bm's s30v

orthogonal1 said:
Not neccessarily.

I've sharpened some soft steels, usually stainless, that took a bit of finesse to get a decent edge on. The steel migrates and folds over.
Click to expand...

I agree, underhardened steel is a pain to sharpen because it is very prone to forming extremely stubborn burrs. CRKT's AUS-6 comes to mind, as mine just loved to burr and it was a PITA to get a clean edge on it. I prefer steels run on the harder side as in my experience they are more crisp and less prone to excessive burring.

Mike
 
Ortho,I've found much information on Arkansas stones at: www.danswhetstones.com .
Giving government standards and specific gravity.On wikapedia googling silica,silicon dioxide, SiO2 which Arkansas stones are pure.They place the hardness at 7 Mohs. So,
your figure was close.Still, not ceramic but hard enough to sharpen S30V in the Black Hard Arkansas and Translucent hard categories.DM
 
But not harder than Vanadium carbide, either.

So, perhaps why so many, myself included, have felt that S30V is more akin to a stainless D2 because both steels take a "toothy" edge may be due to a failure of our stones to wear away the Vanadium carbide when sharpening.

Yeah, I have gotten S30V blades shaving sharp with ceramics and good old "carbideum" (however you spell it), but the edges were toothy immediattely or became so shortly after some use. Shaving sharp with a decently hard steel usually isn't all that difficult to achieve.

Diamond stones and pastes made a noticeable difference in both speed of sharpening and the performance of the edge. Instead of mere shaving sharp, I can get push-cutting-paper sharp when I want it. Diamond paste stopping can get me to "silly" sharp, push-cutting "onion skin" paper for example.
 
Roger999 said:
If it is soft then it should be easier to sharpen.
Click to expand...

I wish! Unfortunately the softer steels tend to bend and burr easily, I've had two knives with both cheapies and I had to really work to get the burr off. I think right about 60-61 HRC sharpens the best.
 
Ortho,After some extensive searching I've found that vanadium is only 6.7 Mohs www.answers.com/topic/vanadium .Then gets maybe one point harder after heat treating to 7.5-7.7 .wikidedia.org/wiki/Mohs_scale.I spoke w/Mr.Dan Kirschman of danswhetstones.com and he said that he has found some of the deep sedimentary black hard Arkansas stones to be harder than 7 Mohs. So, this is why the very best hardest
black - translucent Arkansas stones CAN sharpen S30V. As well as other steels having
vanadium carbides.As they are close to the same hardness depending on individual stones and heat treat of the vanadium steels.Hope this helps.DM
 
Last edited:
orthogonal1 said:
But not harder than Vanadium carbide, either.

So, perhaps why so many, myself included, have felt that S30V is more akin to a stainless D2 because both steels take a "toothy" edge may be due to a failure of our stones to wear away the Vanadium carbide when sharpening.

Yeah, I have gotten S30V blades shaving sharp with ceramics and good old "carbideum" (however you spell it), but the edges were toothy immediattely or became so shortly after some use. Shaving sharp with a decently hard steel usually isn't all that difficult to achieve.

Diamond stones and pastes made a noticeable difference in both speed of sharpening and the performance of the edge. Instead of mere shaving sharp, I can get push-cutting-paper sharp when I want it. Diamond paste stopping can get me to "silly" sharp, push-cutting "onion skin" paper for example.
Click to expand...

I don't have Arkansas stones, but my ceramics and AO lapping films put edges on S30V so sharp it is hard to whittle hair because the hair just pops in two. Diamonds may cut the carbides better, but my edges get extremely polished and hold them decently (it's no ZDP-189 or M4 in that department). Sure, diamonds will cut anything, but between my ceramics and my Shapton Glasstones they get any steel sharp and in the finer grits don't require the super PITA break in process that the DMT XX Fine requires. At the S30V level the Vanadium may be low enough in percentage to not be a huge factor in putting on a very sharp, polished edge that pushcuts newsprint so far from the point of hold it is hard to believe like my Manix did yesterday when I tested it's sharpness.

Mike
 
gunmike1 said:
I don't have Arkansas stones, but my ceramics and AO lapping films put edges on S30V so sharp it is hard to whittle hair because the hair just pops in two. Diamonds may cut the carbides better, but my edges get extremely polished and hold them decently (it's no ZDP-189 or M4 in that department). Sure, diamonds will cut anything, but between my ceramics and my Shapton Glasstones they get any steel sharp and in the finer grits don't require the super PITA break in process that the DMT XX Fine requires. At the S30V level the Vanadium may be low enough in percentage to not be a huge factor in putting on a very sharp, polished edge that pushcuts newsprint so far from the point of hold it is hard to believe like my Manix did yesterday when I tested it's sharpness.

Mike
Click to expand...

Agreed, if the carbides were really that much harder and that much of a problem they would be cutting into the stones leaving gouges. I've sharpened S90V on waterstones before so I really don't believe that you MUST use diamonds because they are the only thing that will work.
 
Yeah, I have gotten S30V blades shaving sharp with ceramics and good old "carbideum" (however you spell it), but the edges were toothy immediattely or became so shortly after some use
Click to expand...

That's just the characteristics of S30V as it wears down. As for being toothy right off the stone that more related to the grit of the stone.
 
