Kohai999
Second Degree Cutter
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No, and it IS a nice review.
I am more interested in Dr. Bias's personal feelings re
bjectivity.Best Regards,
STeven Garsson
-
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Rope slicing test CPM D2 vs. D2
- Thread starter gunmike1
- Start date
No, and it IS a nice review.
I am more interested in Dr. Bias's personal feelings re
bjectivity.Best Regards,
STeven Garsson
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Mike,
I see you used identical sharpening procedures (equal angles and equal grit finish) on each test blade for this test.
Cliff objected repeatedly (and you also posted similarly, though nicely) in the FFD2 thread to Diamondblade using equal geometry and equal grit finish for their tests. You guys stated that the edge finish and geometry should be "optomized" to the steel for the test baseline. I can indicate the posts if you do not recall these posts.
CPM D2 has finer grain, which makes this test ideal for your "optimization" of edge finish and geometry.
Have you guys seen the light, and now agree that equal finishes and geometry is the correct test baseline? To be honest, I'm still shaking my head over the contention that edge retention testing to compare different steels should be done at varying geometries and finishes - to my way of thinking this is a patently unscientific basis for an equal comparison.
I still like your test - I'm just wondering why the cutleryscience tests do not address the same criticisms cliff raises against many other tests posted here.
I see you used identical sharpening procedures (equal angles and equal grit finish) on each test blade for this test.
Cliff objected repeatedly (and you also posted similarly, though nicely) in the FFD2 thread to Diamondblade using equal geometry and equal grit finish for their tests. You guys stated that the edge finish and geometry should be "optomized" to the steel for the test baseline. I can indicate the posts if you do not recall these posts.
CPM D2 has finer grain, which makes this test ideal for your "optimization" of edge finish and geometry.
Have you guys seen the light, and now agree that equal finishes and geometry is the correct test baseline? To be honest, I'm still shaking my head over the contention that edge retention testing to compare different steels should be done at varying geometries and finishes - to my way of thinking this is a patently unscientific basis for an equal comparison.
I still like your test - I'm just wondering why the cutleryscience tests do not address the same criticisms cliff raises against many other tests posted here.
Sal Glesser
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Hi Broos,
We prefer to use the same angle and geometry, but vary each for both materials in different tests. This enables us to see an optimal geometry as well as compare at each geometry.
IMO, It CATRA edge retention testing, the more highly polished the edge, the longer it will resist abrasion, all other things being equal.
sal
We prefer to use the same angle and geometry, but vary each for both materials in different tests. This enables us to see an optimal geometry as well as compare at each geometry.
IMO, It CATRA edge retention testing, the more highly polished the edge, the longer it will resist abrasion, all other things being equal.
sal
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great write-up!!
I enjoyed reading it
I enjoyed reading it
Cliff Stamp
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One thing which has to be made very clear is that the advantage of the high edge stability steels will only be an influence at low angles. If you compare 1095 vs 154CM at 20 degrees it is very different than both 10 degrees. Johnston noted this on rec.knives when he compared his 1095 blades with Bos's ATS34 blades for tradesmen. With the common promotion of very high edge angles it is no wonder that high carbide steels are also so popular. But CATRA testing is biased towards high carbide steels in general due to the very low lateral loads as the blade is held very rigid during the cutting, something no human can can duplicate. It is basically a wear base test so care has to be taken with extending it to edge holding in general as it isn't well correlated to use by people as clearly noted by Buck when they tested the Ionfusion blades.
Assuming the cut is dominated by a push then a higher polish would resist damage better which is all abrasion is on a micro-scale. There are a few guys doing work on chisels done planing woods with various steels which is quite interesting. They are doing comparisons of up to a dozen blades at once with multiple trials so the data is slow in coming but there is a wealth of it.
Note that there are a lot of different media which can be used in CATRA testing, it is not just abrasive paper which sometimes seems to be the image that people have. CATRA had done studies on coarse edges cutting ropes and confirmed what Swaim had shown on reck.knives about ten years ago, that the edge retention while slicing is much greater with a coarse edge (Swaim started with filed edges). This of course is just basically saw vs axe mechanics.
-Cliff
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Time is the reason I didn't get a chance to vary the geometry or grits like I wanted. Testing the differences in optimal geometry and the ability of each steel to take and hold a high polish was something that really interested me, since they are the same composition (with the same carbide fraction), except one uses the CPM process for finer grains. From my experience I like to go with the thinnest edge possible while avoiding edge damage to maximize cutting ability, and it takes a lot of cutting and experimenting to find that. Sal's method of testing both knives at the same geometry side by side and then continuing to test them at varying geometries sounds like a good way of testing to find the optimal geometry for each steel (this will also of course depend on what you are cutting and how you are cutting). There was a LOT more I wanted to test, but considering how long it took me to do the testing I did (it was a lot of work for one guy in his spare time) and that I have a family and 50+ hour a week job it wasn't in the cards. I decided to use the profile I have on my Manix of 10/15 per side, to save time. As Cliff said earlier, hopefully the whole group varies the geometry and finishes so that we can see the relative performance of each knife at different angles and finishes, as well as any differences with different sharpening media in all sorts of cutting situations.
