA but nobody really likes tests that don't uphold their prejudices...;)
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Nobody likes tests that have little to no value. Some tests can give decent info but ultimately it comes down to trying the knife out for yourself on what you need to cut. No test can really tell what's going to work best for an individual. The "scientific" testing done by forum members I completely disregard. I see it as a hobby that some enjoy. There's no real data in them because they're horribly inconsistent. Different knife shapes with different steels with different HT's all being used by hand on inconsistent media...just bad testing protocol.
jpm2 said:
You must have a mouse in your pocket...

I can do the job with the cheapest blade steel, but my clients ain't gonna like it when they're losing $100+ per minute and I have to stop work and repair my edge to finish the job.

for the record, Aus-8 and S90V doesn't hold up for my use, neither does ats-34, 154cm, 440c. I'll have a verdict on s30v when I get around to it, but ain't holding my breath. The only thing so far that passes my tests are M2 and CPM-M4.

I briefly had a D2 blade and liked it, but didn't get to really use it as I normally would due to the 4" blade, which is incompatible for my work. Sold it off but plan to get another that's more usable.
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Gotta ask. What job do you have that you charge over 100 bucks a MINUTE to use a knife?
 
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Shotgun said:
Nobody likes tests that have little to no value. Some tests can give decent info but ultimately it comes down to trying the knife out for yourself on what you need to cut. No test can really tell what's going to work best for an individual. The "scientific" testing done by forum members I completely disregard. I see it as a hobby that some enjoy. There's no real data in them because they're horribly inconsistent. Different knife shapes with different steels with different HT's all being used by hand on inconsistent media...just bad testing protocol.


Gotta ask. What job do you have that you charge over 100 bucks a MINUTE to use a knife?
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What I said. ;)

singularity35 said:
There's CATRA but nobody really likes tests that don't uphold their prejudices...;)
Click to expand...
 
The issue with CARTA isn't that it challenges some folks prejudices. It's that it applies to a single type of medium being cut and a single type of cutting action. The test is meaningful only in so far as that medium and that cutting movement correlate to a particular user's situation. The automotive equivalent would be the 1/4 drag race as a standardized performance test for cars. It's definitive only in so far as drag racing matches the kind of driving you do. The 1/4 miles tells us little about the overall performance for closed circuit GT racing and CARTA tells us little about, say, wood working performance.

Please see this white paper from Crucible Industries.
http://www.crucible.com/pdfs/SelectorKnifePocketRotatedCrucibleLLC.pdf

In particular, please see the "Experienced Based Measures" table at the bottom. "Experience Based Measures" means something along the lines of qualitative analysis from input by qualified experts; which is to say, something along the lines of seeking input on the different handling and performance characteristics of GT racers from qualified racers.

Crucible is doing really excellent performance engineering in presenting this sort of table and it's exactly why there is no single objective test for selecting knife steels. Horses for courses.

Note, this doesn't mean that CARTA (or hobbyist level rope cutting) is utterly meaningless. Just that it illuminates a very narrow aspect of knife blade performance and, depending on the use case under discussion, may be entirely irrelevant or over come by other more dominant factors.
 
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