CPM S30V - Where is my wear resistance?

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sircantaloupe

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I recently got a new Spyderco Military. I was pretty excited, this was my first knife in S30V. Previously, I've used and sharpened carbon steel and Aus-8 pretty much exclusively. Now, I've heard a lot about S30V and it's wear resistance, but I'm fairly certain my expectations were not too high here.

Reprofiling the factory edge to a convex and getting the edge to hair popping sharpness took me no longer than 30 minutes. And I was several beers deep at the time. That's the fastest I've reprofiled an edge, ever. Maybe I'm getting better at sharpening, but I expected it to take a lot longer. After using it for the last week or so, what I've seen is edge retention about on par with my Aus-8 RAT-1, cutting cardboard. Frankly, I want to say my RAT-1 does better, but it's too early to reach that drastic a conclusion.

Just not what I expected.
 
First, the millie is not a knife I would convex.

Second, 99% of knife users will never push the steel far enough to tell a major difference. You need to push it way past the loss of shaving sharpness to see what it can really do.

How thin is your convex? how high of a finish grit? polishing some of these steels too far will reduce their performance.
 
I convexed it because that's the only way I've learned to sharpen. I know, I need to branch out a bit. The convex was made at aproximately the factory angle. Not too thin, it's sharpened on a JRE block using a decent amount of pressure. I did polish it the first time around, got super sharp but lost the edge quick. The most recent touch up, I went up to 600 mesh and then stropped it a bit. That got it pretty sharp but again the edge is back to not quite push cutting paper but not shaving.
 
CPM steels do what I call the chainsaw effect, as the dull they become very toothy and coarse. This is actually a good thing but most of us want a razor sharp edge to last and that's just not how they work.

If your new to these steels it will also take a bit to learn proper sharpening, I had issues with my first CPM steels too. Using a regular steel then moving to a high performance steel is a learning curve in itself.

It might also help to use diamond compound to strop with (no less than 1 micron) other compounds will work but IMO are not very effective.

To see its true performance cut drywall, carpet, cardbard, and some rope then slice a tomato. The edge will be plenty dull by most standards but still cut, its something that almost makes you scratch you head when you see it.
 
Caveat - I can neither verify or disprove this as I have not done any testing myself - please don't shoot the messenger

According to Michael Black in this month's KI (June 2010) - S30V is one of those steels that improve with age.

I don't know how he store it or whether cycling it thru a few seasons is what does the trick but he says that cutting performance on some of his S30V blades have increased tenfold over time
 
I was messing around with my ZT-0350 (S30V) yesterday. I had used my Lansky to reprofile it a while back (took a while), and since then I've spent a few minutes every couple or three days just lightly stropping it, first with green compound on leather, then with bare leather alone. The bevel is very polished & shiny, looks great. At times, it'll just approach hair-whittling or occasionally tree-topping. But I've noticed it won't stay there very long. It still shaves, but not to the same degree as most others I've given the same treatment.

The odd thing is, when cutting other stuff, it's as if there's no degradation in performance at all. When I was fiddling with it yesterday, I picked up a junk mail newspaper that was laying around, and rolled it up tightly to about 1" diameter. I then cut the paper 'stick' in half with a quick slash of the knife. Took each piece of the rolled up paper and cut again, and again, and again. I then compared the shaving sharpness to what I'd seen before I cut the paper. Prior to the paper-cutting, the shaving sharpness was what I'd call only fair. Afterwards, the edge seemed to grab the hairs a little more aggressively. Seemed to have a little more 'bite'. This sounds very much like the 'chain saw effect' mentioned by knifenut1013 earlier. Very odd, but at the same time, kind of encouraging about what this steels seems to be able to do with certain applications.
 
antonio_luiz said:
Caveat - I can neither verify or disprove this as I have not done any testing myself - please don't shoot the messenger

According to Michael Black in this month's KI (June 2010) - S30V is one of those steels that improve with age.

I don't know how he store it or whether cycling it thru a few seasons is what does the trick but he says that cutting performance on some of his S30V blades have increased tenfold over time
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Really, that sounds like bunk, you'd be seeing "aged" s30v knives in the market if there were a hint of truth to it.

I don't know Michael Black, but unless he's got proof, he's full of it.
 
Skimo said:
Really, that sounds like bunk, you'd be seeing "aged" s30v knives in the market if there were a hint of truth to it.

I don't know Michael Black, but unless he's got proof, he's full of it.
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I've read the same thing in a few articles in different knife mags. It wasn't specific to S30V steel, but almost all steels, mainly carbon steels. I was very surprised, there may be some truth to it.
 
Knifenut and Obsessed are right on. S30 is kind of hard to get sharp- especially super sharp, and the wear resistance you are looking for only comes into play after it loses that initial edge, which it does pretty quickly. The way I would describe it is that it doesn't "feel" sharp for long, by whatever means you use to feel it, whether it be with your thumb, or shaving, or cutting paper. However, it will keep on cutting surprisingly well for how dull it feels.

