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Hardness and abrasion capability
- Thread starter miso2
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To Wowbagger,
Right. I understand that it is the basis of us using leather and linen for stropping. If they do not have hard minerals at all, it might take a very long time to have any effect on steels.
To DeadboxHero,
I am not trying to ditch or ignore real-world evidence. I am just trying to understand them intelligibly. I guess I am a researcher not only as my occupation but also in heart. So, please forgive my techno-centered mind
You mentioned that an alumina-based stone can polish high carbide volume steels. Why? Was the carbide tungsten carbide, which is softer than alumina? Or was it really the technique to apply pressure to the edge properly and consistently to facilitate the abrasion? Or, was it because the stone actually contains other abrasives such as silicone carbide, like some of Shapton stones? I am not asking an answer, but this is my usual attitude toward a problem......
Miso
I'm not here to call anyone out brother, I respect you guys and I learn a lot reading here too.
I'm on the same page with you, I want to understand things in depth as well.
But it seems its more complex then it appears.
I dulled the edge
o Yikes, I know) and freehand sharpened CPM S110v on all alumina.I started with the Norton India combo field stone that I use for axes, so I use it in hand with oil. Cut like a champ, then I switched to the fine orange side 400 grit ANSI which is everyone's favorite, cuts fast and isn't too aggressive that I can't deburr on the stone.
Made a respectable edge with all those expensive carbides exposed, lots of bite, and could even shave hair.
Skipped the medium grit and made a big jump to the Naniwa Chosera 3k waterstone which brought out a bright finish but not a true mirror. This stone felt glassy with the S110v but the Chosera aren't know to have the best feedback, yet it was still noticeable, also there was a definite lack of swarf on the stone compared to other steels with less carbide volume.
It only took several moments to finish on the 3k with moderate pressure ( not enough to turn any part of my nail beds white but a slight pressure on the stone and blade)
all that and I still was able to enhance the edge to a nice hair popping apex. I made a burr every step but is unbelievably difficult to detect at 3k and beyond but its still there if ya try to cut something so ya still have to go through the deburring motions
Next I switched to the Naniwa 8k Snow white, Again I noticed a very glassy feedback and very minimal swarf but I was able to hold my angle and maintain my crisp apex and polish it.
last was the Naniwa Super Stone 12K, this is a much softer, resin bond stone versus the magnesia based Chosera/professional stones that are harder and also have more alumina ceramic abrasive volume.
made almost no swarf..
haha yikes
but still polished, you can still see the Norton India scratches since I skiped the medium grit and went straight to polishing, but in the right light its a bright mirror like finish, but of course a true mirror has no scratches IMHO
Deburred on the stone and the edge felt sharp, nice bite
stropped on Chrome Oxide which is also a softer abrasive to see If I could enhance the edge further I used a light touch since the pasted strops are rather gummy and I feel like its much easier to round the apex then if using a spray or emulsion.
Still a crisp apex, can treetop hair with softer abrasives on steel with 9% vandium and 3% niobium
Grit Progression:
Norton India oilstone 240 coarse
Norton India oilstone 400
Naniwa 3k chosera
Naniwa 8k "snow white"
Naniwa 12k superstone
Chomium oxide pasted strop
deburr at each stage full deburr on strop.
***NEW GUYS- this is not the ultimate set up, Just an example for abrasive hardness vs High carbide, this is not my first choice to sharpen that stuff, just showing it can be done.
In conclusion, The ceramic waterstones would not be my first chose and in reality this in not an effective pocket knife edge finish for real world use, since I am not cutting sushi or shaving my face with the folder, I mostly just cut stuff that I throw away with my folders so I don't need the worlds cleanest cut traded for reduced edge life that the high polish gives.
Also, its not taking advantage of all those carbides S110v has to offer by concealing and shaping them in the apex rather then exposing them with deep scratches and sharp facets that will help me cut stuff more aggressively and longer before sharpening, That's the wear resistance we pay for, its just that deburring is a crucial skill and some use polishing stones as a crutch to reduce and remove burr. When they should prolly just deburr and polish the teeth with a diamond/cbn strop.
I am not advocating alumina ceramic for high carbide, just showing that its overblown about its ineffectiveness, most dudes just overpolish or round the edge when working up the apex on the stones or don't fully deburr as the final step.
Yet, just because it can be done, doesn't mean its the right tool for the job.
The ceramic alumina stones are simply not as nice as diamond waterstones for high volume carbide
This is that "grey area" I brought up, its almost impossible to talk about things without being "black and white" on a forum discussion.
Lets cover why the diamond waterstones work better.
The Naniwa Diamond 3K waterstone did not lose feedback on S110V (no pic, s35vn in photo) and would create more swarf/loadup then the 3K Chosera which means they are more efficient and actually cutting versus the alumina ceramic based Chosera.
but in the end, its the execution not the tools and at a blistering $150 to $190 per diamond waterstone, it's just not cost effective for regular dudes with families and other things to get done in life.
