What happens if you keep using the wrong sharpening stone?

hank_rearden

hank_rearden

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Jun 7, 2002
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what if you keep sharpening your high-vanadium blade using minerals that are softer, silica from natural stones, or soft ceramic? will you keep producing a toothy edge and dull polish? assume you still have a workable progression in grit size.
 
This is a highly technical explanation of what happens when the alloy is harder than the abrasive.

[video=youtube;sdxf32F3j3k]https://www.youtube.com/watch?v=sdxf32F3j3k&index=30&list=PLFA60459F187488EF[/video]
 
Jason B. said:
This is a highly technical explanation of what happens when the alloy is harder than the abrasive.

[video=youtube;sdxf32F3j3k]https://www.youtube.com/watch?v=sdxf32F3j3k&index=30&list=PLFA60459F187488EF[/video]
Click to expand...

Excellent video Jason. Definitely illustrates the point well.
 
Jason B. said:
This is a highly technical explanation of what happens when the alloy is harder than the abrasive.

[video=youtube;sdxf32F3j3k]https://www.youtube.com/watch?v=sdxf32F3j3k&index=30&list=PLFA60459F187488EF[/video]
Click to expand...

In English:
If you're using non powdered steel with high amounts of vanadium/molybdenum/tungsten (example, D2) the blade will wear the hell out of a softer sharpening media and leave a toothy edge.
If you're using powdered steel with high amounts of vanadium/molybdenum/tungsten (example, CPM-D2) the blade will still wear out the softer sharpening media, but much slower and will produce a better/finer edge.
 
Well, all of it. It's about the interaction of abrasive and hard alloy elements and how they react when contacting each other. It has nothing to do with how coarse or fine of a edge will result or how the stone will wear. In English, it's talking about vanadium carbides and how aluminum oxide is the wrong tool for the job.
 
You're right, the video isn't about edges at all. I was reflecting on how that video was relevant to op's question.

Reflecting on the example with the ship and the icebergs:
The ship is your sharpening media while the icebergs are your edge. The ship will wear faster from large icebergs, and the icebergs will keep their large structure. Ie, that's the same as using D2 on a soft sharpening media, which would surely leave you with a toothy edge.

I don't see where I'm wrong.
 
Sounds good in theory but doesn't happen like that in practice. D2 contains chromim carbides which are much softer and easily cut by most all sharpening media, Vanadium carbides are the troublesome carbides because they are much harder than aluminum oxide. Because the alloy is harder than the stone abrasive you get a burnishing action and instead of cutting the steel you get a polishing action even at coarse grits.

Stones clog and have minimal effect when this happens, they don't just keep working like they do on every other steel.
 
D2 is maybe not the best example, as the Chromium carbides can be shaped by ALumOx tho SiC or diamond do seem to work better. But as an example, D2 tends to have large carbides that anchor the surrounding steel. When the abrasive in question cannot clear those carbides in pieces, the edge tends not to progress beyond a given point, and the carbides themselves while being harder than the abrasives will wear on the abrasives and not shape aggressively. You end up with an edge that is not toothy nor ground thin - an OK edge that could be a lot better.
 
So if I'm understanding this correctly, it would leave chromium carbide imbedded into the softer sharpening media while leaving vanadium carbide behind? So you'd essentially be sharpening you edge on a thin layer of chromium carbide resulting in a polishing action of the vanadium carbide? Essentially, this would lead nowhere in terms of sharpness...
 
No. The carbides don't fall out they get left in the steel.

The chromium carbides are what you will find in D2 and don't pose a problem. Vanadium carbides like found in S30V are the trouble.

I feel like we are talking in circles though so maybe re watching the video would clear it up instead of us repeating everything the video explains.
 
Ya know, I just referred to a steel composition chart and didn't realize that D2 has relatively low amounts of vanadium carbide. Not that that matters much, but I understand why that was a bad example I reflected on now.

Thanks for the input Jason B.
 
HeavyHanded said:
D2 is maybe not the best example, as the Chromium carbides can be shaped by ALumOx tho SiC or diamond do seem to work better. But as an example, D2 tends to have large carbides that anchor the surrounding steel. When the abrasive in question cannot clear those carbides in pieces, the edge tends not to progress beyond a given point, and the carbides themselves while being harder than the abrasives will wear on the abrasives and not shape aggressively. You end up with an edge that is not toothy nor ground thin - an OK edge that could be a lot better.
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I think that bolded portion above most aptly describes my impressions of the scenario when carbides get in the way of the abrasive being utilized. Almost verbatim, it describes my lasting impression of S30V (and it's vanadium carbides) when attempting to refine it on SiC wet/dry sandpaper. At coarser grits to around ~600 or so, it grinds OK. But in attempting to take it further through 800/1000/2000/etc, progress virtually stops. I always ended up with what seemed to be a 'burnished' edge & bevels, which wouldn't polish any further beyond a 'hazy mirror' and always left the edge too thick to be an effective cutter. When switching to diamond abrasives at similar and finer grits, the difference in working speed and refinement becomes glaringly obvious, as diamond still blazes straight through the vanadium carbides, as if they were butter. At 3µ and lower, diamond is very impressive on S30V especially, when stropping it on balsa or other wood (I like basswood for this); the mirror polish comes up FAST at that 3µ threshold.

