Edge retention testing compared - analysis

Dulling is non-linear because of the edge geometry. The very first little bit is relatively easy to remove, abrade, chip, roll, dent, etc. However, as the edge becomes thicker, it becomes less and less easy to abrade, roll, dent, chip, etc the edge. Different steels stand up to different forces in different ways. Edge retention curves are difficult to analyze because the rate of degredation due to each mechanism is different, and different for each steel. And, they are influenced by edge geometry, blade geometry, and other factors that are not intrinsic to the steel. There is not sufficient data to draw strong conclusions from this data set, save that 420 does not hold its edge as well as the other steels when tested against manilla rope.

No, we are not taking about Cliff's work. I was just noting that Cliff has shown that edge retention curves are non-linear and complex.
 
hlee said:
Dulling is non-linear because of the edge geometry. The very first little bit is relatively easy to remove, abrade, chip, roll, dent, etc. However, as the edge becomes thicker, it becomes less and less easy to abrade, roll, dent, chip, etc the edge. Different steels stand up to different forces in different ways. Edge retention curves are difficult to analyze because the rate of degredation due to each mechanism is different, and different for each steel. And, they are influenced by edge geometry, blade geometry, and other factors that are not intrinsic to the steel. There is not sufficient data to draw strong conclusions from this data set, save that 420 does not hold its edge as well as the other steels when tested against manilla rope.

No, we are not taking about Cliff's work. I was just noting that Cliff has shown that edge retention curves are non-linear and complex.
Click to expand...

yup geometry is a big factor but so is the chemical composition of the steel as is the hardness. All these factors weigh in. Media is usually not consistent enough for accurate comparative testing, however, when you have media that requires hundreds of cuts to begin getting any results the consistency improves.

You can still graph results to the 800 mark and predict what is going to happen further out to the point where the steel dulls. The most important factor in these tests is the difference from beginning to end for each steel, much more important than the starting number or finishing number. The difference is what gives the rate of wear and this is what is not understood by the tester.
 
the fact that you could deduce anything from those numbers is mind-boggling to say the least. How 'bout we just agree that INFI is cool. The rest is just gibberish.
 
I believe in INFI as much as the next Busse fan, but I am not sure that it is entirely the super steel that we wish it was. It takes a wicked beating, that is for sure. As far as edge retention, which is what I think nozh was trying to point out, there are better slicer steels out there. I really doubt there is anything tougher than INFI though, even SR-77.
 
GOD!!! what part of the results do you guys not understand. I just graphed the results from the testers test and the slope of the INFI curve is much shallower than D2 which means that these two curves will meet at what looks like 1100 to 1200 cuts, then if the curves remain true to form, D2 will continue to drop at a faster rate. I did not make my graph big enough to see at how many cuts they will reach 270 grams, but that will be my next prediction.

YES, INFI DOES DULL AT A LESSER RATE THAN FFD2, PERIOD. GRAPH IT YOURSELF AND SEE.

nozh2002 said:
Cut INFI 420 ATS FF LAU
000 040 030 040 020 020
001 060 050 060 030 020
002 070 050 070 040 030
003 070 060 070 040 030
004 080 050 070 040 040
005 080 060 070 040 040
006 080 060 070 040 050
007 --- 070 080 040 050
008 080 080 080 040 050
009 --- 070 080 050 050
010 070 070 080 040 050
012 080 070 080 050 050
015 080 080 090 050 050
020 080 070 090 050 050
025 080 080 090 050 050
030 090 080 090 050 060
035 090 080 090 050 060
040 090 090 090 060 060
045 090 070 090 060 060
050 080 080 090 060 060
060 090 070 090 060 060
070 --- 080 090 060 060
080 100 080 090 070 070
090 110 080 --- 070 070
100 110 080 090 070 070
110 110 080 090 070 070
120 110 090 090 080 070
130 110 090 090 070 070
140 100 080 090 080 070
150 110 090 100 090 070
160 110 100 100 100 080
170 120 110 100 090 080
180 120 110 100 080 080
190 120 110 100 080 080
200 130 100 100 090 080
210 120 110 100 090 080
220 130 110 110 080 080
230 110 --- 110 090 080
240 110 130 110 090 080
250 110 130 110 100 080
260 110 130 110 100 090
270 110 140 110 100 090
280 110 130 110 100 090
300 110 140 110 090 090
320 110 140 120 100 090
340 120 150 120 100 100
360 120 140 120 110 100
380 120 140 120 110 100
400 120 140 130 110 100
420 110 140 130 110 100
440 110 140 130 110 100
460 110 150 130 110 100
480 110 160 130 110 100
500 110 170 130 110 100
520 120 170 130 110 110
540 120 170 130 110 110
560 120 180 140 110 110
580 120 190 140 110 110
600 120 200 140 110 110
650 130 230 140 110
700 130 260 140 120
750 130 --- 150 120
800 130 --- 150 120

