Worlds sharpest blade???

jasonbroni said:
Too sharp equalls rolling.. (I know next to nothing next to 95% of the people here, but that's my 2 cents...)
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Though I appreciate your honesty regarding your knowledge base, I must disagree.

Different alloys can hold stability at the apex at differing degrees of inclusiveness. If you were to take 420j2@58hrc to 15 dps without a microbevel or a heavy convex, you would roll an edge much faster than zdp-189@64hrc at 15 dps from rockstead while chopping parsley.

The part that often raises the hardest question is which alloy will work best for "X" while still being good for "Y"?

If you want a good kitchen slicer, don't look for S7. Even though S7 is super high toughness, it still would be outperformed as a kitchen chopper due to the fine nature of the chopping and (usually) softer media being chopped.

I find VG10, 52100, AEB-L, 1084, 1005 and O1 to work nicely in the kitchen.

VanDammet, It would behoove oneself to seek out "bodog" and "bluntcut" in the testing threads.

If nothing else it would be a good progression in your search.
http://www.bladeforums.com/forums/s...e-steels-multiple-hardnesses-multiple-testers

I personally look into high hardness M2, 52100, and AEB-L.
Good Luck
 
This is a bit of a ridiculous question.

The sharpest knife I have is the one I make the sharpest through sharpening :thumbup:
 
Unlike measurements such as length, thickness, and mass, there is no way to quantify sharpness and use it to compare models. The best you could do is define sharpness as the thinness of an edge and use that as a gauge. But that really only indicates how fine you can make the material on a boundary. Other properties like material hardness and the like will determine if it can actually separate(cut) the structure of other materials without falling apart-- and what are the other materials being cut into? And then there are issues of imperfections in the blade that might influence the properties of the edge. Sharpness is a qualitative property and you can't assign a universal score to it and create a rank.
 
Examples of ambiguity in trying to define sharpness as an absolute property:

A butter knife is a very sharp blade when cutting into butter. It creates clean and effortless cuts into the material.

Obsidian makes a very fine cut into flesh and creates less lateral tissue damage than steel. The AMA tried to get approval to use it in place of steel in scalpels.

But A butter knife won't cut into flesh efficiently without generating large amounts of pressure. Obsidian is extremely brittle and will shatter on heavy duty materials that steel will make quick work of. It also will drag in a material like butter. Does this mean that steel is sharper than a butter knife and Obsidian? No. It means that you need to pick the right tool for the materials being used. Neither is duller or sharper. It makes no sense to speak of sharpness in absolute terms.
 
Bubba, while there may not be a standard, there is one method that was proposed on this forum not too long ago.
http://www.bladeforums.com/forums/showthread.php/1285538-Edge-Sharpness-Tester?highlight=Bess

This BESS tester may directly address your point. But I do agree that, for the most part, an edge is just sharp or dull relative to another.
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To address your second post, you can say whether one is absolutely sharper than another. Just because one type of material used to do the cutting outperforms another, doesn't mean it is "sharper" just more "efficient" at cutting one particular material.
 
NJBillK said:
Bubba, while there may not be a standard, there is one method that was proposed on this forum not too long ago.
http://www.bladeforums.com/forums/showthread.php/1285538-Edge-Sharpness-Tester?highlight=Bess

This BESS tester may directly address your point. But I do agree that, for the most part, an edge is just sharp or dull relative to another.
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To address your second post, you can say whether one is absolutely sharper than another. Just because one type of material used to do the cutting outperforms another, doesn't mean it is "sharper" just more "efficient" at cutting one particular material.
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Agreed.. I think sharpness really needs to be discussed in terms of intended use. e.g. Obsidian is sharper than steel when cutting something with the texture of skin or flesh. When cutting wood, I want the steel.

Which I think moves the discussion into another area--cutting. A cut is really nothing more than the splitting of material. Sharpness is the ability to produce a cut into a material. Almost any tool will cut with enough force applied. But a sharp tool will produce a much finer cut and the splitting will be done in a manner that does not interrupt the granular structure of neighboring material, which will create sheering forces and tears and splits.
 
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While I can see what you mean, I disagree.

