Which common knife steels CANNOT get "scary" sharp?

Kaizen1

Kaizen1

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Over the past couple of years since I've been a part of this forum, I've occasionally come across posts where people make comments on how this or that steel can't get very sharp. I would read things like "It (whatever steel) can't get very sharp, but it'll hold a working edge forever". Since joining, I've developed my sharpening skills to a respectable level thanks to all of the sharpening geniuses on the M,T&E forums. I'm able to bring my edges to what would've been very impressive to me before.

So how do we define "scary sharp" for this thread? I'll leave this open to the individual who wants to post, but in general, I'm thinking about if it can split hair, shave without touching the skin or push cut newspaper. For most of the knife community from what I've been reading since I came to these forums, this is generally thought of as "scary sharp".

I bring this up because I haven't come across a commonly used steel that I haven't been able to bring to these levels of sharpness. And because of that, it's seeming more evident to me that it really comes down to the individual's sharpening skills. So what say you all?
 
I say it is more about the skill than the steel, but I believe some steels have better abilities to take a finer edge. I have found Aus-8, 154cm, S30V, CV (and most other carbon steel), and SAK steel take a very good edge. I have had a couple problems getting d2 scary sharp, but cpmD2 was no problem. I think that it was probably the edge geometry and skill (or lack there of) that prevented me from getting a really good edge on D2, so my jury is still out on that one.
 
I had a Benchmade 710D2 that I got in a trade from CL01. He sharpened it before I got it and it had a very polished edge. After stropping it on newspaper, I was able to split a hair in 3, shave without touching the skin, split hair without touching the skin and pushcut newspaper. CL01 has some great sharpening skills.

I just received an Emerson that I've been anxiously waiting for with 154cm (I believe) and it was able to do all of the above, so I definitely agree with you on that one.
 
I suppose all common knife steels can be given a very keen edge if the heat treat is good and you have the patience to find what media and techniques work best for that steel. But some steels are just easier to sharpen, for example it's generally going to be less trouble putting a scary sharp edge on a blade which has low carbide content and forms only very small carbide aggregates, as opposed to high carbide steels like S30V and D2.

IMO in practical terms, the bigger problem is that most common production blades you run into that are hard to sharpen, especially those that want to form bad burrs, also don't hold an edge very well either. So they're really not worth the trouble.
 
Dog of War said:
I suppose all common knife steels can be given a very keen edge if the heat treat is good and you have the patience to find what media and techniques work best for that steel. But some steels are just easier to sharpen, for example it's generally going to be less trouble putting a scary sharp edge on a blade which has low carbide content and forms only very small carbide aggregates, as opposed to high carbide steels like S30V and D2.

IMO in practical terms, the bigger problem is that most common production blades you run into that are hard to sharpen, especially those that want to form bad burrs, also don't hold an edge very well either. So they're really not worth the trouble.
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I definitely agree with this statement, which is why I worded my original post like I did. And if this is what people meant when they made comments like "it doesn't get very sharp", then that's fine. But for the sake of newer people and just to ensure that people in general know what these people mean, I think we should be more accurate in our explanations about the way these steels behave.

I sure most will agree that there's an important enough difference between "This steel doesn't get sharp" and "It may be difficult to get this particular steel to get as sharp for the following reasons...". I think most steels will get sharp enough and retain its edge long enough for the average person looking for a nice EDC.
 
I have come first circle on SAK's I convex everything I have now and after touching up my son's camper it shaved hair so easily, meaning it just seemed to part it without any effort that I now have a bald arm from getting carried away :o

I think there really are very few steels you can't get sharp if you know what you are doing.
 
It all comes down to one word...geometry. Primary grind and edge. Any steel can become "scary sharp" if the geometry is right.
Scott
 
From my perspective of scary sharp 154CM/ATS-34, D2, 440A/B/C, almost any CPM steel such as S30V, and even SAK stainless get distinctly less sharp than carbon steels, A2, 12C27, AUS4/6/8/10, VG10, BG42, and 420HC. The stainless steels that are overloaded with chrome (over 14%) or steels overloaded with alloying materials have a sharpness limit (or at least a reasonable sharpness limit) that is lower than some of the simpler high grade steels. I can force a finer edge on almost anything with an ultrafine diamond abrasive, but without that the fancy abrasion resistant steels tend to plateau at a less than scary sharp edge.
 