'cept us nerds
Also, the hard resin bond load and is slow cutting, if all you sharpen is low carbide volume steels, these resin bond diamond waterstones are slower and more inefficient at cutting regular steel since they don't release grit and swarf loads up on the resin clogging the abrasive and they also have less tactile feedback then a regular stone as well.
The only advantage if used on normal steel is that they are very, very low dishing (might take years to dish) and a brighter finish then the choseras like the superstones but without the gummy feel and fast dishing. The Naniwa diamond waterstones may even cut faster then the superstones.
The real beast for a superabrasive sharpening stone is vitrified bond since it does not clog and load, cuts faster then the choseras and more aggressively, needs a short soak and also has very, very low dishing and great feedback like a traditional high end soaking stone.
What's not to love, this has it all
...... the cost is very, very high.
"how much we talking, I might buy that"
The most affordable would be $400
for a 800 grit stone sold by JKIYikes, I can see the merit to this stone but I would have a hard time telling someone that its worth $400 unless they are hopelessly obsessed and need help
While not the badass Vitrified diamond waterstone,
I found Venev Diamond resin bond waterstones are very affordable at $81 dollars for a 8x3 inch 400/800 FEPA-F (Bout 700/2000 grit in Naniwa stones) combo stone that I ordered online through email from Gritomatic, a Russian based company run by two very passionate knife guys
I have no idea how good this is, its not going to cut as fast as a vitrified bond and I do know it doesn't come flat and that SiC powder is recommended to flatten them by Gritomatic before use since it would just kill a 90 dollar atoma plate to flatten (again abrasive hardness is only one component in the broad spectrum of wear)
hope that's all clear as mud
The moral of the story is,
If you're a new dude, you don't need this stuff, it's not going to improve your skill. Practice, Practice, Practice
If you're really into sharpening as a hobby or as a professional, the diamond waterstones may have merit to justify the increased cost since they have more longevity then normal stones and their metal plated cousins, also diamond waterstones leave a better finish without the deep scratches that reduce the precision and beauty of fully polished edges yet share the efficiency of the harder better cutting abrasives . In the end, an experienced sharpener might not like the diamond stones anyways just based on preference which is fine, if their edges are sharp who cares hahaha
Last edited:
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Wow. Thanks for the nice write up and images and for taking time to demonstrate this.
I hope you dont mind my asking a couple of questions.
The first one is whether you feel that the refinement you get with those alumina stones is similar to what you would get with diamond or CBN stones at the same grits, or alternatively whether carbides are really polished by the alumina ceramic stones (above 3,000).
The second is how much time you spent on each stone. I understand that polishing vanadium carbides with alumina is possible but may be very slow. If it can be done efficiently, then the hardness difference between them may not be as significant as I thought it is, or some alumina could actually be harder than vanadium carbide from certain angles to the crystal structures (or vice versa), due to potential hardness anisotropy bucketstove brought up.
Miso
I hope you dont mind my asking a couple of questions.
The first one is whether you feel that the refinement you get with those alumina stones is similar to what you would get with diamond or CBN stones at the same grits, or alternatively whether carbides are really polished by the alumina ceramic stones (above 3,000).
The second is how much time you spent on each stone. I understand that polishing vanadium carbides with alumina is possible but may be very slow. If it can be done efficiently, then the hardness difference between them may not be as significant as I thought it is, or some alumina could actually be harder than vanadium carbide from certain angles to the crystal structures (or vice versa), due to potential hardness anisotropy bucketstove brought up.
Miso
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Thanks,
How do I feel about the edge? its sharp, I guess they can always be sharper though
Do I think I can make a better edge with the diamond? I feel it takes less focus and time maybe but tough to say without better controlled testing since I get all my data anecdotally.
Sometimes I feel like I get a crisper edge with the diamond, but sometimes I round the apex on the diamond and have to go back and fix it, is it crisper because of proper execution? or the higher finish the resin bond diamond leaves? I don't know, I've only been using these stones for 3 months now, need more time, also SEM pictures of edges would be sweet.
Do I think the softer alumina is polishing the carbide? I don't know, I know its making the edge shiny and it cuts better but I don't have enough physics, tribology and material science learning to fully answer that now, nor the imaging to show what is happening microscopically, so I can't answer that now and that's some thick reading and it takes a lot of reading and time to understand it enough to even follow what they are talking about as it relates to knife sharpening let alone explaining it in lay terms to others while still preserving the essence of what it means.
how much time did it take?
