Hardness vs Wear Resistance?

[nozh2002]

But it is because we have been down this road before and more than once.

The way that I do it is not going to change, you do it your way and that's fine.

The reason I won't change it is because of the accuracy that I can get and the level of accuracy and it's repeatable over and over.

When things are that accurate and repeatable there is no reason to change.

If it's not broke don't fix it.

OK! I though you were talking about making it constructive. But you going this road again - just ignoring whatever I told you. I am start thinking that you do not actually understand what I sad about placement and force of base impacting edge.

Sorry, you are doing your show, fine you have you "voters" and help knife industry with overstock of overpriced underperformed steels, but do not expect me to consider you opinion as something worse to pay attention.

Thanks, Vassili.

 

[Noctis3880]

OK! I though you were talking about making it constructive. But you going this road again - just ignoring whatever I told you. I am start thinking that you do not actually understand what I sad about placement and force of base impacting edge.

Sorry, you are doing your show, fine you have you "voters" and help knife industry with overstock of overpriced underperformed steels, but do not expect me to consider you opinion as something worse to pay attention.

Thanks, Vassili.

Nobody expects anything from you. So please stop expecting everyone else to follow your exact methods. It's just bureaucratic.

 

[Ditch_Digger]

OK! I though you were talking about making it constructive. But you going this road again - just ignoring whatever I told you. I am start thinking that you do not actually understand what I sad about placement and force of base impacting edge.

Sorry, you are doing your show, fine you have you "voters" and help knife industry with overstock of overpriced underperformed steels, but do not expect me to consider you opinion as something worse to pay attention.

Thanks, Vassili.

Vassili,
Jim's test results coincide with mine and many others here. If there's any burden of proof, it is on YOUR END. You are the only one that seems to have these "discrepancies" in your results! Do you seriously think that by simply adding a kerf/relief in the board he is cutting against, his test results will suddenly be reversed???

 

[Gator97]

...just ignoring whatever I told you.

Said Vassilli who ignores 100% of everything...

 

[cziv]

It seems to me that Ditch_Digger and nozh2002 are in agreement about using machines or "mechanical means" to eliminate the human element - with nozh2002 having an emphasis on eliminating an object to support what is being cut?

Sounds like you guys are really passionate about one thing. Finding the truth about steels and their cutting abilities/properties using as close to repeatable processes as you can do, like pure scientific research. Science = a search for truth right?

Good stuff. I wish I could understand you better nozh2002 but that's not your problem I suppose, just a very heavy accent that carries over into your writing.

 

[Jason B.]

I have a solution..... free hanging rope cuts.

Make a spring loaded swing arm that can hold the blades and make the cut. Put accelerometers on the blade and measure the resistance spike when the knife contacts the rope. I'd call that accurate

 

[hardheart]

get to the bottom of why his results differ so much from yours!

different knives, different manufacturers, different population of steels, different rope, different environmental conditions, different test parameters, different performance measures, different edge finishes, different sharpening media, different edge angles, different cutting methods, different people cutting

CATRA, with one machine model, testing one type of media manufactured specific to the purpose of testing, utilizing a developed ISO standard, with high precision in applied force, length and speed of cutting stroke, and much better resolution on measurements... still has measurements skewed by temperature and humidity affecting the test media. The same steel will produce different results depending on who produced the test blade, and to what geometry. In two separate tests, the same steel outperformed itself by 67% on the CATRA in wholly separate tests, and mostly because the test blades were made by two different companies. Buck made 420HC outperform BG42 by testing at two different edge conditions.

IMO, none of the independent tests are at all comparable due to the overwhelming number of variables that do not resolve.

 

[Bill1170]

To really tell us categorically, the ideal edge retention test would need to remove all the variables except for blade steel. That is really hard to do! Even blade steel varies by heat treat and sometimes by batch, due to impurities.

CATRA machine eliminates some variables.

Series of identical blades (in different steels) eliminates some more variables.

Testing in a vacuum eliminates atmospheric variations.

Temperature must be controlled.

Test media needs to be always the same.

More I did not think of already.


In the absence of this sort of rigor, the real world tests conducted by the likes of Jim Ankerson and Phil Wilson can still tell us a lot. I appreciate the efforts of sincere amateur experimenters everywhere. They work for free and publish their results.

 

[Ankerson]

In two separate tests, the same steel outperformed itself by 67% on the CATRA in wholly separate tests, and mostly because the test blades were made by two different companies. Buck made 420HC outperform BG42 by testing at two different edge conditions.

