M390 vs. M4 Rope Cut Test

[pnsxyr]

Depends on the rope really and how clean it is, but in general Manila Rope is pretty abrasive, much more so than cardboard on average...

@ Pnsxyr, I completely agree. M390 is absolutely amazing. Reference your question about the M4, idk what "batch" this is per se. I have had the knife about a year, but I'm not sure of the actual production date. As far as the rope, I like to use manilla because it is a natural fiber. As silly as it sounds, I buy the same brand from Home Depot every time. I try to keep it as "same" as possible, given that it is a natural fiber. I figure the same brand, from the same place, eliminates as many variables as possible given that it is a natural fiber. I WILL tell you this: the M4 and the M390 flat ran through this 50 feet of rope. I went through about 42 of so feet during this particular test. These steels flat cut!!

Bare with me guys as my steel understanding is not nearly as comprehensive as yours', and I am trying to expand my knowledge in interpreting results...

A test that uses a more abrasive material would be expected to see more pronounced results than a test using a minimally-abrasive material because the speed of deformation is going to be accelerated in steels with lower wear resistance, right? (for example, how a knife in AUS-6 or BD1 loses the razor hone after just cutting a few pieces of cardboard only to quickly lose the utility/working edge soon after, but something like M390, S90V, or S110V is practically not even effected and the edge itself doesn't even really deform much until someone has made many, many, many cuts of the same cardboard?)

That would explain why steels like M390 or S90V perform unusually well compared to other supersteels including those with much higher Rockwell Hardness, correct?

And the actual reason behind this is thanks to fine carbides that are better distributed and a carbide distribution that works favorably when cutting through materials that tend to deform edges by having tougher carbides to do the cutting?

Finally, in this case of both M390 and S90V, I am guessing the very high vanadium content is the major component as from what I have read it is a hard, tough element in which ideally it is dispersed among the edge over something such as chromium which is not as robust? (sorry for all the questions!)

 

[Ankerson]

Are those actual numbers or examples? Which knives were used if it is the former?

Those are actual production knives in the 2nd set, the 1st was just an general example of how things can really be, I have seen them that far apart before.

K390 MT and VG-10 Stretch.... Actual knives....

 

[Ankerson]

Your insinuations of an agenda are misplaced. No one thinned anything to the point of failure. I took stock thickness production knives, rebeveled them to fit the Sharpmaker, sharpened them, repeated VB's tests, and found lower end steels could make the same number of cuts in rope and still slice paper as some upper end steels, even with thicker geometries. That's it. The answer to my question was yes, lower end steels can make the number of cuts VB posted and still pass the test of slicing paper. I haven't gone to 900 yet, but eventually I'll try it.

NOT TALKING about you.

Speaking in general terms only here....

 

[Ankerson]

Bare with me guys as my steel understanding is not nearly as comprehensive as yours', and I am trying to expand my knowledge in interpreting results...

A test that uses a more abrasive material would be expected to see more pronounced results than a test using a minimally-abrasive material because the speed of deformation is going to be accelerated in steels with lower wear resistance, right? (for example, how a knife in AUS-6 or BD1 loses the razor hone after just cutting a few pieces of cardboard only to quickly lose the utility/working edge soon after, but something like M390, S90V, or S110V is practically not even effected and the edge itself doesn't even really deform much until someone has made many, many, many cuts of the same cardboard?)

That would explain why steels like M390 or S90V perform unusually well compared to other supersteels including those with much higher Rockwell Hardness, correct?

And the actual reason behind this is thanks to fine carbides that are better distributed and a carbide distribution that works favorably when cutting through materials that tend to deform edges by having tougher carbides to do the cutting?

Finally, in this case of both M390 and S90V, I am guessing the very high vanadium content is the major component as from what I have read it is a hard, tough element in which ideally it is dispersed among the edge over something such as chromium which is not as robust? (sorry for all the questions!)

In general terms that is how it works, usually.

But sometimes variations can effect things... So not everything is 100% all the time.

 

[ninjaminibear]

My M390 Para 2 is probably my favorite knife!

Where on earth did you get an M390 Para2?!

 

[Strong-Dog]

Where on earth did you get an M390 Para2?!

Probably from bento box shop

 

[Battle Proof]

Cool test and thank you. Great discussion.

Thanks for sharing.

