No edge on AUS6 blade

[crispy]

WOW!!! Guys thanks for all the advice.

Cliff, I did what you mentioned in your first post. I cut into the side of my stone a couple times, then resharpened. I used a slighty more obtuse angle. It seems a lot better now, but still not as sharp as I might like it.

Maybe I should get a sharpmaker and give that a try :thumbup:

 

[Cliff Stamp]

Those steels can be difficult to get really sharp. Yesterday I reset the edge on my small Sebenza to 15 degrees, I usually run a 20 degree microbevel for no real reason other than that is where the sticks usually are for edge retention comparisons. It took about ten passes per side on the medium rods to reset the micro-bevel (the primary is five degrees) from 20 to 15.

I took a couple of lightly elevated passes at 20 then some work on chromium/aluminum oxide cleaning before and after on plain leather. The edge was above shaving on both sides. In comparison it would take *much* longer to do the same thin g on the softer stainless and based on past experience I would likely have to reset the edge a few times before I would be satisfied.

I would suggest working with the edge with the new finish for awhile and aiming to improve on your sharpness with each session. It may more more than a little frustrating to try to get optimal performance right away on the problematic steels.

-Cliff

 

[STR]

Some steels are not worth all that effort in my opinion. I have AUS6 and 8 blades that get sharp with no burr but they are dull in about ten cuts on rope or fiberglass tape tests I've done with them comparing them to D2 or some other better edge keeping steel. You can still make them cut but the effort is much higher than a premium steel. To me it isn't worth all that fuss when the edge doesn't last that long to begin with, even when its perfect on these lower grade steels.

Steve

 

[Cliff Stamp]

If they are dull in 10 cuts on rope then the steel is either defective, there is a burr or the ege angle/grit is really unsuitable. Mild steel can make 128 cuts through 3/8" hemp and still have signifiant cutting ability left (100 AO finish, 12 degree edge), and cut 6 meters of cardboard (22 degree, fine ceramic microbevel) with a three inch blade before it will tear the cardboard.

There are much better blade materials of course, and the performance will be 10-100 times greater with high end tool steels, but even the low end blades can make more than a few cuts on soft materials. When the materials get harder then it changes and there is some cutting which can't be done with softer blades, Alvin has noted this on rec.knives on many occasions.

In general they are not what I would pick, but a lot of very well respected knives and knifemakers run fairly soft blades, even softer than CRK&T and others harden their AUS series. Randall being one of the oldest and most well know example who use a relatively low hardness.

-Cliff

 

[STR]

Tests I've seen show different results than yours Cliff. For example in one I know of 440C got 15 cuts in 1" manilla rope, 154 CM got 18, D2 got up to 30 before they were deemed dulled by the tester. Your results as are these are all subjective to the tastes of the user. When I tried this with some 1" manilla rope I bought at a yard sale I got results similar to the above. I"m sure with 3/8 the results would be markedly higher but statements like that as if fact generally scare me for a number of reasons. One no two people have the same idea of what sharp is or what dull is. But more importantly when a young person comes here new to knives and reads that even cheapo mild steel should make x amount of cuts before its dull or its defective and then that doesn't pan out in their own mind or experience it sets them up for a number of frustrations that can be prevented I think.

So, when I say AUS6 and 8 gets 10 to 15 cuts in it (the 1") before the effort gets to the point I deem it unworthy Im trying to say it is to the point "I deem it unworthy". Could I continue? Well sure but to me that was the point of where the edge significantly changed from effectively sharp to dulled enough to require much more effort for the same cut.

There is no defects in any of these blades and I know how to sharpen well enough to get paid for it so I have trouble believing I'm doing something wrong using the Edge Pro or one of the other systems I have here at hand.

STR

 

[STR]

I'll add that really we are talking about two different kinds of testing methods also. I'm not talking about taking the blade all the way to the point that it has about reached the very limits of its cutting ability but simply to the point that if you were say, wood carving that it would be time to touch it up because its no longer the pocket razor it was when you started. To the point effort increase is first noticed I guess is what I understood was the method used by most. Perhaps that is my err though.