Not as long as you would think, Ill make a video when I get time, Maybe when my S110v edge dulls from use so I don't waste the expensive steel hahaha
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Hi,
I think I said it not implied it
Oh yeah, I forgot include this part in the table because that converter doesn't allow converting from Vickers to HK because like the quoted part says,
not everything is DIRECTLY comparable,
the microhardness tests depend on time and depth not just force and area,
But the point of the data is to show that the corners are harder, even if only for 5 seconds or one pass or whatever, they will
I've updated the table with this info
[tr]
[td]Quartz corners[/td]
[td] ???1041HK/1086.5HK?? HKor 1181 HV / 1260 HV or 11.58 GPA / 12.21GPa or ~71HRC/~72HRC [/td]
[td]Silicone dioxide, Arkansas stone, anisotropy, the HK numbers iffy, not directly convertible from HV/GPa
[/td]
[/tr]
There are also microhardness numbers for alumina but nothing I could understand as easy as the SiC numbers
Some more interesting stuff with pictures
1442439-Sharpening-high-hardness-and-wear-resistant-steels
Edge effect on abrasive wear mechanisms and wear resistance in WC-6wt.%Co hardmetals
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The testing I did with 10v led me to the conclusion one can sharpen with any material, but if you compare side by side the differences will begin to show and diamond is notably better. They will be more pronounced at higher polish. At lower levels it is not important but possibly Silicon carbide is the best choice due to high friability combined with high Moh's value.
http://www.bladeforums.com/forums/s...nt-steels/page15?highlight=wear+resistant#285
#289 shows the final results. Earlier in the thread I describe the test protocol, does a solid job of isolating the test from user bias.
http://www.bladeforums.com/forums/s...nt-steels/page15?highlight=wear+resistant#285
#289 shows the final results. Earlier in the thread I describe the test protocol, does a solid job of isolating the test from user bias.
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All linens and leathers will have silica oxides in them from natural uptake and in the case of tanned leather silica is used in the process. In the case of papers you will have these oxides and titanium oxides for whitening as well as other various whitening and body building agents.
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A last thought re Vanadium Carbides. From what I have read they are manufactured in a range of harness based on forming temp, pressure, and available carbon. At the low end about = to or a little harder than AlumOx, at the high end well above.
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Taken together, I guess abrasives as hard as or harder than alumina can probably fracture vanadium carbide (at different efficiencies), presumably due to carbide crystal hardness variability and anisotropy, also depending on the carbide particle size.
(This is also based on the assumption that carbides in a steel can be fractured without pullout, which is mentioned as one of the main wear mechanisms in the paper bucketstove provided, where a tungsten carbide alloy is abraded by silicon carbide abrasives. I do not know if this can be generalized to knife steels.)
This seems to be consistent with the empirical evidence sharpening experts provided above. Considering the rate of abrasion, harder silicon carbide stones would be the first choice over softer alumina (or zilconia) stones for high vanadium carbide steels, like S35VN and above. Diamond stones would be more efficient and preferable for these steels, if the cost can be justified.
Regarding bare stropping, as HeavyHanded mentioned, they contain silicates, which is equivalent to quartz. Therefore, we cannot expect much abrasion of high carbide volume steels on leather or linen, although other stropping benefits, including what Wowbagger described above, would still be present.
Summary-updated:
(1) Natural stones like Arkansas (quartz, silicate, or novaculite) may not be the first choice when sharpening high carbide volume steels.
(2) You can use any good ceramic stones for a coarse finish above 10 micron or #1,000 ANSI grit.
(3) You would need abrasives harder than carbides for finer finishes, if you want to save time and effort. For vanadium carbide steels, this would be silicon carbide, cubic boron nitride, or diamond. Alumina can still work but not efficiently. This may also apply to strops.
Miso
(This is also based on the assumption that carbides in a steel can be fractured without pullout, which is mentioned as one of the main wear mechanisms in the paper bucketstove provided, where a tungsten carbide alloy is abraded by silicon carbide abrasives. I do not know if this can be generalized to knife steels.)
This seems to be consistent with the empirical evidence sharpening experts provided above. Considering the rate of abrasion, harder silicon carbide stones would be the first choice over softer alumina (or zilconia) stones for high vanadium carbide steels, like S35VN and above. Diamond stones would be more efficient and preferable for these steels, if the cost can be justified.
Regarding bare stropping, as HeavyHanded mentioned, they contain silicates, which is equivalent to quartz. Therefore, we cannot expect much abrasion of high carbide volume steels on leather or linen, although other stropping benefits, including what Wowbagger described above, would still be present.
Summary-updated:
(1) Natural stones like Arkansas (quartz, silicate, or novaculite) may not be the first choice when sharpening high carbide volume steels.
(2) You can use any good ceramic stones for a coarse finish above 10 micron or #1,000 ANSI grit.
(3) You would need abrasives harder than carbides for finer finishes, if you want to save time and effort. For vanadium carbide steels, this would be silicon carbide, cubic boron nitride, or diamond. Alumina can still work but not efficiently. This may also apply to strops.