David Martin said:
Ortho,After some extensive searching I've found that vanadium is only 6.7 Mohs www.answers.com/topic/vanadium .Then gets maybe one point harder after heat treating to 7.5-7.7 .wikidedia.org/wiki/Mohs_scale.I spoke w/Mr.Dan Kirschman of danswhetstones.com and he said that he has found some of the deep sedimentary black hard Arkansas stones to be harder than 7 Mohs. So, this is why the very best hardest
black - translucent Arkansas stones CAN sharpen S30V. As well as other steels having
vanadium carbides.As they are close to the same hardness depending on individual stones and heat treat of the vanadium steels.Hope this helps.DM
Click to expand...

You're looking at Vanadium and Vanadium steels, not Vanadium Carbide, the constituent element.

This site indicates that Vanadium carbide has a hardness of 2660 Knoop, which if you look at the hardness for Tantalum Carbide, should yield a Mohs hardness in the 9-10 range.

http://www.ppm.bc.ca/Cermet_Carbide_Nitride_Powder_Products.html

The issue isn't whether a sharp edge can be obtained, the issue is whether or not you are actually sharpening all of the steel or whether some constituent elements are simply being pulled out. Is it as sharp as it could be? Or are people getting a toothy edge because they are pulling out the VC?
 
Last edited:
knifenut1013 said:
That's just the characteristics of S30V as it wears down. As for being toothy right off the stone that more related to the grit of the stone.
Click to expand...


Same stones, same ceramics, same final grits - toothier edge.

Using diamond stones and lapping compounds, same edge.

I have knives in multiple steels, so I do make reasonable comparisons.
 
orthogonal1 said:
Same stones, same ceramics, same final grits - toothier edge.

Using diamond stones and lapping compounds, same edge.

I have knives in multiple steels, so I do make reasonable comparisons.
Click to expand...

For me the ceramics leave a smoother edge and the diamonds a naturaly toothier edge. I have never experienced any problems with a toothy edge from a ceramic its always been very smooth and high polished. I also have the spyderco UF ceramic and the DMT XXfine, both rated a 3 micron. They will both yield very similar sharpness levels but in no way it the DMT stone producing a finer/refined edge, its just not possiable because of the abrasive material's shape.
 
Skimo said:
I wish! Unfortunately the softer steels tend to bend and burr easily, I've had two knives with both cheapies and I had to really work to get the burr off. I think right about 60-61 HRC sharpens the best.
Click to expand...
Burrs that bend over easily are very easy to get rid of, running it down a piece of wood usually does the trick.
 
orthogonal1 said:
You're looking at Vanadium and Vanadium steels, not Vanadium Carbide, the constituent element.

This site indicates that Vanadium carbide has a hardness of 2660 Knoop, which if you look at the hardness for Tantalum Carbide, should yield a Mohs hardness in the 9-10 range.

http://www.ppm.bc.ca/Cermet_Carbide_Nitride_Powder_Products.html

The issue isn't whether a sharp edge can be obtained, the issue is whether or not you are actually sharpening all of the steel or whether some constituent elements are simply being pulled out. Is it as sharp as it could be? Or are people getting a toothy edge because they are pulling out the VC?
Click to expand...
Ortho,There are some obvoius problems w/your site.Looking at Tantalum as you say at 9-10 at 2000 Knoop.Then VC at 2660 Knoop that would put it over 10 Mohs and diamond would not even cut it!!I've also seen Tungsten on other sites listed at 7.5 Mohs and stated it was very similar to VC.Then couple this w/ personal experience of several writing in saying; they are sharpening S30V well on AO stones (9.2 Mohs) and arkansas stones (7.5 Mohs).This would bear more looking into.DM
 
David Martin said:
Ortho,There are some obvoius problems w/your site.Looking at Tantalum as you say at 9-10 at 2000 Knoop.Then VC at 2660 Knoop that would put it over 10 Mohs and diamond would not even cut it!!I've also seen Tungsten on other sites listed at 7.5 Mohs and stated it was very similar to VC.Then couple this w/ personal experience of several writing in saying; they are sharpening S30V well on AO stones (9.2 Mohs) and arkansas stones (7.5 Mohs).This would bear more looking into.DM
Click to expand...


The problem is that you're having an issue with what the scales represent.

http://www.themeter.net/durezza_e.htm

Mohs is a comparison, X mineral is harder than Y material.

Knoop is a test, how much something is indented by a standard indenter.

This is a prime example of why an understanding of what a scalar is being used and what it means is important.
 
orthogonal1 said:
The issue isn't whether a sharp edge can be obtained, the issue is whether or not you are actually sharpening all of the steel or whether some constituent elements are simply being pulled out. Is it as sharp as it could be? Or are people getting a toothy edge because they are pulling out the VC?
Click to expand...

I don't think so. I have very good results finishing up with ultra fine ceramics on my S30V and S90V knives. Takes a very keen hair splitting edge and holds it.
 
If the VC are so much harder how do you explain this.

Finished with UF ceramic
Picture595.jpg


Picture594.jpg


Picture593.jpg
 
I explain that as being a highly polished edge.

But, as stated previously, I already acknowledged that one can get S30V sharp.

Here is a hypothisis: When the grit gets finer, the metal surrounding the Vanadium carbides is not sufficiently removed to allow the noted carbides to be ripped out, e.g. it is like trying to pry a stone out of concrete without getting sufficiently under the stone to move the stone out. As a result, the sharpener is riding on the Vanadium carbides.

Such a theory accounts for the relatively toothy edge behavior one sees when comparing, say S30V to M2, sharpened to the same grit.

I'd like to see some magnified pictures in the 400x plus range.
 
Last edited:
The edge has sence been polished with 1 and 0.5 micron compound so I don't know how much good a pic at 400x would be.
 
You must log in or register to reply here.
Back
Top