CPM-S35VN and CrimsonTideShooter test

[Ankerson]

I've been trying to catch up on everything that's been posted both here and the other forums. It's an interesting phenomena.

What I'm referring to is the explosion of posts and worry over very few incidents that we don't have the reasons for yet.

I'm glad Cliff, and Jim have posted here already. CTS has been doing a bunch of posting and unfortunately was getting flak for it on a different forum including by a guy who did a test of his own, admittedly had a tiny roll, but attempted to use it as evidence to refute others results. I'm not going to get into the subject of what other manufacturers say on their forums in the Spyderco forum. Sal is a class act and doesn't deserve to get involved in cross forum wars or hard feelings resulting from such stuff. :)

I don't really see anything going on here that surprises me with the steel or knives. The knife was made to roll, not chip. It seems to be doing exactly that. If it has been too easy than get the knives into the labs so we can see what the heck's going on and get it behind our knife community one way or another.

I see nothing that will keep me from ordering the Native 5 in these results. If I was to have a problem with it, just like any other QC problem I'd get it resolved with no added drama. To be honest I'd rather have a knife that rolls it's edge than a bunch of needless drama. For me these knives are a hobby and relaxation rather than adding problems to my life.

As far as S35V goes I'll make this offer. If anybody that actually makes knives and has the proper heat treat equipment ( no barbecue grills please nor home made propane ovens with no temp control other than eyeballing colors. These need very real precision heat treats.) for these very sophisticated highly alloyed steels and wants a free piece of S35VN to try please PM me. It's a bad year for me and unfortunately I'll have to ask for money for shipping. I'll be getting some water jet cut along with some other steels for future projects and I'll cut a few extra pieces in case. This might take me a couple of months but I'll get it to you. Please e-mail me at mastiffone@hotmail.com.

Yep, I'm a cruware/super blue/52100 /O-1/3V guy but I still edc knives in S30V, and have found them good performers. I suspect in time we will be saying as much for S35VN. If not? Well, there's plenty of more great cutlery steels available and for everybody here there is one just suited for you.

Recall all the silly claims about S30V conspiracies and please keep the now ridiculousness of those statements in mind when getting caught up in this flurry of posts about 3-4 incidents of unknown causes? Note please that we do have believable reports of what I'd call very good performance by an engineer/mod on another forum who found no edge damage on rope after his testing. I also know how well my mule performed for me.

Yes, and please don't give me a history lesson on S30V and what was said, and not said. I was there for that and have my own viewpoint on it. I'm not much into conspiracy theories.

A lot of the tech stuff and guesses have been covered here and elsewhere and I don't have the time and energy to go over all of them point by point, nor repeat my own postings to hear myself talk.

I will repeat the offer to find out for yourself with a spyderco under warranty, or a roll your own with some annealed , thickness about .180 which I can provide.

Joe/Raleigh

Yeah John got a lot of unfounded flack over his testing, that was the reason why I jumped all in this because the method is good and it was a good honest test.

I will post here what I posted over there.

All steel will fail at some point, it will either chip or roll, but one or the other will happen in the end with any steel. It how fast the edge rolls or chips that really makes the difference. What got my attention was how fast the edge rolled on the CRK blade, not so much the Native 5 as it really didn't look that bad in the video.

That is why some of us do the testing to see how a steel holds up in cutting, how long and what the edge does, we do test the knives to that point of what I call normal wear and tear happens.

Shiny spots and maybe some rolling and or slight chipping is NORMAL when we push the knives to the point were the steel just can't take it anymore by doing enough cutting.

[wquiles]

All steel will fail at some point, it will either chip or roll, but one or the other will happen in the end with any steel. It how fast the edge rolls or chips that really makes the difference. What got my attention was how fast the edge rolled on the CRK blade, no so much the Native 5 as it really didn't look that bad in the video.

Total newbie here: From what I gather after reading and watching those videos is that the edges being tested flat ground as in figure #2 below (although some folks do sometimes do a micro-bevel as in #5 below). Wouldn't a convex edge (as in #6), even if not as super-sharp, perform a little bit better for "hard" use and/or in aggressive cutting such as shown in those videos, as the edge would have more metal behind it and therefore harder to get the edge to roll/chip?