Miso
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Thanks,
How do I feel about the edge? its sharp, I guess they can always be sharper though
Do I think I can make a better edge with the diamond? I feel it takes less focus and time maybe but tough to say without better controlled testing since I get all my data anecdotally.
Sometimes I feel like I get a crisper edge with the diamond, but sometimes I round the apex on the diamond and have to go back and fix it, is it crisper because of proper execution? or the higher finish the resin bond diamond leaves? I don't know, I've only been using these stones for 3 months now, need more time, also SEM pictures of edges would be sweet.
Do I think the softer alumina is polishing the carbide? I don't know, I know its making the edge shiny and it cuts better but I don't have enough physics, tribology and material science learning to fully answer that now, nor the imaging to show what is happening microscopically, so I can't answer that now and that's some thick reading and it takes a lot of reading and time to understand it enough to even follow what they are talking about as it relates to knife sharpening let alone explaining it in lay terms to others while still preserving the essence of what it means.
how much time did it take?
Not as long as you would think, Ill make a video when I get time, Maybe when my S110v edge dulls from use so I don't waste the expensive steel hahaha
I would love to see the vid!
Miso
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Personally I like to just stick to steels with low or no vanadium carbides and suddenly I don't have to be fussy about what stones I use anymore.
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Personally I like to just stick to steels with low or no vanadium carbides and suddenly I don't have to be fussy about what stones I use anymore.
:thumbup:
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In my experience I wouldn't even go high finish with silicon carbide. If you take a high VC steel and do any work on the primary with a variety of abrasives you'll quickly get an education in what the relative grind rates are, and at what point non-diamond abrasives begin to peter out. For the much smaller surface area and much higher spot pressure of a cutting bevel there is more leeway but the principles remain.
If you don't often have cause to need diamond plates you can just keep a sheet of 16 and 3 micron diamond lapping film to bridge from medium finish to a much higher uniform polish. Use with a drop of mineral oil and they last many sharpenings.
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Personally I like to just stick to steels with low or no vanadium carbides and suddenly I don't have to be fussy about what stones I use anymore.
That is an excellent point. I totally agree. I bought bunch of high vanadium steel knives and then realized that wear-resistance is not really the first thing for me......
Also, thinking now about my past failure to master free-hand sharpening, the biggest mistake probably was to pick up a S30V blade as a practice knife with alumina stones. I should have just use a plain carbon steel knife like Opinel. But I didn't know anything about steels and abrasives back then. So here is this thread.
Miso
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HeavyHanded,
OK. I will update the summary again to reflect your comment. I think using diamond films is a great idea. They are more cost effective and free from the flatness issue.
Summary-updated:
(1) Natural stones like Arkansas (quartz, silicate, or novaculite) may not be the first choice when sharpening high carbide volume steels.
(2) You can use any good ceramic stones (alumina and above) for a coarse finish above 10 micron or below #1,000 ANSI grit.
(3) You would need abrasives harder than carbides for finer finishes, if you want to save time and effort. For vanadium carbide steels, this would be cubic boron nitride or diamond. Alumina and silicon carbide can still work but not efficiently. This may also apply to strops.
(4) Alternatively, one can use diamond lapping films instead of stones for finer finishes.
Miso
OK. I will update the summary again to reflect your comment. I think using diamond films is a great idea. They are more cost effective and free from the flatness issue.
Summary-updated:
(1) Natural stones like Arkansas (quartz, silicate, or novaculite) may not be the first choice when sharpening high carbide volume steels.
(2) You can use any good ceramic stones (alumina and above) for a coarse finish above 10 micron or below #1,000 ANSI grit.
(3) You would need abrasives harder than carbides for finer finishes, if you want to save time and effort. For vanadium carbide steels, this would be cubic boron nitride or diamond. Alumina and silicon carbide can still work but not efficiently. This may also apply to strops.
(4) Alternatively, one can use diamond lapping films instead of stones for finer finishes.
Miso
Last edited:
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DedboxHero,
YAH !
WOW ! ! !
Stellar post there. Or as I like to say with a Little Rascals inflection "THAT'S telling 'em".
hahahaha that's why I like you man, you crack me up
that's the one catch with diamond, You can't use it on steel with powered abrasive beltsor grinding wheels, Diamond is pure carbon just very uniform,compact and hard
you can't use those belts because carbon is very soluble in iron, it has a strong affinity for it. its bad for steel and the belts, that's reason why CBN is used in the industry for steel even though its not as hard it is inert and diamond is used for cemented carbides like certain cobalt alloys that don't react with iron.
This does not relate to sharpening stones, not enough friction and heat. Of course I doubt the work sharp has enough power to really cause problems but according to the industry its not the right abrasive for the job and even worksharp clearly states "not for use on steel knives, ceramic only'