Steel Edge Retention testing

[NuclearBossHog]

Well, it should be easy to test... Run side by side thin vs thick edge with same steel. May be I'll do this sometime.

Thanks, Vassili.

this would be good test, to see if the edge type does make a difference as well as the thickness of the blade near the edge. I think the results will differ because as you were down the edge the thicker knife has more surface area making it harder to cut with, just what makes sense to me, anyway.

 

[Larrin]

With this type of testing differences in thickness may be less obvious, since the sharpness testing has nothing to do with the edge thickness, but the thinner knives will cut much better, sharpness being equal.

 

[NuclearBossHog]

With this type of testing differences in thickness may be less obvious, since the sharpness testing has nothing to do with the edge thickness, but the thinner knives will cut much better, sharpness being equal.

that being said then a thinner knife should last longer for the same steel used.

 

[nozh2002]

I am wondering did you read my post? I did explained it several times and directly ask you to expose your opinion.

Is it something not clear in my explanation? To me it looks strange - I spend quite a time and effort to explain what and why but feel like I am talking to brick wall. If something is not clear please let me know otherwise it looks like I do not worse you attention or something.

Thanks, Vassili

 

[Larrin]

I am wondering did you read my post? I did explained it several times and directly ask you to expose your opinion.

Is it something not clear in my explanation? To me it looks strange - I spend quite a time and effort to explain what and why but feel like I am talking to brick wall. If something is not clear please let me know otherwise it looks like I do not worse you attention or something.

Thanks, Vassili

My opinion is that this type of testing won't tell you much if you are trying to compare a thick edge with a thin edge.

 

[NuclearBossHog]

I am wondering did you read my post? I did explained it several times and directly ask you to expose your opinion.

Is it something not clear in my explanation? To me it looks strange - I spend quite a time and effort to explain what and why but feel like I am talking to brick wall. If something is not clear please let me know otherwise it looks like I do not worse you attention or something.

Thanks, Vassili

excuse me, why do you have to get insulting.

I do not agree with you that edge thickness is irrelevant and it seems that neither does larrin. I think if you ask most knifemakers, you will find that edge thickness and blade thickness is important in testing.

but the only real way to find out is to compare two knives of the same steel. How about the spyderco in D2 and a much thicker sabre ground knife of D2, that should be easy enough to find. Or maybe a Spyderco of VG10 against a Falkiven A1 of VG10 non laminated.

This is an important aspect I think.

 

[Any Cal.]

I believe that nozh is trying to say that while edge thickness and blade thickness are important, he has worked hard at designing a test that makes them immaterial. Imagine trying to cut a piece of cardboard 12" long. Obviously, you would feel the difference. Vassili's test however, is conducted on a portion of the blade and with a material that makes the difference between thin and thick edges basically immeasurable. While there may be a measurable difference between a 5* and a 45*, the difference of a few * would not be measurable in this medium or style of testing. That is why he keeps saying the edge thickness is unimportant. The media never has a chance to reach the upper limits of any thickness.

 

[Any Cal.]

And by this I am referring to the string that he is using to collect his data.

 

[NuclearBossHog]

I believe that nozh is trying to say that while edge thickness and blade thickness are important, he has worked hard at designing a test that makes them immaterial. Imagine trying to cut a piece of cardboard 12" long. Obviously, you would feel the difference. Vassili's test however, is conducted on a portion of the blade and with a material that makes the difference between thin and thick edges basically immeasurable. While there may be a measurable difference between a 5* and a 45*, the difference of a few * would not be measurable in this medium or style of testing. That is why he keeps saying the edge thickness is unimportant. The media never has a chance to reach the upper limits of any thickness.

this may be true and may be not. The way to do this is as larrin suggested and as even Vassili indicated as being testing the same steel in many edge types. This would prove his point.

 

[nozh2002]

excuse me, why do you have to get insulting.