I see why being a tester you would take it to the extreme but for me the effective edge I like to keep is that highly sharp (biting sharp) edge like the ones Spyderco is famous for. And as an example. I just recieved a brand new Salt 1 PE. It came as usual from Spyderco with a fantastically sharp factory edge that needed no attention at all out of the box. It was ready to go shaving sharp. I used it yesterday to cut fiberglass reinforced tape and regular clear tape to pack up six packages and two this morning to mail. Its no longer what I deem sharp and no longer takes hairs. So is it dull? Well to me yes. To you it may have 75 more cuts in it yet Cliff.

Steve

 

[Cliff Stamp]

Tests I've seen show different results than yours Cliff. For example in one I know of 440C got 15 cuts in 1" hemp rope, 154 CM got 18, D2 got up to 30 before they were deemed dulled by the tester. Your results as are these are all subjective to the tastes of the user.

The edge retention trials I run are not subjective, I don't judge the sharpness, I measure it numerically. The reason those steels did so poorly in the rope cutting was that they were either left burred, the steel was defective or the edge geometry and grit profile was not optimal, most likely it was the latter two. Mike Swaim noted in detail how these factors can influence cutting ability and edge retention signifiantly over ten years ago on rec.knives. Joe Talmadge showed numerically how you can induce changes of *hundreds* of percent easily. If you want to see how how extreme a result this can induce, see the review of the Mel Sorg utility knife and note that by altering the profile and grit finish aftering cutting 2046 pices of rope the knife was actually far sharper than after cutting 62 pieces initially.

One no two people have the same idea of what sharp is or what dull is.

Measure it, Alvin noted how to do this trivially with no subjective judgement with a piece of paper ten years ago on rec.knives, and he was saying it long before then, that was just when I first read it. Yes if novice users read the statements I made they are likely to be confused if they compared that performance to the stock profiles on most knives. However if they read the reviews it refers to they would not because it explains in great detail where the performances comes from. Which reminds me I should put in links to Mike's and Joe's commentary when I introduce the influence of geometry/grit finish.

I'm not talking about taking the blade all the way to the point that it has about reached the very limits of its cutting ability ...

Aside from the really abrasive work like carpet or digging in the ground, most edge retention comparisons I do like the cardboard and rope cutting are stopped well before the point at which the blades lose the ability to slice newsprint. It is rare for example for me to dull them to the point where you could not easily slice a tomato aside from as noted the really extreme high wear materials.

-Cliff

 

[STR]

Which reminds me I should put in links to Mike's and Joe's commentary when I introduce the influence of geometry/grit finish.

Yes and you should put links to all these things your recommend I read as well.

I have no idea what you are talking about or referring to most of the time with these names you throw out.

I don't buy that W&H do not know how to sharpen. The results of their test are pretty uniform so it seems to me the results are probably accurate. I do have trouble believing you sliced 128 cuts in 3/8" hemp rope and then sliced news print or a tomato cleanly though. You have that feat using mild steel on your site somewhere? Sounds like a Ginsu commercial.

The whole point of that test by W&H was to show how great ZDP steel was. It got 100 cuts in the 1" manilla rope vs 30 for D2. But to hear you that is trivial and even mild steel can exceed this. I don't buy it. I also don't believe there was anything wrong with any of the knives.

STR

 

[STR]

Oh, here is the link to that article where that test is mentioned. I found another talking about the same test that had more detail saying how all knives were the same model sharpened the same and tested but can't find it now. If I do I'll post it later also.

Something doesn't jive here Cliff. I can't see how you can have one tester saying one thing and another still a completely different thing and you not agree there is subjective judgement here.

These guys were talking about 100 cuts like it was a milestone and are wanting to test it again to see how far above that it can go and you say it is sharpened wrong? Is that what I'm to believe? I don't buy it.

http://www.williamhenryknives.com/press-awards/articles/ZDP.pdf

STR

 

[STR]

Well, as I said earlier I picked up about 75' of 1" hemp rope for $1.50 at a yard sale. So, I brought it in to test this out for myself.

The test knife was a brand new Spyderco Rescue 93mm PE in VG10 just opened that I just got in the mail. It was shaving sharp taking hairs off the top of my arm without skin when the test began. It had no burr and the edge was the usual exemplary one from Spyderco. Its a 15 degree edge based on what I can tell using the Edge Pro to check. I haven't resharpened it yet though.