For me ceramic rods work best to sharpen it to a decent shaving edge the quickest, but trying to get it sharper is almost pointless, and it is in this way that convexing may not be as efficient for touching up. It's perfectly fine as an edge profile as long as your hitting the edge with your sticks. You'll get significantly less chipping at 40*, which works against it again in keen-ness.
 
myti32, obsessed with edges & knifenut10-13 thanks a ton. i have'nt had a s30 for many yrs.have a millie on the way & am glad i wo'nt waste my time doing a super mirrow polish. i'm going to stop at the white spyderco unless some better info comes down. what about stropping on undressed leather? thanks dennis
 
DennisStrickland said:
myti32, obsessed with edges & knifenut10-13 thanks a ton. i have'nt had a s30 for many yrs.have a millie on the way & am glad i wo'nt waste my time doing a super mirrow polish. i'm going to stop at the white spyderco unless some better info comes down. what about stropping on undressed leather? thanks dennis
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I'm not yet sure that polishing the bevel on my S30V was wasted effort. I pursued that project with the goal of learning something new about S30V, and about sharpening & stropping in general. It didn't disappoint in that regard (wow). Very different experience from the others I've done thus far (1095, 420HC, VG-10, D2). I hear there's some value in a high polish, from a corrosion-resistance standpoint. And I've noticed that a nicely polished bevel is much easier to 'feel' on the strop (it gets very SMOOTH & slick feeling when the angle is just right).

And I do strop on bare, undressed leather too, usually after I strop on leather w/green compound. On S30V, I think the benefit is very subtle, but if I'm really ON my game, so to speak, I still think I can see some benefit to it. And, what the heck, it keeps me in practice. Find it very relaxing too. :)
 
I've always had trouble with my Native. Less now that it lives in its box and I EDC my D4...
 
Your wear resistance is still there, but, as was said above, you won't get the advantage of it until you push the knife well past the point it stops shaving. Think of edge holding as happening in 2 different stages. The initial hair shaving edge will generally last a relatively short time. The ability to hold this edge depends mostly on hardness, not wear resistance, as the main way this edge is lost is through edge rolling or deformation, not wear. After this, a working edge will last a long time, depending on steel. Wear resistance comes into play much more at this point. These edges won't pop hair off your arm, but they will cut most things for a very long time. Try sometime to see how much cardboard you can cut before the edge looses its ability to slice paper. Not push cut, but slice regular typing paper. Even the cheap steels will cut for a long time. A graph of edge sharpness looks like a ski slope. When very sharp, the edge dulls fairly quickly, like the beginning steep part of a ski slope. As the sharpness passes a certain point, you're in the second stage of dulling and sharpness loss slows down a lot. This is the flat part of the slope where you slow down to start the climb back to the top.

This is the problem with testing edge holding and comparing your results to someone elses. Standards vary a lot. You have to know what your stopping point is and what other peoples are. I have never seen the need for a S30V blade, because I prefer more ability to hold a very sharp edge. I have a home made knife that will still treetop hair off my arm after cutting the same amount of cardboard that reduces other knives to paper slicing sharpness. The difference is that knife has both high wear resistance and very high hardness, 64 HRc+, so it holds it edge well in both stages of dulling.
 
I've noticed some of these same mentioned characteristics with my experiences using
S30V . Yes, it loses that real nice sharpness fairly quick then settles into a good working edge and will finish say the field dressing of a large Elk of 850 lbs.. At which time begans to give a 'sluggish' edge but will still cut requiring more muscle . Its at this point that I don't like its cutting abilities and touch it up usually on a small X-fine diamond stone . Which it responds well to and will last a good while . Now, taking up with what Me2 was saying: There are other steels that will do the same as this (ATS-34)(field dress a bull elk). Then become dull and you KNOW they need sharpening as they stop cutting . They both arrive at the same point and need sharpening cutting about the same work load . I'd be hard pressed to note any difference in two different steels up to this third level and I'd sharpen both at that point anyway . So, to me there is some selling hype and consumer driven market trends afoot . Most guys if you handed them two knives with no steel markings on them could not identify the steel during use . Perhaps get closer to ID it during sharpening . This is why I'd rather just have a decent high grade steel that was easy to sharpen than the vanadium steels . DM
 
This is why I don't care too much for steels anymore. Especially since you're cutting cardboard. Cardboard is going to dull any steel very quickly.

Here's an oddball phenomenon I've run into: I just got a new FFG Delica with VG-10 steel. I've had VG-10 Delicas in saber grinds, flat grinds, and even a Delica in ZDP-189.

This new Delica has been holding an edge now for 2 weeks (1 extreme box cutting session per week and cutting up some small boxes every other day or so.) This is longer than any other steel I've tried, including the ZDP-189 Delica (which snagged HORRIBLY and was practically unusable on cardboard at the end of one extreme box cutting session, every time.) The funny thing is that I have another VG-10 Delica with a FFG blade (whose edge angle is even thicker, if I might add), and it never held an edge quite as long as this new one.

So to me, steel is a strange thing. I don't put too much thought into it anymore like I used to.

sircantaloupe said:
I want a knife that will hold it's shaving edge for a long time.
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If you're cutting cardboard, I don't think you're ever going to find what you're looking for. Unless some company starts producing blades made of adamantium...
 
THG, Your right on !! I've noticed this as well . When I find a knife that cuts well and has decent steel, I stick with it . The edge profile has much to do with it . DM
 
David Martin said:
The edge profile has much to do with it . DM
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That's the weird thing, though. My ZDP D4 had the thickest edge, and it didn't hold an edge very well. My brown D4 in VG-10 has an obtuse edge for being a FFG, but it doesn't hold an edge as well either compared to this new FFG D4 I just got.
 
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