I do not agree with you that edge thickness is irrelevant and it seems that neither does larrin. I think if you ask most knifemakers, you will find that edge thickness and blade thickness is important in testing.

but the only real way to find out is to compare two knives of the same steel. How about the spyderco in D2 and a much thicker sabre ground knife of D2, that should be easy enough to find. Or maybe a Spyderco of VG10 against a Falkiven A1 of VG10 non laminated.

This is an important aspect I think.

OK, eventually, I'll do this test. But thickness of the blade is not important for edge retention testing. Period.

Thanks, Vassili.

 

[nozh2002]

Santa bring me gorgeous Busse Active Duty Black-Black G10. I sharpened it to 20g, so I may retest INFI from same sharpness level as latest tests.

Thanks, Vassili.

 

[Last Visible Canary]

OK, eventually, I'll do this test. But thickness of the blade is not important for edge retention testing. Period.

Thanks, Vassili.

To translate (I think):

The thickness of the spine will directly affect your ability to push cut through the rope. The thicker the knife, the more pressure you will have to apply in order to push cut through the rope. Wether you apply more pressure on the knife in order to cut through the rope or not, you are still cutting the same amount of rope. The thickness of the spine will not directly effect how the string is cut, because the string does not have any binding ability. The sides of the knife never touch the string, it snaps after passing along .5mm of the cutting edge. so the thickness of the spine can have no effect on how the string is cut.


I believe that your edge angle will have more of an effect on how the particular steel dulls and blunts (thus how it cuts the string) then spine thickness will.



If I'm getting that wrong, and vasilli is trying to say that edge angle plays no part in how the edge blunts during the cutting of the rope, then I disagree with him whole heartedly.




additional thoughts:
as long as the knife does not hit wood after it cuts the rope, you are cutting the same amount of fibrous material wether your appling more pressure to the knife or not. HOWEVER, if the edge hits the wood underneath the rope - then you have a serious variable that will effect how the knife dulls. If you apply more pressure to the thicker knife to get it through the rope and thus hit it against the wood with more pressure then the thinner knife - you are adding extra stress to the thicker knifes cutting edge then you are with the thinner knife.

 

[nozh2002]

If I'm getting that wrong, and vasilli is trying to say that edge angle plays no part in how the edge blunts during the cutting of the rope, then I disagree with him whole heartedly.

Let me quote myself

blade geometry does not matter for this tests - only angle is what may be important and it is same for all blade.

It is amaising - how many words we have here simple because what I wrote were ignored!

Once again - rope is made from many threads which does not bind to each other and when single thread of this rope cut it does not resist to blade any more, it just fall aside. So is edge or spine thick or not does not matter when you cut rope, especially near end.

Once more - thread with 0.1 mm in diameter will interact only with 0.1 mm of the very edge until it will be cut, it will not resist after it is cut. If you have 2 threads - they will interact with 0.1mm of very edge too - once one cut it will not resist any more. If you have 3 threads they will affect only 0.1 mm of the very edge. If you have 200 threads then they will affect only 0.1mm of the very edge for same reason - one one cut - it will not resist any more. It you have rope made of 200 threads - same deal.

The only number of this threads will do impact, because edge wear out more after 200 threads then after one, but it is same as cutting single thread 200 times. So edge thickness (but not angle) does not matter (until it worn out by many threads cut, which is not likely). Blade thickness does not matter. Blade cross-section does not matter and blade geometry, length, blade finish and handle material does not matter also.

Should I explain more? I it is just more confusing?

Thanks, Vassili.

 

[nozh2002]

HOWEVER, if the edge hits the wood underneath the rope - then you have a serious variable that will effect how the knife dulls.

If you check this link from this post (second post in this thread) you may see that I have special device which does allow me to cut rope without hittin anything else.

Being able to test sharpness of the edge now I can put some load on it and see how this affects sharpness.

I tried balsa wood, felt and now 1/2" manila rope - fibered structure ot rope make cutting almost independent from blade cross section geometry.