Results on 1" hemp rope using a cutting board to cut on and cutting the rope like it was a sausage = 25 cuts and its duller than $hit. I forced another three and a half cuts before stopping the test at 28.5 cuts but it took so much force for those last three and a half that I feared if I slipped I'd be going to the ER tonight instead of making this post. After the test I tried to cut it using all my strength holding the rope folded over the edge. I'd be there at that all night long.

For the record. It won't slice news print unless you poke it in first and rip it down the middle and even then it tears and doesn't cut cleanly at all. If I had a tomato I'd try that and I may actually run to Wal-Mart just to get one to see if it will slice it or squish it before I resharpen.

Cliff their test for W&H is accurate on 1" manilla rope based on this test.

I used manilla rope last time I did a cutting test and frankly this time I am surprised that I got as many cuts as I did. This hemp rope is abrasive as all get out compared to the manilla. It really did a number on this blade in a hurry cutting the full 1" rope on a cutting board like a sausage.
STR

 

[STR]

Ok. Cliff in the light of being fair and giving the benefit of the doubt I did it your way also. My results are very similar to what you said you got using smaller pieces of rope and nearly identical to W&H using thicker pieces. I think we were both right but my test was with hemp rope and their was manilla. I'm not sure which is harder on an edge. Perhaps similar enough to be not worth mentioning.

In my second test I first sharpened the Rescue blade using the edge pro 220 grit stone at the green 18 degree setting. ( I was wrong on my first guess at the edge being 15) The 220 grit is all I used to bring the edge back. Once again it was shaving hairs off without taking skin and no burr was detected.

After sharpening I took out the rope and first separated it into the individual strands the 1" was made up of which were three smaller pieces entwined around each other. I think these are bigger than 3/8" and for that matter this may be 1.25" hemp rope. I am not sure.

Results are in and they are: 155 cuts after sharpening and I quit due to wearing a blistered raw spot on my index finger from holding the rope folded over the edge for each cut. The VG10 blade still has more cuts in it and still slices the thin Post office reciepts but not very well on news print. You can see the slice in the post office reciept sitting by the Edge Pro. It is pretty dull but I think I could easily hit 200 slices in the rope with this VG10 blade before it just became unbearable. Perhaps not but it would be close I think. I don't consider VG10 to be mild steel and I'm pretty sure hemp is more abrasive than manilla but could be wrong.

I would say if you want to conclude your tests faster in the future Cliff to just use 1" hemp rope or larger. It takes way less time that way than to cut smaller pieces over and over. Try it you'll see what I mean. In the end this proves to me that there was nothing wrong with the blades in the test by W&H and that they did not do poorly at all but did quite well actually considering the difficulty in cutting the thicker pieces on a cutting board vs these smaller pieces folded over the edge and pulling back with full leverage.

Same rope different sizes and they both show a big difference in the number of cuts and the significance of how dull the knife got during the test. The smaller pieces are much easier to handle but the bigger one dulls the edge much faster. It seems that cutting three times the thickness dulled it three times faster basically. I can appreciate the test results from W&H more now after doing this. Any steel that will cut 100 times in 1" rope of any kind is worth getting excited about for sure. There is no way you can say there was anything wrong with these knives in the W&H test or that they performed poorly.

STR

 

[Cliff Stamp]

I don't buy that W&H do not know how to sharpen.

Mike generally worked on more inexpensive knives, he started with machetes and similar and no one really judges them as sharp initially but Joe did the same to high end knives which are commonly praised for having high sharpness such a Cold Steel and Benchmade and improved them by *hundreds* of percent. Yes, the edges for rope cutting are far sub-optimal both in terms of angle and grit finish. Does this mean Cold Steel and Benchmade don't know how to sharpen, no you can't conclude that. A Ratweiler for example doesn't have an optimal wood cutting edge profile but does this mean Jerry Busse doesn't know how to grind one - no the data doesn't support that conclusion.

You have that feat using mild steel on your site somewhere?

It is in the reviews of the protoypes mild steel blades I ground as low end benchmarks. As I noted previously the reason the performance is so elevated is that the edge profile is optimized in angle and grit for the work. This isn't surprising given the work Mike did on really low end blades.

The whole point of that test by W&H was to show how great ZDP steel was. It got 100 cuts in the 1" manilla rope vs 30 for D2. But to hear you that is trivial and even mild steel can exceed this.