Will

[Ankerson]

Total newbie here: From what I gather after reading and watching those videos is that the edges being tested flat ground as in figure #2 below (although some folks do sometimes do a micro-bevel as in #5 below). Wouldn't a convex edge (as in #6), even if not as super-sharp, perform a little bit better for "hard" use and/or in aggressive cutting such as shown in those videos, as the edge would have more metal behind it and therefore harder to get the edge to roll/chip?




Will

NOPE, it doesn't work that way in FOLDERS.

Convex edge will make no difference at all in how strong the edge is in slicing and cutting compared to a V edge.

In a true convex edge you are thinning out the edge even more so if anything the edge will have less strength in the end to a comparable V edge with the same angle.

It works well in choppers because the edge angle can be increased and once the shoulders are knocked off it will work better.

[Cliff Stamp]

How about 300 cuts on orange 3 wire power cord and still shaves hair, that's S35VN at 58-59 RC.

I cut a bunch of electrical cord years back, copper is very soft metal, provided you can restrain it to a compressive load it isn't a problem, but the tricky part is not snapping the edge while in the copper. I did not like it as a testing medium as you can do one bad cut which would have more of an effect than the 50 vertical cuts before it. I would not whoever did that, assuming they are not using a jig/load, has some impressive vertical control in the cutting.

The knife was made to roll, not chip.

Yes, but the cutting which is causing rolls is soft material, the steel should not roll significantly on ropes and cardboard. But again, this can not be a hardness issue, claiming it is hardness is just as bad as claiming the steel doesn't have enough pixie dust in it.

There is no significant UTS difference in steel at 59 vs one at 60 HRC, the variance in cutting would be an order of magnitude beyond that difference. 9 chances out of ten, if the effect is repeatable it is evidence of high levels of retained austenite and/or a blown grain.

I will however repeat again, the random nature of rope cutting means that quite a few trials have to be done and the MEDIAN of the results used as an indicator of performance. If you compare one shot results, or pick extreme data points then you are doing nothing but spreading misinformation because the results you are claiming are unstable.

All high carbide steels are prone to random and edge isolated sudden blunting due to the completely random nature of the breakout of the carbides due to the segregation. Just consider this :



Now draw a line through this, sometimes you hit big pieces of carbide sometimes you don't. That is what happens when you sharpen, and in the places where you hit big pieces and they are towards the bottom they tear out and leave flat spots in the edge. More clearly :



That is an edge cross secton (N690), now imagine sharpening that blade a few times. It is immediately obvious the results are not going to be the same at that point on the edge because some times it hits carbide, some times it does not, and some times it hits a huge piece of carbide.

There is also no way, given the makeup of S35VN that is it significant more prone to edge deformation than S30V, it is in fact inherently more edge stable not less. Claiming otherwise is like arguing that 1095 has better corrosion resistance than 440C.

To be very blunt, if you polled the user group of experience with S35VN, it would be expected that you would find reports of premature blunting for reasons described in the above. If the reports start to dominate user feedback then it would be a cause for concern.

If a maker had extreme levels of concern for performance they would contact the individual with the reported low performance and see if they could determine if it was within the normal spread of results or there was an issue with the blade.

[lychesko]

In all it is possible to find the reason but the fact it is necessary fact.what for to pay 200$ for a knife if it works as that that for 50$???(native 5--delica4) What for to tell about different edges now-it it was necessary to do much earlier to a batch production... And now it is necessary to establish the reason.thanks sal!!!
I want to be assured of quality of a steel instead of to buy at random only time have told that it is a good steel...

[Ankerson]

I cut a bunch of electrical cord years back, copper is very soft metal, provided you can restrain it to a compressive load it isn't a problem, but the tricky part is not snapping the edge while in the copper. I did not like it as a testing medium as you can do one bad cut which would have more of an effect than the 50 vertical cuts before it. I would not whoever did that, assuming they are not using a jig/load, has some impressive vertical control in the cutting.

I also used it back along time ago and it really sucked for me too, and I had to do some cutting on cord for work ect and it would just kill the edges.

One would have to push it for sure, a draw cut would kill the edge in a real hurry.

Wire cutters are the ticket for sure.

[lychesko]

The manufacturer of the test confirms that all other knifes have consulted well with this work namely s35vn him has unpleasantly surprised
.maybe it says lies or the reason in one copy I don't know...