Battle

 

[Jibbles]

I just went ahead and skipped through all the wiener-waving in this thread.
Thanks for the test/writeup. Much appreciated.
However, I take these tests with a grain of salt since 10 different people would probably get 10 different results lol. Personally, M4 is probably my favorite. Though my experience with M390 is limited, I do have a little more time using CTS-204p (most similar steel I own I think) and M4 just does it for me. It feels almost soft (for lack of a better term) when sharpening. Almost reminds me of 154cm in terms of it's ease of sharpening. It's just a pleasure to sharpen as far as supersteels go (albeit sharpening doesn't happen that much).
Also, M4 seems to have a nearly unbelievable balance of edge-holding ability, and toughness. With my GB I've inadvertantly gone through those mondo industrial staples, wire, and even a metal binding strap and the edge didn't chip in the slightest. Hell, it didn't even have a roll or a burr I could feel. I literally hit it on my Sharpmaker UF rods and it keeps on popping hairs.
In short, all these fancy-schmantzy steels are stellar. All I'm saying is I challenge someone to find something south of 3V and A2 that holds a respectable edge and is as tough as CPM-M4. It's definitely a very special steel in my eyes.

 

[evosbu1]

So is the CPM-Cruwear a bust?

I read on Crucible's website that the HRC can be from 61-65, though I'm clueless about what Spyderco does with it. Even so, wasn't the hype of the CPM-Cruwear Military based on it possessing an edge as resilient as S30V but without the brittleness of S30V and D2?

 

[Ankerson]

So is the CPM-Cruwear a bust?

I read on Crucible's website that the HRC can be from 61-65, though I'm clueless about what Spyderco does with it. Even so, wasn't the hype of the CPM-Cruwear Military based on it possessing an edge as resilient as S30V but without the brittleness of S30V and D2?

Haven't ran it yet, I have a Military in CPM Cru-Wear, I believe Spyderco ran it in the 61 RC range.

 

[The Mastiff]

So is the CPM-Cruwear a bust?

I read on Crucible's website that the HRC can be from 61-65, though I'm clueless about what Spyderco does with it. Even so, wasn't the hype of the CPM-Cruwear Military based on it possessing an edge as resilient as S30V but without the brittleness of S30V and D2?

Having a lower score based on one kind of test of one of the steels attributes doesn't mean bust. I suppose what you are saying is yes, it should take thinner edges and be tougher than S30V in both shock and edge stability. In certain kinds of cutting this means greater scores than thicker geometries and lower strength steels. The rope tests at the same geometry and grit aren't looking for that though. They look for pure abrasive wear resistance which does favor more and harder carbides. Not better or worse to me though maybe to some others. We all have different needs and likes. In some types of cutting like talked about by me2, steels like W2, and 52100 might be "better". Is a car better than a truck? Sometimes, yes. Sometimes, no.

 

[JNewell]

Having a lower score based on one kind of test of one of the steels attributes doesn't mean bust. I suppose what you are saying is yes, it should take thinner edges and be tougher than S30V in both shock and edge stability. In certain kinds of cutting this means greater scores than thicker geometries and lower strength steels. The rope tests at the same geometry and grit aren't looking for that though. They look for pure abrasive wear resistance which does favor more and harder carbides. Not better or worse to me though maybe to some others. We all have different needs and likes. In some types of cutting like talked about by me2, steels like W2, and 52100 might be "better". Is a car better than a truck? Sometimes, yes. Sometimes, no.

Please reconsider. This is the internet. You are being way too open-minded.

 

[The Mastiff]

I'll quote Sal on this one. It's difficult to argue with.

"All good, just different". Steels, Ice creams, Beer, women, etc.... :0

I gladly defer to guys who do real testing though. Jim knows more about true "super steel" class steels due to testing and use than most. He has worked with a lot of big name makers who want to stay unmentioned as well. I don't argue with him about these steels.

I have 40 some years of knife experience myself and prefer tool steels and HSS's. Guys like Me2 know more about their kind of work than I do though, but it's a totally different type use from what Jim does and don't see any conflict in what they find. Vegas has been getting results that I could have guessed closely at so he seems to be doing things right too.

The only arguments that get on my nerves are slogan based like "Busse's best!", "nuff said". Just repeating things someone else says without having any original thought is what gets the least respect from me. If their use truly finds Busse best for them no problem. To go tell a new knife user here to learn that though as if it is some kind of absolute truth is just plain wrong.

Other than that I'm pretty open minded. Oh yeah. Except when people tell others "440C used to be THE super steel!" Everybody knows 440C is evil!!!

*cough*

 

[jmarsh667]

I don't recall any confirmed report that Spyderco made a conscious decision to change the hardness for CPM-M4. The first run of Bradley folders were accidentally run at 64-65. There was discussion about subsequent production being run lower but it's never been confirmed one way or the other, as far as I know. One of the M4 Mules tested at 62.5. I don't have any test reports for the Military M4 blade at my fingertips but I think you can assume it's in the 62-63 range.

Just thought I'd mention I have a newer Gayle Bradley and it was RC'd @ 65.8-66.2 if that will clear up any confusion. I personally don't think spyderco changed anything or lowered the hardness. If anything they may have brought it up a tad knowing they could.