For perspective David Boye has done *thousands* of cuts on one inch hemp with one of his 440C knives. He uses a geometry and grit finish very much optimized for slicing rope which is why his performance is so elevated. I have noted in detail in the reviews showing the effect that this can make. Mike and Joe have done similar previously, this is a huge effect meaning factors of 10-1000 depending on how much you change the angle/grit.

I can't see how you can have one tester saying one thing and another still a completely different thing and you not agree there is subjective judgement here.

Their sharpness is subjective because they don't define the stopping criteria. I define mine so there is no subjective judgement involved.

These guys were talking about 100 cuts like it was a milestone and are wanting to test it again to see how far above that it can go and you say it is sharpened wrong? Is that what I'm to believe?

Yes, it isn't optimal for slicing rope.

Results on 1" hemp rope using a cutting board to cut on and cutting the rope like it was a sausage = 25 cuts and its duller than $hit.

Similar performance is noted in the reviews in detail for obtuse edges which have a high polish, that isn't an edge optimized for slicing hemp rope.

I think I could easily hit 200 slices in the rope with this VG10 blade before it just became unbearable. Perhaps not but it would be close I think. I don't consider VG10 to be mild steel and I'm pretty sure hemp is more abrasive than manilla but could be wrong.

Note you have shown an increase from tens to hundreds by just adjusting the grit profile and you are still not close to the limit of the geometry or finish of the mild steel blade I referenced.

I would say if you want to conclude your tests faster in the future Cliff to just use 1" hemp rope or larger.

With optimal edges and grit finishes it takes a massive amount of rope to significantly blunt an edge. You also have to repeat the cutting 3-5 times at least for stability (on different rolls of rope) to obtain a consistent average and include at least one other knife as a benchmark so you are looking in the range of 10 K cuts just to do *ONE* edge retention trial on one knife.

Multiply by 3-5 to examine the performance for different edge angles and grit finishes and you are literally in the 100 K range for number of cuts. Rope simply costs too much to make it practical. I mainly use it to benchmark cutting ability currently. If I found a big roll being thrown out of similar I'd use it of course, but one inch hemp is way too expensive to buy new.

Note when you get it used you are also getting random dirt and debris which greatly effect the results. This was brought up on Busse's forum awhile back where a user tried to duplciate the trials Busse has done live and got very different results because he was cutting used rope and the debris was actually way more abrasive than the rope itself.

If I want to do an edge retention trial in short period of time I just cut carpet, it dulls an edge 10 to 1000 times faster than hemp rope depending on how used it is and what type.

-Cliff

 

[Cliff Stamp]

Here are Joe's original benchmark articles :

http://www.knifeforums.com/ubbthreads/showthreaded.php?Number=33921

and

http://www.bladeforums.com/forums/showthread.php?t=90315

Note in the Axis he was at 700% and he is still nowhere near the limit of geometry and grit for rope cutting. Mike first introduced this in 98 :

http://groups.google.ca/group/rec.knives/msg/ba25406743c82aec?hl=en&

where he proposed that cutting ability *and* edge retention were increased at lower angles in some cases. He also explored the increase in cutting abilility and edge retention of coarse grit finishes in detail in many reviews :

http://groups.google.ca/group/rec.knives/msg/c5729f95dc253796?dmode=source&hl=en

Mike is still net active for those concerned, working with knives just isn't a current hobby which is a significant loss to the knife community.

-Cliff

 

[STR]

Carpet is a good idea. If I had not picked up this rope so cheap it would not have been possible to do a test like this. Carpet remnants are cheap and easy to find though. I do believe sharpening it improved it some in performance.

Now I am rebuilding the body of the folder though. The thing developed play from all the heavy handed cutting repeatedly leaning into it with a lot of my weight. The handle scales will be 1/8" thick bead blasted aluminum here before too much longer.

STR

 

[Cliff Stamp]

Used carpet is really wearing, it is a quick way to demonstrate to someone the edge retention of serrations vs plain edges. One thing to remember when using it for comparisons is that it is highly random due to the nature of the dirt. You don't want to for example make 50 cuts with one knife and then 50 cuts with another and compare. Rotate the knives very 5-10 cuts so on average they "see" similar material. If you do this a few times and average them the results are decently stable, getting a 5-10% spread isn't difficult with consistent sharpening.

-Cliff