[sal]

The argument for consistency for sure. Tilting the knife by a slight twiist of your wrist would be a strong variabe. The CATRA clamps the blade vertically and clamps the cutting medium as well so there is no cutting board involved.

sal

[Ankerson]

The argument for consistency for sure. Tilting the knife by a slight twiist of your wrist would be a strong variabe. The CATRA clamps the blade vertically and clamps the cutting medium as well so there is no cutting board involved.

sal

I still think CATRA is the most consistent way to test because the biggest variable is removed, that would be the human element. :)

We still need real world testing for another data point though.

[lychesko]

native 5 a good knife... There are thoughts to make in other super steels CTS20CP s90v ore others???

[TrojanDonkey]

Maybe this is off topic but here goes. I work for a polymer company and cut polymer with different types of blades and steel daily.I have had lesser steels dull/roll quicker than softer steels when they were sharpened very sharp/shallow angle.It is amazing the difference the angle can make.Scary sharp edges with good steel rolls quicker than the less sharp tubing cutters you can buy at home depot with the cheap carbon steel blades.Some plastics/polymer are easy to cut(FEP and Teflon).Teflon is self lubricating so even though it is strong blades glide smoothly thru the material.Some proprietary polymers(aerospace industry)is so hard I ruined my edge on my serrated Endura in seconds.I had used it for other polymers for months just stropping every week with a polished leather shoe string.Seeing how Spydercos and other high end knives are sooooo sharp it does not surprise me the edges will dull quick on VERY hard items.Some plasitics I work with are much harder than most wood you whittle on.In my real world use I have found PEEK plastic is **** on an edge.Also wet denim yarn will destory an edge real quick.Dry denim ropes were much easier on the edges of blades.Wet it it and it would was much harder on the knives. I was surprised by the difference.Oh yeah wet yarn was stronger in regards to vertical strength.Anyone who worked at a cotton mill can tell you that.Super thin edges just are not as tough as a thicker dull edge.Again maybe it has nothing to do with the subject in question.Just my observations. Bolt cutters are not scary sharp but hold up good.They may not cut paper or rope cleanly . That Xbox plastic and wire may be very hard-I dont know.

[JNewell]

Excellent explanation and pictures...question: what is the science of how hardness relates to the number and size of carbides in the steel?n Are all elements in the steel more or less equally affected by hardening (I doubt that?), or are some more affected than others? What's the real life effect on the edge and edge performance?

I cut a bunch of electrical cord years back, copper is very soft metal, provided you can restrain it to a compressive load it isn't a problem, but the tricky part is not snapping the edge while in the copper. I did not like it as a testing medium as you can do one bad cut which would have more of an effect than the 50 vertical cuts before it. I would not whoever did that, assuming they are not using a jig/load, has some impressive vertical control in the cutting.



Yes, but the cutting which is causing rolls is soft material, the steel should not roll significantly on ropes and cardboard. But again, this can not be a hardness issue, claiming it is hardness is just as bad as claiming the steel doesn't have enough pixie dust in it.

There is no significant UTS difference in steel at 59 vs one at 60 HRC, the variance in cutting would be an order of magnitude beyond that difference. 9 chances out of ten, if the effect is repeatable it is evidence of high levels of retained austenite and/or a blown grain.

I will however repeat again, the random nature of rope cutting means that quite a few trials have to be done and the MEDIAN of the results used as an indicator of performance. If you compare one shot results, or pick extreme data points then you are doing nothing but spreading misinformation because the results you are claiming are unstable.

All high carbide steels are prone to random and edge isolated sudden blunting due to the completely random nature of the breakout of the carbides due to the segregation. Just consider this :



Now draw a line through this, sometimes you hit big pieces of carbide sometimes you don't. That is what happens when you sharpen, and in the places where you hit big pieces and they are towards the bottom they tear out and leave flat spots in the edge. More clearly :



That is an edge cross secton (N690), now imagine sharpening that blade a few times. It is immediately obvious the results are not going to be the same at that point on the edge because some times it hits carbide, some times it does not, and some times it hits a huge piece of carbide.

There is also no way, given the makeup of S35VN that is it significant more prone to edge deformation than S30V, it is in fact inherently more edge stable not less. Claiming otherwise is like arguing that 1095 has better corrosion resistance than 440C.

To be very blunt, if you polled the user group of experience with S35VN, it would be expected that you would find reports of premature blunting for reasons described in the above. If the reports start to dominate user feedback then it would be a cause for concern.

If a maker had extreme levels of concern for performance they would contact the individual with the reported low performance and see if they could determine if it was within the normal spread of results or there was an issue with the blade.

[sal]

We still need real world testing for another data point though.

