Polished edge retainsion

this really isn't about the testing methodology, since then you are comparing a postage scale to a bathroom scale, a slice versus a a rocking cut, measuring the force to cut rope versus measuring force to cut thread. There is no greater scientific rigor in one hand test over the other. Then you are left with the CATRA tests, but did they test a large enough sample on manila to be conclusive?

This is about a fundamental difference that we have all seen over the years. Vassili places his personal findings above everything else, and Broos places no value on any amateur efforts that don't conform to what published papers produce. I think the universe would implode if Vassili got himself published somewhere for peer review.
 
Yup I still think you are a backyard tester. I do understand and did take the effert to read your posts on your link. Your opinion isn't proof of anything, and your use of 1 knife isn't proof of how that steel type performs. Time and effert does not equal proof in my opinion.
 
hardheart said:
Vassili places his personal findings above everything else
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And the reply to any disagreement is always the same - "I am right and you are wrong". With little else to back up his opinion other than little insults and condescending remarks. To me it indicates a lack of intellectual curiousity, and one will never learn anything when they are convinced they are right 100% of the time.

hardheart said:
and Broos places no value on any amateur efforts that don't conform to what published papers produce.
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No. I place value on testing when the tester knows what they are doing, and are smart and wise enough to be able to defend their results logically without resorting to 4th grade arguments. And I don't think Wilson and Goddard get paid for their testing, and when someone disagrees with them they explain their views kindly, concisely, and clearly. And everyone can learn something or see something in a new way when the discussion is complete.
 
Granted compared to most, have a very very very modest collection of knives, and even fewer that get used.

I have a Gerber Air Ranger that was my work knife for 2 years. Simple liner lock, aluminum handles, no clue what the blade steel is. Will take a wicked edge, polished or not, but will not hold it all that long.

I've got 2 SOG knives in AUS8 - one is cryotreated and one isn't. The cryotreated blade seems to last a bit longer, but not a huge amount. Both hold the edge longer polished compared to 550ish grit.

I've also got 1 SOG knife in VG10 - it loves polished edges. They last an appreciable amount more than a non-polished edge in my usage. Even the non-polished edge lasts a while though.

I quit my job this week, but all of the knives were subjected to 4-8 hours of daily use from cutting zip ties, shrink wrap, paper, up to cardboard. Polished edges, depending on the knife, would make it last through the whole day without a touch up to lasting multiple days without a touch up.


When it comes down to it though, as long as there's a sharp edge on a shallow angle I don't care if it's polished or not. It'll draw and push cut fine either way in my book, and at the time I'm using it, I'm focusing on getting the job done - not if I'll have to sharpen it sooner.

I sharpen a knife daily if I use it - I forgot for the past 3 days to do that on my VG10 blade, and I'm kicking myself in the arse about it now, but it still did the job just fine and dandy every time. In my opinion, the good angle on a decent steel with a rough finish will always perform MUCH better than an ok angle on a decent steel polished like a mirror.
 
Broos said:
And the reply to any disagreement is always the same - "I am right and you are wrong". With little else to back up his opinion other than little insults and condescending remarks. To me it indicates a lack of intellectual curiousity, and one will never learn anything when they are convinced they are right 100% of the time.
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agreed. I don't know if the language barrier can be part of any excuse, but he is immovable and not at all affable when discussing these things.

Vasili, you do a lot of work, but you cant present yourself as the end all.

No. I place value on testing when the tester knows what they are doing, and are smart and wise enough to be able to defend their results logically without resorting to 4th grade arguments. And I don't think Wilson and Goddard get paid for their testing, and when someone disagrees with them they explain their views kindly, concisely, and clearly. And everyone can learn something or see something in a new way when the discussion is complete.
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They get paid for knife 'expertise', and I think they should because they are very accomplished makers. But, I don't think cutting manila rope on a scale is something beyond the rest of us. If something is wrong with Vassili's thread testing, I don't see why something couldn't be wrong with the other testing. This manual edge testing stuff isn't that complicated as it exists today.
 
hardheart said:
They get paid for knife 'expertise', and I think they should because they are very accomplished makers. But, I don't think cutting manila rope on a scale is something beyond the rest of us. If something is wrong with Vassili's thread testing, I don't see why something couldn't be wrong with the other testing. This manual edge testing stuff isn't that complicated as it exists today.
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I agree, & thanks. TNelson (one of the Professor's from BYU) also had some interesting comments about hand testing in general in an old thread.
 