Mike
Cliff Stamp
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It does take quite some time to perform the above class of work, a valid point is raised though, if the CPM D2 blade has a higher edge stability, then it should be able to hold a higher polish at a lower angle. As you noted, hopefully different people can try different edge configurations and we will see what happens.
It would be interesting to see push cutting trials at 30,20,10 per side and see if there is a difference in the edge retention ratios. One would suspect that the CPM blade would pull ahead at the lower angles, if at all. Of course to do that requires at a bare minimum of 18 edge retention runs and personally I would feel more comfortable with 30 (five per knife).
That is why I tend not to place demands on people doing things freely as a hobby. A request for about 60 hours of work is not such a trivial statement. As noted, let us let people do what they want and see what comes out of it. As the work gets done we can make decisions on what else would like to be seen and hopefully someone will decide to do a part of it.
As we have here in any case is an excellent start for slicing aggression at a decent medium/heavy profile.
-Cliff
Kohai999
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1. And that is what it is...a start.
Cliff is avoiding the question concerning his objectivity. If he is accepting product at no cost...does it not stand to reason that his objectivity is compromised?
Now....if it was a maker or manufacturer doing this....everyone reading the thread would be crying "FOUL"...joining the Cliff chorus that evasion/avoidance is bad, and they must have something to hide.
What does Cliff have to hide?
Best Regards,
STeven Garsson
Gunmike1,
I'm almost ready to start, will do so this weekend. When you tested the edge by putting the knife up to the string, I'm assuming that you then measured the amount of slice for the cut. How did you keep the string from moving with the knife? Did you continue to hold it with your off hand? I'm going to be experimenting a little, and have an idea that might be different.
I'm going to go both rough and high polish. I can put whatever bevels people want into it with my edgepro, but am afraid to alter the knives too much for the next user. Cliff, is it ok if I thin them out a little, or should I leave them the same?
I'm proposing 3 runs each at 10, 20, and 30, both rough and polished. Then I'll throw in a couple of my own knives, just for grins. I seem to recall owing someone (Hob? Dog of War?) an S30V test. May the best knife win!!
I'm almost ready to start, will do so this weekend. When you tested the edge by putting the knife up to the string, I'm assuming that you then measured the amount of slice for the cut. How did you keep the string from moving with the knife? Did you continue to hold it with your off hand? I'm going to be experimenting a little, and have an idea that might be different.
I'm going to go both rough and high polish. I can put whatever bevels people want into it with my edgepro, but am afraid to alter the knives too much for the next user. Cliff, is it ok if I thin them out a little, or should I leave them the same?
I'm proposing 3 runs each at 10, 20, and 30, both rough and polished. Then I'll throw in a couple of my own knives, just for grins. I seem to recall owing someone (Hob? Dog of War?) an S30V test. May the best knife win!!
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But sodak, the best production knives don't contain S30V. Kershaw's External Toggle and JYDII use 13C26, Ranger Knives standard RD series use 5160, Spyderco's Caly3 has options of VG-10 and ZDP-189, Swamp Rat's Howling Rat Little Mischief has 52100, and Takeda Hamono's 240AS gyuto has Aogami Super.
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Actually, I was being silly. S30V is in a lot of great knives, just not my favorites.
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Kohai999
Second Degree Cutter
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Cliff purports to not have strong feelings one way or the other on the Forums.....he may have me on ignore.
The methods that have been used here are the VERY methods that Cliff uses on makers and manufacturers...thread highjacking and...the planting of a seed of doubt.
It is not the information that he propagates or the questions that he asks...it is the way that he asks it.....devoid of consideration, manners or decency.
Best Regards,
STeven Garsson
Cliff Stamp
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Yes, do what you want edge geoemtry wise.
Nice amount of work, especially with that type of testing.
No, just on my ignore list. If you want to ask sensible questions no problem, otherwise not.
In regard to the section you quoted, accepting donated products is a clear possibility of bias as your sample (in this case the Military) could be hand picked or otherwise adjusted to give a skewed example, it could be individually hardened, hand finished, etc. This is why it should always be noted that it was donated so people can keep this in mind. If at all possible it should be referenced to random picked items.
In regards to the samples for the test group, these in general are going to be made to order. A maker volunteered for example to send me identical test blades in low and high carbide steels for an edge stability check. The people using them will not know which blade is which steel or even who made them so they can not artifically promote anything.
There is the possibility that the maker is trying to make some point with the steels and mishardens one of them to intentionally lower the performance. For example someone does not like 154CM and thus blows the grain intentionally. Of course I will keep such things in mind and all the information will be cross checked and correlated with other data. At the end all will be released which tends to make such concerns not very large in my mind.
This is a work in progress, both in terms of the work done by the testors and as well how the blades are obtained and the information used. It is a long term project and we will see how it goes. If you want to be part of it, excellent. If you want to sit on the sidelines and complain then you are free to do that as well.