We cannot do without "real world" testing.

sal

[gull wing]

I guess this is why I keep buying Spyderco. :spyder:
The knowledge base here, wow.

[CrimsonTideShooter]

Hey Cliff, Sal, and Jim. I just did another rope test with a slightly thicker edge just to see if it made a difference. Still flattened fairly early on, unlike most other steels. Didn't perform all that badly though. I tried to get the best close ups of the edge as possible.

Cliff, I wrongly stated in the video that 1 point of hardness can make a huge difference. That was before I read your post above. Thanks for the education. :)


http://www.youtube.com/watch?v=JXJWaFk97FQ

[lychesko]

CrimsonTideShooter thanks for test!!!

[jackknifeh]

The rope cutting test looked to be pretty straight forward with a polished edge cutting on a cutting board and 3/8" rope.

Although it's a different cutting method than I use when I cut rope I don't see anything odd about the method.

Has any consideration gone into the effect of the cutting board on the edge? A cutting board shouldn't damage an edge. Good cutting boards are designed to cut food normally and leave the edge in good shape. However, these tests are getting into a level of performance that normal knife users might not think about. Everything that has an effect on the edge should be considered. I usually cut rope using a loop to insert the blade in and pull. For testing however that would use up at least 10 times as much rope for the same number of cuts so a board is needed. I guess as long as the same method is used it's ok. I mean right down to the same cutting board type being used. Just a thought.

Jack
Edit: I just watched some of a video by jdavis doing a second test of a Native5 and mentioning consistancy of the rope. He was talking about rope from the same roll. Now, if you are considering testing conditions being that consistant I believe the testing is MUCH more accurate than normal EDC usage. Hats off to jdavis for trying to be that accurate. Also, another hats off to him for all the videos he does. I think I get about 3 emails a day on new videos he's done. That's a lot.

[Ankerson]

Hey Cliff, Sal, and Jim. I just did another rope test with a slightly thicker edge just to see if it made a difference. Still flattened fairly early on, unlike most other steels. Didn't perform all that badly though. I tried to get the best close ups of the edge as possible.

Cliff, I wrongly stated in the video that 1 point of hardness can make a huge difference. That was before I read your post above. Thanks for the education. :)


http://www.youtube.com/watch?v=JXJWaFk97FQ

John,

Actually your were correct, HRC hardness can and will make a difference in the edge strength, as in rolling and or chipping. So if the edge is rolling to fast a bump in HRC hardness will slow that down.

The hardness can be adjusted until a medium is reached or say at 58 RC the edge rolls like crazy and at 63 it chips. So adjusting the hardness someplace in the middle would be the answer. That answer would be found with testing to see what hardness would give the best balance of performance.

Not sure what Cliff was really trying to say... Wall of text there.

Jim

[Ankerson]

Has any consideration gone into the effect of the cutting board on the edge? A cutting board shouldn't damage an edge. Good cutting boards are designed to cut food normally and leave the edge in good shape. However, these tests are getting into a level of performance that normal knife users might not think about. Everything that has an effect on the edge should be considered. I usually cut rope using a loop to insert the blade in and pull. For testing however that would use up at least 10 times as much rope for the same number of cuts so a board is needed. I guess as long as the same method is used it's ok. I mean right down to the same cutting board type being used. Just a thought.

Jack
Edit: I just watched some of a video by jdavis doing a second test of a Native5 and mentioning consistancy of the rope. He was talking about rope from the same roll. Now, if you are considering testing conditions being that consistant I believe the testing is MUCH more accurate than normal EDC usage. Hats off to jdavis for trying to be that accurate. Also, another hats off to him for all the videos he does. I think I get about 3 emails a day on new videos he's done. That's a lot.

The rope being cut is harder on the edge than the cutting board is.

[CrimsonTideShooter]

John,

Actually your were correct, HRC hardness can and will make a difference in the edge strength, as in rolling and or chipping. So if the edge is rolling to fast a bump in HRC hardness will slow that down.

The hardness can be adjusted until a medium is reached or say at 58 RC the edge rolls like crazy and at 63 it chips. So adjusting the hardness someplace in the middle would be the answer. That answer would be found with testing to see what hardness would give the best balance of performance.

Not sure what Cliff was really trying to say... Wall of text there.

Jim

Ahh ok thanks Jim. I thought that what I said was correct, but after reading the above I was questioning myself. Thanks for clearing that up. :)

About the test. The edge flattening was mitigated some, but not completely.