So I cut manila rope:

http://www.youtube.com/watch?v=3LgFny0ZQEU

and then check sharpness to see how this or that steel hold the edge during manila rope cutting.

This is another video from another post (#156)

http://www.youtube.com/watch?v=O8_C7jV_gI4

Finally i finished Friction Forged D2 testing. It shows best result in my tests all over scale, it is better on high sharpness and small load as well as at 800 cuts.

I like to test ZDP189 and see how it will be against Friction Forged steel as well as CPM 10V. But for now Friction Forged D2 by DiamondBlade is the best in my tests.

Here I tape part of the testing from 765 to 770 cuts, it now, with vacuum machine, goes much faster.

http://www.youtube.com/watch?v=O8_C7jV_gI4

Thanks, Vassili.

So it is all here already. It will really save some effore and resolve questions if you read at least first page of this thread where everything is explained.

Thanks, Vassili.

 

[Last Visible Canary]

fair enough, I appologize. won't happen again.

 

[NuclearBossHog]

I did not mean the spine thickness, I did mean the edge type and thickness.

To say that one thread will not have an affect on the edge profile of a knife, I would agree, when you bundle the thread up into large number then you have changed the entire dynamics of the cut and I do believe it has an impact on the edge profile and thick.

It is like saying that cutting thin piece of wood sheet 1/16 inch thick is no different than cutting through a plywood sheet made of up 6 of those thin sheets. That plywood sheet has cross grains that make it stronger. Similarly, a rope made of many threads is stronger and tougher than a single piece, and this is why ropes are made this way.

I do believe that thickness at the edge as well as edge profile will have an effect on your cutting performance in the long run. When you start wearing into the edge, the thicker profile will become much harder to cut since there is more surface area at the edge.

This is why knifemakers will call knives sharpened pry bars in cases. I think they mean that the knife can't cut due to it's edge profile being too thick.

I think your idea of testing different thick edges in the same steel is good. This might be an informative test for many reasons.

no matter what your tests as well as others are excellent

 

[db]

Rope is not wood. The fibers/threads in the rope fall away as they are cut. It is a really simple concept and easy to understand. You can notice it easily just cut a piece of rope near the end of the rope instead of arguing on your computer.

 

[NuclearBossHog]

Rope is not wood. The fibers/threads in the rope fall away as they are cut. It is a really simple concept and easy to understand. You can notice it easily just cut a piece of rope near the end of the rope instead of arguing on your computer.

I have cut plenty of rope but never for testing purposes only in real life scenarios maybe why I have so few postings. I guess if some knifemakers who actually do these tests chime in, it might be more believable. David Boye has done tests I think.

 

[nozh2002]

I have cut plenty of rope but never for testing purposes only in real life scenarios maybe why I have so few postings. I guess if some knifemakers who actually do these tests chime in, it might be more believable. David Boye has done tests I think.

Well, I can not help. I do not think I will became knifemaker any time soon so you can not trust me then. I think there is no value for you in this test if you criteria is so narrow. I am not knifemaker and I do not have identical knives with all different steels, Sorry.

I will continue my non believable tests for others non knifemakers folks or for myself only, if you don't mind.

Thanks, Vassili.

 

[NuclearBossHog]

Well, I can not help. I do not think I will became knifemaker any time soon so you can not trust me then. I think there is no value for you in this test if you criteria is so narrow. I am not knifemaker and I do not have identical knives with all different steels, Sorry.

I will continue my non believable tests for others non knifemakers folks or for myself only, if you don't mind.

Thanks, Vassili.

I did not mean to offend, I just mean that when you make such statements of fact it is good to have actual testing to back it up. As for knifemakers, I meant that since you have not actually done that test, maybe they can support your statement.

I am sorry that I cannot see your argument, but please don't think that your work is not appreciated, because it is. I really enjoyed seeing how a steel reacts to continued cutting, they are very informative,
thanks