Yes, that is very possible, if the blades are not the same Hardness that a lone will make a large difference. Change the angle if the edge that will make a large difference. Change the edge refinement and that will make a large difference. If the blade grinds are a lot different that will make a large difference.

The difference in performance between a production blade and Custom in M390 was 210% with all the differences in RC hardness, blade grind etc. That's just one extreme example of how different things can be.

Another one with 2 ELMAX blades, difference of 210% in performance between a Production and Custom, differences in hardness ect like above.

 

[Folderguy]

Well, I am doing tests for 5 years:

http://playground.sun.com/~vasya/Manila-Rope-Results.html

Thanks, Vassili.

P.S. How sharpness is measured - http://www.youtube.com/user/nozh2002?feature=mhum#p/u/50/1Ftbus7LbtU

That's very interesting. Thanks.

 

[Folderguy]

OK! I though you were talking about making it constructive. But you going this road again - just ignoring whatever I told you. I am start thinking that you do not actually understand what I sad about placement and force of base impacting edge.

Sorry, you are doing your show, fine you have you "voters" and help knife industry with overstock of overpriced underperformed steels, but do not expect me to consider you opinion as something worse to pay attention.

Thanks, Vassili.

Sir, you just dissed Ankerson. Not smart, IMHO.

Perhaps you don't understand what he has written about his testing technique, as apparently English is not your mother tongue.

I find his testing to be helpful and relevant. About your setup, it was interesting to see how you do it. For my part, I think Ankerson's tests more closely approach a common sense way to evaluate edges.

To each his own.

One thing I will say regarding your dissing of Ankerson and the dismissive way you did it is that my respect for your testing and thought processes just went way down.

 

[Folderguy]

Nobody expects anything from you. So please stop expecting everyone else to follow your exact methods. It's just bureaucratic.

Bureaucratic, huh? I'd have a few choice words about it, but that might get into political considerations, so I'll refrain, at least for now.

 

[Folderguy]

I have a solution..... free hanging rope cuts.

Make a spring loaded swing arm that can hold the blades and make the cut. Put accelerometers on the blade and measure the resistance spike when the knife contacts the rope. I'd call that accurate

Hey, I like that! Kinda like the Cold Steel guys cutting free hanging rope, yeah! :thumbup:

 

[Folderguy]

different knives, different manufacturers, different population of steels, different rope, different environmental conditions, different test parameters, different performance measures, different edge finishes, different sharpening media, different edge angles, different cutting methods, different people cutting

CATRA, with one machine model, testing one type of media manufactured specific to the purpose of testing, utilizing a developed ISO standard, with high precision in applied force, length and speed of cutting stroke, and much better resolution on measurements... still has measurements skewed by temperature and humidity affecting the test media. The same steel will produce different results depending on who produced the test blade, and to what geometry. In two separate tests, the same steel outperformed itself by 67% on the CATRA in wholly separate tests, and mostly because the test blades were made by two different companies. Buck made 420HC outperform BG42 by testing at two different edge conditions.

IMO, none of the independent tests are at all comparable due to the overwhelming number of variables that do not resolve.

Excellent, clarifying post.

After reading your explanations, it's obvious why test results can vary as must as they apparently do.

 

[Ultimate]

ELMAX is in the list, it was the 0551 and it tested at 60 RC.

The custom I tested was at 62 RC and I didn't add that data, nor the Customs in M390 (62) and CPM-10V (64.5 RC). They are all way off the scale performance wise, the difference is huge.

What method do you use to test Rockwell hardness? Do you have a Rockwell hardness tester? I find it hard to believe that you spent a minimum of $1000 on an accurate hardness tester...

I would also like to see a series of photos or video of your experiment set-up and process. Just a few pictures from your D90 would be fine. It's not that I don't believe you, I just want to see how accurate and reproducible your experiments really are. Anyone can say on the internet that what they're doing is absolutely perfect and repeatable so I would just like to see it in images/video.

Let me just cut to the chase since I just read hardheart's post (quoted above) and it will save me time in explaining this. Your tests are NOT reproducible for all the reasons that hardheart stated. There is a BIG difference between repeatability and reproducibility. Your experiments may very well be repeatable, but reproducibility is what matters in the "science" world. Your experiments can draw absolutely no conclusions about a steel, edge, blade, knife, etc. in general simply because your experiment is not reproducible.