Click to expand...
 
I just graphed them out to 2000 and neither gets close to 200. For example at a predicted 1950 cuts, INFI is at 170 grams while FFd2 is at 190, not a great difference if they continue to deteriorate at such a pace. The difference will continue to grow but since both curves are flattening out, the difference will not rise at such a drastic rate.

Of course this is only a prediction based on current results, but the degradation curve of INFI is definitely better than FFD2, graph it yourself and see. If you take a starting point at 25 cuts and then go every 100 cuts it makes the curves easier to read since there is so much error in these tests.
 
hlee said:
Dulling is non-linear because of the edge geometry. The very first little bit is relatively easy to remove, abrade, chip, roll, dent, etc. However, as the edge becomes thicker, it becomes less and less easy to abrade, roll, dent, chip, etc the edge. Different steels stand up to different forces in different ways. Edge retention curves are difficult to analyze because the rate of degredation due to each mechanism is different, and different for each steel. And, they are influenced by edge geometry, blade geometry, and other factors that are not intrinsic to the steel. There is not sufficient data to draw strong conclusions from this data set, save that 420 does not hold its edge as well as the other steels when tested against manilla rope.

No, we are not taking about Cliff's work. I was just noting that Cliff has shown that edge retention curves are non-linear and complex.
Click to expand...

Agreed. "Sharpness" is, so far as I can tell, a poorly defined quantity. The fact that previous attempts to create edge retention curves displayed non-linear behavior is absolutely no surprise.

Sometimes, the simplest things turn out to be, in reality, quite complex. Absolute measurements are extremely challenging to make. Even relative measurements (today's topic) are rarely simple, especially when you depart from fundamental quantities like mass or charge and enter the rarefied realm of everyday language.

I think I recall trying to post in a previous Thread on this topic, but my attempts to help were received poorly. I moved on. :)

As far as I can tell, Cobalt's methodology for reducing this data is, absent a sophisticated analysis of the experiment itself, perfectly valid.

Oh -- and Hlee is clearly at least a graduate student in a materials science.
 
Because this thread is useless without pictures :D...

All data
all_steels.png


INFI vs FFD2
infi_ffds.png


Data taken from http://playground.sun.com/~vasya/Manila-Rope-Testing.html
 
very cool point to point graph but not very helpful. See how much error there is from cut to cut, thus, to remove the error and get the mean for the system take an average and extrapolate an actual smooth curve out of it like I did by hand and how I use to do in my engineering days? That will give you the true direction of the curve. The graph shown is an exact representation of the written data, it helps nothing since there is no average or mean curve represented.

If you have a hard time making a curve out of the data that averages the numbers, then what you can do instead is take sections of data and average them and take that average as one data point. For example, you take the first 10 cuts and average the number, and you use that number as your starting value, which is going to be more accurate than the value originally given since there is so much variation here.

Then you take groups of numbers and average them, so say take the next 50 cuts and make one average and use that as a data point. This gets rid of the fluctuation since you are using the law of averages to smooth out your graphical representation.
 
OP, hlee is currently a postdoctoral associate in biochemistry, specifically transient state enzymology.
 
hlee said:
OP, hlee is currently a postdoctoral associate in biochemistry, specifically transient state enzymology.
Click to expand...

very cool, I hate chemistry and my entire family is made up of degreed chemists and biochemists except my granfather who was a mechanical engineer like me, so kudos to you for sticking with it.
 