The non-powder-metal version of D2 is unique, in that aluminum oxide or SiC can still cut it, but it's still much slower because the chromium carbides are so very BIG (can get up to ~50 microns, or even bigger at times). So, even though AlOx or SiC can still work with it, I still prefer to do heavy grinding with diamond on non-CPM (ingot) D2. Once the good geometry is set, D2 is easily refined on AlOx or SiC, and in fact, I positively LOVE what can be done with AlOx stropping on D2.


David
 
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sorry if this doesnt fit, but wuld this description be good for the sv3 and d2 steels?
Specifications: Size:150mm*20mm*5mm Type: 001:Corundum oil stone(200#) 002:Green carbon oil stone(400#) 003:Boron carbide oil stone(800#) 004:Black onyx oil stone(1500#) 005:Ruby oil stone(3000#) 006:White agate oil stone(6000#) 007:Diamond oil stone(8000#) 008:Emerald oil stone(10000#) Package Included: 8pcs Sharpening Stones.. jeff
 
rc4u12 said:
sorry if this doesnt fit, but wuld this description be good for the sv3 and d2 steels?
Specifications: Size:150mm*20mm*5mm Type: 001:Corundum oil stone(200#) 002:Green carbon oil stone(400#) 003:Boron carbide oil stone(800#) 004:Black onyx oil stone(1500#) 005:Ruby oil stone(3000#) 006:White agate oil stone(6000#) 007:Diamond oil stone(8000#) 008:Emerald oil stone(10000#) Package Included: 8pcs Sharpening Stones.. jeff
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Basing these assumptions only on the descriptions given, not knowing anything else about the specifics of each:

'Corundum' should be aluminum oxide stone. Might be OK with D2, but slower or ineffective on S30V (S3V?), depending on quality.
'Green carbon oil stone' is ??? Might be a reference to a silicon carbide stone (sometimes SiC is 'green'); if it is, should be OK with D2, not so sure with S30V/S3V.
'Boron carbide' might be OK with both steels (again, depending on quality).
Assuming the 'Black onyx' and 'White agate' are natural stones; not likely very effective for either steel, if so (not hard enough for the carbides in either steel).
The 'Ruby oil stone' and 'Emerald oil stone' might also be aluminum oxide; could be OK with D2, questionable with S30V (S3V?).
Assuming you meant to type 'diamond' for 'iamond oil stone'? If so, diamond should work for anything.

With all the above, the naming of the stones mentioned is vague/suspicious to me, which raises a red flag about quality (what brand are these?). I'd probably look for other well reputed brands/types, like Norton Crystolon/India for D2 at least, and maybe for S3V in coarser grinding. Look for brands like DMT, Eze-Lap or Smith's for diamond hones.


David
 
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i guess i should have just posted the link..its on amazon , http://www.amazon.com/gp/product/B00M1XZ752/ref=ox_sc_sfl_title_4?ie=UTF8&psc=1&smid=A29N4ZINKM6WKD . the price is not bad but have to actually use them to find out if there any good..i did get a a #8 10000 stone sent to me for sample.i asked for a sample but should have sepcified which grit i wanted and this is what they sent me...i have not backed it yet so i havent used it.. i did get the moldmaster stones 120-600 and the diecast 900 and on the 3v steel dont seem to work well like on my kitchen knives...jeff
 
rc4u12 said:
i guess i should have just posted the link..its on amazon , http://www.amazon.com/gp/product/B00M1XZ752/ref=ox_sc_sfl_title_4?ie=UTF8&psc=1&smid=A29N4ZINKM6WKD . the price is not bad but have to actually use them to find out if there any good..i did get a a #8 10000 stone sent to me for sample.i asked for a sample but should have sepcified which grit i wanted and this is what they sent me...i have not backed it yet so i havent used it.. i did get the moldmaster stones 120-600 and the diecast 900 and on the 3v steel dont seem to work well like on my kitchen knives...jeff
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Even looking at those on Amazon, I'm still kind of skeptical. I don't have any idea what that 'Green carbon oil stone' is; it doesn't look like silicon carbide at all, as I'd previously speculated. If I were you, I'd still shop around a bit more.

If these were being used for more typical steels, like your kitchen knives and such, they might be OK. But for higher-wear steels like D2 and 3V, the type and quality of the hones becomes more important, if they're to work very well at all. Smaller hones have to be very, very good to work on such steels, as the limited surface area places a premium on the stone's ability to cut aggressively without wearing or clogging. If they wear too fast, or aren't hard/aggressive enough, they'll usually either dish out, or glaze over and stop working altogether.


David
 
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