Gossman is right, I think. Even the crappiest $.99 Store folder with soft mystery stainless gets scary sharp if the profile is there to support it.
 
Yep. Defining "scary sharp" is part of it. I can get almost any of my knives scary sharp. How many come out of the box that way? That's another question. Most of my Cold Steel plain edge knives come that way. So did my Kershaw Storm. My Byrd Cara-Caras were pretty sharp and though none of my Smith & Wesson knives came out of the box scary sharp, they all sharpened to scary sharp and some even stayed that way.

The only knives I've had problems with are the CRKT chisel grind knives. They don't come scary sharp, neither can I make them that way. I have an M21-04 that is V-grind and though it came out of the box fairly sharp, it wasn't scary sharp. I was able to get it scary sharp, though, in less than two minutes. My Spyderco Native also didn't come out of the box scary sharp, but it sharpened up nicely, too. My Buck 110 Alaskan wasn't scary sharp out of the box, but it sharpened to razor sharp in seconds. Oh, and my Benchmade Ascent came out of the box very sharp. Very nice knife.

Again, Cold Steel seems to send their knives out ready to use and I'm always very careful when I break one out. There are so many good knives out there, so many great sharpening systems that it's difficult to end up with a really bad knife (unless you buy a Gerber or a low-end CRKT).
 
sharpness is all about geometry, especially right down at the tip. The difference between a sharp blade and a scary sharp blade might be this small:

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I'd make them bigger so it's more obvious, but it's sort of tedious. You get the idea.

sharpening a blade (if done well) brings it closer and closer to that perfect edge. Down at the micrometer, if not nanometer or picometer level is the difference between sharp and scary sharp, the ability of steel to maintain an edge so thin that a few atoms could be the final thickness is what makes a super steel. At some point all edges flatten out, the biggest difference is how wide the edge is. That is why thinner edges cut better but dull faster. The thin profile is more likely to have a thin edge, but it will wear out faster. However, as it wears it remains thinner than other blades, so it is quicker to resharpen and stays relatively sharper. Wider blades don't noticeably dull as fast because more material has to be removed from a wider grind in order to dull it noticeably.
 
For me d2 is a pain. Once it does take a decent edge it will hold it. I have a couple of knives from Bob Dozier and it still amazes me to this day how he gets his d2 so sharp.
 
The only thing I'd hazard is carbide-coated titanium... I'm not sure that'll get "scary sharp", but I'm not certain.

Talonite/Stellite is also pretty difficult to get extremely polished sharp -- it prefers to be a little ragged and/or toothy especially with its sticky burr. It's

The rest is just a matter of getting the angle and burr right, I think.

-j
 
You can get brass scary sharp. Mild steel has been sharpened and would shave. Now the point I think is holding that edge. As stated in prev posts, some steels are a real pain to bring to the true sharpened state but once there are easy to maintain. I think how easy it is to sharpen and how long it retains an edge are the important factors. JMOHO.
 
Jeff Clark said:
From my perspective of scary sharp 154CM/ATS-34, D2, 440A/B/C, almost any CPM steel such as S30V, and even SAK stainless get distinctly less sharp than carbon steels, A2, 12C27, AUS4/6/8/10, VG10, BG42, and 420HC. The stainless steels that are overloaded with chrome (over 14%) or steels overloaded with alloying materials have a sharpness limit (or at least a reasonable sharpness limit) that is lower than some of the simpler high grade steels. I can force a finer edge on almost anything with an ultrafine diamond abrasive, but without that the fancy abrasion resistant steels tend to plateau at a less than scary sharp edge.
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I agree with this.