I think we have to consider the objective for testing in order to evaluate test results and methods. In my case it goes back to trying to evaluate how a knife is going to perform in real life. I used to hunt a lot and this is one of the reasons I got into knife making. It is different today but 30 years ago you couldn't buy a knife that would keep an edge even field dressing a deer. My favorite was a Buck fishing knife. I liked it because it had a thin blade. The steel was 420 something and the hardness was about 53 RC. (just lately checked it on my hardness tester) My Grandad had some old power hack saw blades and he gave me a couple and I made a crude knife that did much better than the store bought one. On a phone call to Wayne Goddard (20+ years ago) I was asking how all the favorite knife steels of the day held up (440C, 154Cm 52100) in the field. He told me he tested them by cutting rope and that if I really wanted to find out to do some testing myself. Since then I have found that rope pretty much compares to deer and elk hair and also will approximate the hard skin and scales on some game fish. If a blade is optimized for this use it will do a good job pretty much on all other applications. As I got into heat treating this became more important. I found out some fundamental things. If blades are equal in dimension and sharpening then the hardest one will always stay sharp longer. A thin blade will cut with much less force than a thicker one. Depending on the steel grade and edge geometry some blades will fail by rolling and some by chipping or edge break away. An edge obtained by hand sharpening with a medium or fine SC stone will cut rope (or game) better than a finer sharped polished edge. Higher carbide percentages play a part especially on abrasive materials like rope and cardboard ( and game). In most cases as the initial very fine edge is lost by abrasion the higher carbide steels will cut longer but with more force. My testing method is pretty basic, it's the same as Wayne's since I learned from him. I have a friend who hunts all over the world and likes to compare and test knives. He also likes to cut rope. I send him knives and his results compare close enough with both mine and Wayne's. His field testing on knives I provide also compare close with his rope cutting. At this point I can make a few slices on rope and predict how a knife is going to work in the field. My methods depend on feel much more that other testers who post here but it works for what my objective is. The point is that I am looking for larger differences than others are and the methods seem to work and provide the information that I am looking for. Anyhow don't want to sound too defensive but thought some of this background would be worthwhile. The original question was "will a polished edge cut better than a courser one" Like others have said, depends on what you are cutting and what the steel grade is. Phil
 
A few other things I have learned by testing: It is very hard to make the same knife twice. So one particular test is not insurance that your will get the same results with the next one. First there is the difference in the testing method. cutting different sections of the same rope, cutting force measured on a scale, concentration of the tester ect. Then there is the differences in the knife. Slightly different heat treat (one pt Rc can make a big difference). Sharpening, different heats of the same grade steel, handle shape and finish, blade finish, ect. So the point is your try to eliminate as many variables as possible but there is always going to be error due to the human and fabrication factors. Again large differences will show up but smaller differences will get lost in the method. I know I am making the argument of those who say there is not much value in "hand testing" . I have to come back and say you can learn some fundamental things. Try to control the heat treat so that the error is on the side of too hard, grind the blade as thin as possible for the application. Test cut with each knife before it is finished and adjust the temper if there is evidence of chipping when cutting rope or prying the blade out of a slice into pine or redwood. These are for me and my method,not all makers will share the same views. Phil
 
I think a measurable difference isn't always a meaningful real world useful difference. If you can only notice a difference by measuring with highly controled tests but not in real world knife useage. What good is it? Other than argueing on the net about it. Is your test really better than mine? Yeah, for who and what?
Do you really think you can convince me the edge I use really performs less and holds it's edge less than a higher polished or coarser edge when I've tried all levels of edge finish for myself?
 
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Phil Wilson said:
...A few other things I have learned by testing: It is very hard to make the same knife twice. So one particular test is not insurance that your will get the same results with the next one...
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I think that this is because wooden base, which edge hit after cutting rope make results too variable. This is why I am cutting my rope in the air. It is very easy to make this device and try and see yourself. I gave previously quite a bit of explanation what is going on with cutting rope on wood.

This is almost same as cutting butter on ceramic plate.

Thanks, Vassili.
 
Thanks for your thoughts, Phil. I apologize for dragging you in, but I didn't think it was fair to see FFD2 get downgraded repeatedly and IMO inaccurately.
 
Vassili, Thanks for the tip. I think I already replied to this on a previous thread. I can't argue that the wood is not making a difference. I just don't agree that it is a significant difference. If you are careful at the end of the slice the force into the wood is very small and the wood I am using is very soft. If it is making a difference it is the same for each cut. I have tried newspaper under the rope and even made a jig like you suggest but I don't get the cutting feel I want. We will just have to agree to disagree on this one.

Broos, no problema. FFD2 is good stuff. My comparisons indicate that it is in the same ball park with CPM 10V. Again it seems that hardness is governing here. 10V at 64 is at a little disadvantage to FFD2 at 66 but the high carbide percentage makes up the difference. Phil
 
Phil Wilson said:
Vassili, Thanks for the tip. I think I already replied to this on a previous thread. I can't argue that the wood is not making a difference. I just don't agree that it is a significant difference. If you are careful at the end of the slice the force into the wood is very small and the wood I am using is very soft. If it is making a difference it is the same for each cut. I have tried newspaper under the rope and even made a jig like you suggest but I don't get the cutting feel I want. We will just have to agree to disagree on this one.