Whether something can cut something else but maintain a usable "edge", it doesn't necessarily mean that it is "sharper" prior to the cut.

If I have a lightly used (and slightly rolled) chisel and a knife of 420j that has been sharpened, the latter would (initially) be considered "sharper". Once they are both pounder through a car door, the chisel would pull ahead.

But, this is where I see a flaw in your logic. Once the knife is rounded to the point that the it cuts less efficiently than the chisel, the chisel is now sharper, regardless of how sharp they started, and what they can maintain a working edge through.
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In the spirit of the OPs post, he was asking what can be the sharpest, not which can maintain a working edge the longest, which is what you are describing.
 
NJBillK said:
While I can see what you mean, I disagree.

Whether something can cut something else but maintain a usable "edge", it doesn't necessarily mean that it is "sharper" prior to the cut.

If I have a lightly used (and slightly rolled) chisel and a knife of 420j that has been sharpened, the latter would (initially) be considered "sharper". Once they are both pounder through a car door, the chisel would pull ahead.

But, this is where I see a flaw in your logic. Once the knife is rounded to the point that the it cuts less efficiently than the chisel, the chisel is now sharper, regardless of how sharp they started, and what they can maintain a working edge through.
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In the spirit of the OPs post, he was asking what can be the sharpest, not which can maintain a working edge the longest, which is what you are describing.
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There are just too many variables to assign an absolute sharpness score and say this material can be made sharper than that. Again, it will all depend on what one will be cutting into to test the sharpness. Creating a universal value for sharpness is not really possible. How sharp a blade can be made also cannot be assigned an absolute universal value for the same reason. Sharpness is a qualitative property of a blade. You can measure the thickness of an edge but that says nothing about how it will cut into various materials. There is edge geometry, angle, imperfections in the steel, strength of material, and so on etc..This will vary from sample to sample. One piece of CPMS30V steel may have microscopic properties that differ from another sample of the same steel and result in a different score. It is impossible to score a blade because it is impossible to score a material. One could only score specific examples individually. It makes no sense to say which blade can be made the sharpest.

If it was possible, it would have been done long ago and manufactuers would be touting the sharpness rating of their steels and it would be on the packaging in the specs data. The engineers know that sharpness is not quantifiable on a universal level.

So, to answer the question, which blade material can be made the sharpest? It is an ambiguous question with no clear definable answer. We are just left with observations gleaned through testing and use that some steels and materials hold an edge longer than others under heavy use and retain a degree of cutting sharpness longer. Some steels can hold a thinner edge under heavy cutting. But that's about it. You cant quantify it. Too many factors.
 
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And this is why I am glad that my surgeon opted to use D2, over a finer grained alloy. I didn't want the blade to wear as fast during surgery, regardless of how sharp it could initially be.

/sarcasm off

The reason why the manufacturer won't state how sharp their knives are, to a measured degree is that it would be too costly to sharpen each knife to such a point that it would be worth them to tote it as such. On top of that, as soon as someone cut something, it would degrade the sharpness (thus potentially making a different knife "sharper").


If the difference in one alloy is as simple as one wears at a slower rate, and that is the only thing that can be empirically judged, then why have alloys AEB-L, and 12c27 been invented?

There is a direct market for high volume carbide alloys with higher wear rates vs more pure alloys and lower wear rates but a capability to take a more refined edge.

This is primarily due to where the emphasis is placed, with a higher carbide volume and size such as D2, you can only go to a certain thinness prior to experiencing carbide tear out, and due to the size, you can only polish an edge to a certain degree.

A more pure alloy (AEB-L, Hitachi white, super blue instance) can be taken to a measurably keener edge. Primarily due to the lower carbide size/volume, and the "cleanliness" of the alloy.

The OP was asking which steel can be the sharpest. Not which steel can maintain a working edge the longest.
Not which steel will be the sharpest after cutting up 400 linear feet of double walled cardboard?

So while I do believe that you are answering a related question, you are not answering what the OP was originally asking. While a rather small distinction, it is subtle yet notable difference.
 
Boy this thread got deep fast. 30 posts in and no pics with this kind of title...[emoji13]
 
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