Is your testing facility maintained at a constant temperature? ----- no
Is your testing facility maintained at constant pressure? ----- no
Is your testing facility free of airborne dust/dirt/particles/etc.? ----- no
Can you control the muscles in your arm and upper body so precisely as to EXACTLY replicate each movement for each experiment? ----- no
Is the composition of the rope that you cut the same throughout? ----- no
Is the composition of S30V in one knife the same as S30v in the other knife? ----- no
Can you sharpen 10,000 knives EXACTLY the same way, to EXACTLY the same angle, every single time? ----- definitely no.

Do you see my point?
Your experiments may bring you satisfaction but they do nothing to provide accurate results for wear resistance/sharpness/anything.

 

[Ankerson]

What method do you use to test Rockwell hardness? Do you have a Rockwell hardness tester? I find it hard to believe that you spent a minimum of $1000 on an accurate hardness tester...

The knives are sent off for Testing to a Custom Knife maker that has a Rockwell machine.

 

[Ankerson]

What method do you use to test Rockwell hardness? Do you have a Rockwell hardness tester? I find it hard to believe that you spent a minimum of $1000 on an accurate hardness tester...

I would also like to see a series of photos or video of your experiment set-up and process. Just a few pictures from your D90 would be fine. It's not that I don't believe you, I just want to see how accurate and reproducible your experiments really are. Anyone can say on the internet that what they're doing is absolutely perfect and repeatable so I would just like to see it in images/video.

Let me just cut to the chase since I just read hardheart's post (quoted above) and it will save me time in explaining this. Your tests are NOT reproducible for all the reasons that hardheart stated. There is a BIG difference between repeatability and reproducibility. Your experiments may very well be repeatable, but reproducibility is what matters in the "science" world. Your experiments can draw absolutely no conclusions about a steel, edge, blade, knife, etc. in general simply because your experiment is not reproducible.

Remember what I am testing for.....

I am not ranking steels in order from best to last in order 1,2,3,4,5 etc.

I am grouping them into Categories, there is a big difference.

We are looking for large differences.

There isn't any way to rank the steels from best to last in order doing it by hand, CARTA might be able to.

What my results tell is that the steels in each category will have similar edge retention related to each other, it's nothing more than that.

 

[Ultimate]

Remember what I am testing for.....

I am not ranking steels in order from best to last in order 1,2,3,4,5 etc.

I am grouping them into Categories, there is a big difference.

We are looking for large differences.

There isn't any way to rank the steels from best to last in order doing it by hand, CARTA might be able to.

I understand what you are testing but do you understand that no matter WHAT you're testing, your results are not actually substantial? You have received results from inconsistent testing methods. It's not your fault; achieving the conditions stated above by several people is VERY challenging.

I could carry out the "same" experiment as you in my own home and achieve COMPLETELY different results simply because there are SO many variables to control.

If I go into the woods in order to test how many "chops" it takes to cut down a tree, it doesn't matter if I rank the tests by number of chops or group them by range of chops. No result is accurate for obvious reasons. (Every tree is different, every chop changes the edge geometry, saturation of the tree etc.) That experiment would prove nothing.

What my results tell is that the steels in each category will have similar edge retention related to each other, it's nothing more than that.

Your results don't show that. They show that if someone were to REPRODUCE your experiment to EXACTLY the same conditions that you did, they would get the same result. The point is that NO ONE is able to do that. The results are only relevant to you. They can not be associated with all knives of the same maker, same steel, etc

 

[Ankerson]

I understand what you are testing but do you understand that no matter WHAT you're testing, your results are not actually substantial? You have received results from inconsistent testing methods. It's not your fault; achieving the conditions stated above by several people is VERY challenging.

I could carry out the "same" experiment as you in my own home and achieve COMPLETELY different results simply because there are SO many variables to control.

And it's also possible, I would say likely that if you do it the same as I do, cutting the variables down the same as I do that you could get the same results.

I would say they would be very close.

 

[Ultimate]

And it's also possible, I would say likely that if you do it the same as I do, cutting the variables down the same as I do that you could get the same results.

I would say they would be very close.

They might be close you're right. But even if I did achieve the same results as you it doesn't prove anything because my set up would have all the same variables as yours. I can not sharpen a knife exactly the same as you, I can not apply force at the same acceleration as you, I can not use rope with exactly the same make-up as you, etc.

It is like this: I light paper on fire with a magnifying glass.
Then you tried it and your paper lights on fire too.
So now we can say that if you point any magnifying glass on any piece of paper in any condition, it will light. No, we can't...