-Cliff
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This is a reasonable question. I'd like to know the answer. If you're going to use the scientific method, you must address the question of objectivity...remove the very human elements of motivation and emotion.
I know it's been a problem for me in the past!
Sal Glesser
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I enjoy all of the testing and opinions. I also learn a great deal. I do not always agree with everything everyone says, but it all goes in as data.
What makes this intesting is we are seeking to find methods of comparisons. Comparisons are best made with measurements. Measurments too, have their limitations, which is what makes this an interesting and conroversial subject. I would rather not discourage anyone from doing any kind of testing they are interested to try.
We own many thousands of dollars in testing equpiment, but all of it is in "tuth seeking", at least from our point of view. I derive much pleasure in the many ways knife afi's come up with to test for comparisons.
We learn incrementally. absolutes? I doubt it. Some thoughts to share;
"I know it's sharp, I heard it".
"Statistics don't lie, but statisticians lie like hell"
"You can find testimonial for anything up to and including the guillotine for dandruff control"
"What is the accurate mesurement for the heigth of an orgasm?"
"How do we measure the "chi" used to break 10 bricks?"
The "truth seekers" here are doing a great job, please continue.
sal
----------------------------------------------------
"We are all teachers and we are all students"
What makes this intesting is we are seeking to find methods of comparisons. Comparisons are best made with measurements. Measurments too, have their limitations, which is what makes this an interesting and conroversial subject. I would rather not discourage anyone from doing any kind of testing they are interested to try.
We own many thousands of dollars in testing equpiment, but all of it is in "tuth seeking", at least from our point of view. I derive much pleasure in the many ways knife afi's come up with to test for comparisons.
We learn incrementally. absolutes? I doubt it. Some thoughts to share;
"I know it's sharp, I heard it".
"Statistics don't lie, but statisticians lie like hell"
"You can find testimonial for anything up to and including the guillotine for dandruff control"
"What is the accurate mesurement for the heigth of an orgasm?"
"How do we measure the "chi" used to break 10 bricks?"
The "truth seekers" here are doing a great job, please continue.
sal
----------------------------------------------------
"We are all teachers and we are all students"
Cliff Stamp
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Removing them is large impossible, the very act of questioning is itself a human trait. I have outlined ni the above the general approach being taken, if you have any comments on it they are welcomed.
Yes, this is the goal here, to come up with some methods that everyone can use to judge performance and obtain useful information in a limited period of time. Of course the absolute optimla method is to just ealuate the knives as they are meant to be used on the job/hobby. The reason you use tests of some kind is to just short the evaluation period, you trade off information for speed, this is the basics of experimentation in general.
-Cliff
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Very well put, Sal. I am just a knife hobbyist who was looking to test out the relative performance of 2 knives, or as you put it "truth seeking". This is my first measured test, and although I did pirate a lot of the methods and materials from what others have already done, it was still a lot of work and a learning experience for me. Getting critical feedback and ideas from others on testing can do nothing but help me in any future testing that I try. This test is certainly very low tech and not lab quality (though I don't think testing needs to be lab quality to gather pertinant information), but it was the best I could come up with on a limited budget of money and time. There was much more I wanted to test, in terms of different profiles and especially higher polish, but my time just ran out, as family comes way before hobbies.
Also, those are some great quotes to add some levity and perspective here!
I really applaud Sodak for his test, that is going to be a lot of work! That many profiles and finishes are going to take some time! As far as cutting the twine, yes I continued to hold it with my off hand. After some practice and trial runs I got used to the feeling of holding the twine level and got pretty consistent results. I would love to hear of your idea, anything to add consistency or get more accurate results is good in my book. One question about the Edge Pro: with the full flat grind on the Military and the convex grind on the Mel Sorg how do you make sure you sharpen them to the same angle? I know when I used the Edge Pro on the Military I had to go to a more obtuse setting to get close to an actual 15 degree angle on the cutting edge due to the angle of the flat grind. This was confirmed when I freehand sharpened (by propping up the end of the stone to 15 degrees) the knife after sharpening on the Edge Pro and using it that I was getting all the way to the edge even though the Edge Pro had to be raised to a setting a few degrees higher (I think it was 3-4 degree above 15, but truthfully don't remember) to achieve the same angle. I guess you can measure the angle of the platform of the Edge Pro, then the angle of the blade as it rests on the platform to get the difference. I'm a complete newbie with the Edge Pro (thanks for letting me try it, Thom), so bear with me on this question. Again, I really applaud your testing, that should be fun, but a lot of work. I look forward to the results.
Mike
Kohai999
Second Degree Cutter
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Great job at gently directing the question away from Cliff, Sal.....you should be proud.
I'm not playing.....if Cliff doesn't want to answer the question....since you just deflected...maybe you want to answer it in his stead?
Do you feel that an "objective" testor(Cliff) being provided knives-gratis, compromises integrity...something that you have a great deal of, and know about?
Best Regards,
STeven Garsson