Broos, no problema. FFD2 is good stuff. My comparisons indicate that it is in the same ball park with CPM 10V. Again it seems that hardness is governing here. 10V at 64 is at a little disadvantage to FFD2 at 66 but the high carbide percentage makes up the difference. Phil
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My observation is based on thread statistic measurement and I see that cutting rope on wooden base give very significant impact on edge. It is like add 50 cuts to single rope cut. So this is significant difference and also I did 800 cuts for thicker rope then you have - just easy. So on my experience this is huge difference. Again I have pretty good way to see what is going on with edge.

Now cutting rope 800 times for each knife I learn that from cut to cut force to apply vary significantly, so on my observation you can not measure state of the edge by one cut on the scale - this is statistically incorrect. For thin thread I am doing 21 measurement to find median and it you case as you sad variations can be way bigger so mathematically speaking it may be 30% error in you results.

I have a question - did you test FFD2 with NIB sharpness or you sharpen it yourself? FFD2 have excellent sharpness NIB so if you start testing it with knife sharpened differentely - it willbe huge advantage, not because of steel, but because of different starting point.

My test shows FFD2 on same level as $15 Laury Progressive Tempered blades - Finnish blades out of German Carbon steel and far behind CPM S30V.

Thanks, Vassili.
 
So-Lo said:
My Spyderco 306UF will sharpen my S90 Mili. You are wrong Vassi.
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Of coure it will, but to what extent? I found it by testing it using thread cutting method. How do you see difference between sharpness after medium and after fine?

Thanks, Vassili.
 
In this thread I come to know things some of which I didn't even imagine,
vanadium carbide is harder than aluminum oxide is among them.
Very impressive.
 
Vassili, We seem to be going around in circles. I have stated before that my method is not precise. It is a good indication of differences between specific knives on one particular day with all the variables entering into the mix. Other than the increasing force applied to cut, my sharpness measurement is my educated thumb. My thumb against your thread, I can hear your laugh now. Ok, I am laughing too since someone reading this will also get a chuckle out of it. But try it first before you dismiss it. This is interesting since I spent a large part of my career debating the scientific theory against what is practical to do and make. You have confidence in your method and mine gives the information I am looking for. Most of my time is spent making knives so at this point that has to be my focus rather than developing alternate testing methods. I enjoyed this discussion but have to get back to work.
FFD2. I have two blades, one an original blank sent to me for hardness testing and cutting and another finished knife for field testing. I have been doing all my testing so far with the blank. I tried it sharpened from the factory and also I re-sharpened for additional cutting. The resharpened blade gave about the same results. Again here's some fundamentals I have learned from my practical testing.

The harder blade will stay sharp longer
A thinner blade will cut longer just because it starts out with less friction and bind in the cut.
1 point RC can make a difference on some steels.
The handle shape and leverage to the blade will make a big difference.
I like the higher carbide steels hardened to the maximum for balance between brittle and tough. I would rather have a blade micochip than roll. When it rolls you are done. Microchipping will keep on cutting, sometimes better than before. This is more important in the field than in the kitchen where a quick re-sharpen is possible
If a blade ground to .008 behind the edge and sharpened to an 20 degree angle to the stone does not roll or chip cutting rope up to about 25 lbs on the scale then the heat treat is right on.
My testing results have pretty much followed the CATRA tests results that Sal (Spyderco) gave me a couple years ago. My testing also pretty much predicts the field results my big game hunter, testing partner gets.
What is the error on my testing method? I don't think it is 30% but I can see at least 20%. Again I am looking for large differences.. PHIL
 
We are talking about different tests. One is what I am doing - collecting numbers, building tables etc... And another - which is expert opinion, when experienced specialist looks at product and report his opinion. This is like testing wines. But in your case you have your educated thumb instead of wine expert tongue or aroma expert nose etc...

Both way are valid testing which humanity developed and uses for generations. I can accept results from you educated thumb and hope I will develop same sense sometime.

Also I am focuse on more detailed data - like my tests shows dynamic of dullness, like most interestin fact that 420HC keep high sharpness much better then INFI, but after 220 cuts fall very fast, so at 800 INFI is way over. This can not be seen if you just cut rope until it stop cutting, for this INFI will show superiority easy - and Jerry proved it many times, but my finding explain why there is so many Buck enthusiasts - they prefers high sharpness and do not ming resharpen it after 200 cuts - this way 420HC will be always ahead on INFI.

Thanks, Vassili.
 
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