Sharpness may be simpler than transient state enzymology. We'll need to do some single-molecule experiments to find out. ;)
 
You need to take a Bonferroni interval. (Not entirely relevant to this discussion but I've always wanted to say that!)
 
Okay. . . Here's what I've got so far. . . We, at Busse Combat, cut over 2,700 pieces of 1" hemp rope at the 1999 BLADE Show with a 2" wide section of the 1/4” thick blade and over 3,100 pieces at a show in Nashville and then bent that same knife over 70 degrees without breaking . . . We ran out of rope both times. . . The knives still easily shaved paper after all of these cuts. . . We have invited the entire industry to duplicate our tests. . . None have, because none can. . . I repeat . . . “None have, because none can!” . . . Period! . . . It's really rather simple. . . Don't believe me? Call any other manufacturer out there and ask them to duplicate our tests in a "LIVE" demo at this year's BLADE Show with a knife of similar dimensions. . . Then come on back and hang out with the guys who have actually done it and not theorized about it. . . Theories are cool. . . but then so is the Tooth Fairy. . . We are more interested in proven performance than theories. . .

Here are more random thoughts:

[ 1 ] There are far too many factors in sharpening a knife to ever get equal sharpness amongst different steels. . . ie; feathers break off easily on D-2 and 420HC giving the impression that they take a better edge. . . Feathers are very difficult to break off on INFI because they carry the same toughness as the rest of the blade. Thus an INFI blade may not feel as sharp initially and will actually get sharper as you continue to cut because you are wearing the feather down . . . blah. . blah. . .blah. . .

[ 2 ] I get tired of feeling like we are supposed to apologize for INFI kickin' the crap out of every other steel out there. . . . . Here I am kids, more than 8 years after our first "LIVE" demonstration, waiting for ANY other manufacturer to simply shut up, step up, and duplicate our tests. . . If you can beat our numbers I'll be glad to bring more rope and raise the bar so high that your nose will bleed just looking up at it. . .

[ 3 ] Listening to someone theorize about a knife steel's performance based upon the analysis of the steel, is as ridiculous as a food critic writing a review about a cake that he has never tasted, based on the ingredients!!! I don't care what you put in that cake, if you don't know how to bake it, it's gonna be pretty darned bad! :D

[ 4 ] Is this a blog?. . If so, am I blogging?. . . What does that mean????

[ 5 ] Merry Ho Ho. . . :cool:

[ 6 ] God Bless Our Troops who put it on the line every day. . . :thumbup:

[ 7 ] Just because one or two guys don't like our knives or don't see the performance advantage of our steel doen't really change the facts which have been proven in so many "LIVE" tests. :)

[ 8 ] I need more scotch. . :thumbup:

[ 9 ] There are lots of great knives out there. . . But if I thought for one second that there was something better than what we are making . . . I would change what we are doing in a heart beat!!!!

Let's Drink!!!

Jerry :D
 
Well said Boss HOG!

Oooops! Did I just drink more kool-aid? ;)

The "Live Test" thing is the clincher for me. I can be a real Doubting Thomas at times. Not to be difficult but simply because I have this drive to know for sure.

INFI has not let me down yet. :D
 
Tyrkon Lawson said:
Oooops! Did I just drink more kool-aid? ;)

INFI has not let me down yet. :D
Click to expand...

If you drank more Kool-Aid, then so will I, Tyrkon! :D I'm not a materials specialist, I'm a nurse who dabbles in paleopathology. I use my Beloved Hell Razor and it has never failed to do what I have asked of it. :thumbup:

I was interested in the question that has not yet been answered: what more do you require of a knife that INFI doesn't do?:confused:

Anyway, no offense intended to anyone here. I need more scotch, too!

A girl needs a knife...
 
Jerry Busse said:

[ 4 ] Is this a blog?. . If so, am I blogging?. . . What does that mean????


Jerry :D
Click to expand...

isnt a blog those things they used to stick in milk bottles, then a few years ago little kids started trading them?

blogging is the game they played with the blogs.
 
You must log in or register to reply here.
Back
Top