The reason is about carbide size.
Large carbides like tool steels = difficult to sharpen (440C, D2, ATS34, 154CM).
Mid-size carbides = semi-difficult to sharpen (CPMs, ZDP and other powder metallurgic steels).
Small carbides and carbon steels = easy to sharpen (12C27, 13C26, 'some' 420 steels, A2, 1095 etc.)
 
So it looks like most of us agree, just about any common steel can get scary sharp. This was my point for this thread. I wasn't talking about edge retention at those levels or how difficult it is to get them there. This thread was specifically asking about the ability of these steels to get to that point.

I wouldn't have brought it up if it weren't for so many comments that I continue to read about steels "not being able to get very sharp". If the problem is that for daily usage, it's impractical because the steel is so difficult to work with for whatever reasons, I say people should explain those reasons rather than tell the world that the steel just doesn't get sharp.

And I still believe that some of those comments were based on the fact that some of those individuals just can't sharpen very well. This isn't a shot at Confederate, because from his explanation, he can get the rest of his knives very sharp, so I would think it is the steel in that instance (I agree with his comment on out of the box sharpness for CS knives).

I would bet that there is a vast difference in what members think of as "sharp" on these forums.
 
My perspective comes from about 50 years of sharpening knives. Sometimes I sharpen 50 knives in a day. Back 40 years ago I used to think that steel was steel and would all get equally sharp. I used to amuse my friends by sharpening tin can lids and throwing them like razor sharp miniature Frisbees. They always called me "the guy who sharpens razor blades before he uses them". Then stainless and tool steels started to become more common and I changed my mind. I could still get a shaving edge, but I started to notice that when I got it on some of these steels it was very flimsy. I finally figured out that I was getting an edge that was dependent on having a burr. I could only get that scary edge if I finished my honing using stropping style edge trailing strokes which lines the burr up with the apex of the edge. If I did a thorough job of deburring the sharpness was a step down from what I was used to with even the cheapest carbon steel. I didn't make dramatic improvements till I moved on to diamond hones.

For me the question is whether you have actually compared the edge that you can get using the same method on both 1084 carbon steel and 154CM. As part of this comparison you should be honing at less than 10 degrees per side. I don't see how anything can qualify as "scary sharp" with a geometry that is less acute than that. The other thing is have you completely deburred the edge. All these things controlled you should see a distinct difference between 1084 and 154CM. You may be happy with the edge that you get on 154CM, but I won't buy another blade that uses it. For an abrasion resistant steel I much prefer D2 to 154CM.
 
Kaizen1 said:
I gotta get a carbon blade...
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Definitely fewer surprises when it comes to sharpening. There are some stainlesses that are pretty user friendly, however: the Sandviks I've used sharpen easily just like good carbon steel, take a wonderful edge and hold it quite well, VG-10 is another. 154CM on the other hand can be a bitch, which is surprising in a way since I don't believe it contains any vanadium which forms the hardest carbides, and the AUS8 blades I've had always seemed to require a lot of fussing around to get really sharp.

Good thread, Kaizen, I think you're definitely on to something, with all the steels available today sharpening has become a lot more complicated.
 
Dog of War said:
Definitely fewer surprises when it comes to sharpening. There are some stainlesses that are pretty user friendly, however: the Sandviks I've used sharpen easily just like good carbon steel, take a wonderful edge and hold it quite well, VG-10 is another. 154CM on the other hand can be a bitch, which is surprising in a way since I don't believe it contains any vanadium which forms the hardest carbides, and the AUS8 blades I've had always seemed to require a lot of fussing around to get really sharp.

Good thread, Kaizen, I think you're definitely on to something, with all the steels available today sharpening has become a lot more complicated.
Click to expand...

I've had great experiences with my VG-10 Endura Wave. I reprofiled it and was able to split a hair in 4. If that's not at least on the low end of "scary sharp" I don't know what is. I just got a 154cm bladed Emerson, so I'll keep that in mind once I get to the point where I'll have to really sharpen it, but it came VERY sharp. Thanks DOW.
 
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