Sharpening stones to use with modern powder steels

[microtech85]

I enjoyed the vids, and no offense meant but seems like spending a lot of time arguing against a straw man that nobody disagrees with. You are not doing a full edge profile like I did in my test, you are simply touching up and re-apexing an already nicely beveled edge. I don't expect too many folks here would think you couldn't get that blade sharp under those conditions. You say in one of these vids: there's a lot of chatter about whether ceramics can sharpen these steels. Not really. I'm not aware of many folks in the forums that would argue that ceramics cannot sharpen HC steels at all. A lot of the regulars here already use ceramics in some way themselves, for instance it's common to use ceramics as a niche role to refine an edge at the end of sharpening process. Clearly, ceramics "can" cut steel. But it's also true that you "can" use your toothbrush to clean your garage floor, but I doubt you'd want to.

The really interesting question I think is whether ceramics SHOULD be used in a primary sharpening role, and whether they are "optimal" compared to the other alternatives for sharpening HC steels. I get it that you would answer yes, but there are a LOT of pro sharpeners here who would answer no to this specific question. Myself, I'm undecided, but based on mixed results from years of earlier ceramic use and good recent success with diamonds and SiC, I am inclined in that direction. Your video does not speak to the issues raised in some of the other recent threads in the forum that raised significant detrimental issues when using ceramics with HC steels. See this thread as a recent example of the discussions. And my post here tried to summarize some of the issues. DM mentioned one--potential carbide tear-out which is still being debated on all sides, but there are others. If you want to do future interesting tests and videos that may have the chance of changing some minds, it would be interesting to instead do some tests that target the issues discussed in threads like the linked one, and see if you can show those concerns are either unfounded, or that there is a workaround. I am certainly open to new info myself, and always looking for ways to improve sharpening process and materials.

I think the conversation we are having is exactly what a forum should be; an exchange of information and ideas and opinions. And i like the civility of of discussion. But my goal isnt to tell anyone that there way is wrong. My goal is to share my experience and techniques. And you know my opinion on this topic by now. I too am open to new information. I always try to keep an open mind and think freely without constraints. And i always try to remain objective.
But i have both diamond stones and ceramics for a reason. They each are good for different things. At the moment though, i am not too keen on the carbide tear out theory. I am open to receive any good and convincing argument to prove me wrong though. I do not consider myself to be an authority on such things and i will always be open for a good civil debate. So thanks for debating the topic with me.

 

[maximus83]

I think the conversation we are having is exactly what a forum should be; an exchange of information and ideas and opinions. And i like the civility of of discussion. But my goal isnt to tell anyone that there way is wrong. My goal is to share my experience and techniques. And you know my opinion on this topic by now. I too am open to new information. I always try to keep an open mind and think freely without constraints. And i always try to remain objective.
But i have both diamond stones and ceramics for a reason. They each are good for different things. At the moment though, i am not too keen on the carbide tear out theory. I am open to receive any good and convincing argument to prove me wrong though. I do not consider myself to be an authority on such things and i will always be open for a good civil debate. So thanks for debating the topic with me.

Understood bro, all good. Keep doing those vids, but I just think they'd get REALLY interesting and have a chance of changing some minds--including mine--if you target some of the current hot issues that folks are discussing around ceramic usage. It is just not controversial that ceramics can work, I think everybody (or at least, mostly everybody) is already with you there, certainly I am.

Here's a great representative and recent post from the one of the regulars in the forum. The idea that ceramics can work, but there are better choices based on his sharpening background and business. Unlike myself--merely a weekend hacker who sharpens for fun and necessity --Jason actually knows what he's doing. I hear similar perspectives to his quite a bit on the forum.

 

[Chris "Anagarika"]

Max and microtech,

I like the civility of the discussion. Unfortunately lots of previous images from eKretz are gone. He did show the difference of using ceramic (Spyderco fused one) vs diamond. I recalled it’s an eye opener to me.

Finishing with extra light touch on Spyderco UF might help on S110V, but for my use it’s still done by DMT EEF prior to UF. And yet I haven’t been able to match M4, VG10, 52100 or 8Cr13MoV level of sharpness. Likely it’s me (also weekend tinkerer) and not the steel.

Jason is a pro, and very good at what he does. I think his key is his ability to hold consistent angle which is the fundamental aspect to achieve clean apex.

 

[HeavyHanded]

Max and microtech,

I like the civility of the discussion. Unfortunately lots of previous images from eKretz are gone. He did show the difference of using ceramic (Spyderco fused one) vs diamond. I recalled it’s an eye opener to me.

Finishing with extra light touch on Spyderco UF might help on S110V, but for my use it’s still done by DMT EEF prior to UF. And yet I haven’t been able to match M4, VG10, 52100 or 8Cr13MoV level of sharpness. Likely it’s me (also weekend tinkerer) and not the steel.

Jason is a pro, and very good at what he does. I think his key is his ability to hold consistent angle which is the fundamental aspect to achieve clean apex.

Chris, I couldn't link the pics in the original thread but did repost them in a recent thread:
https://www.bladeforums.com/threads...0-90-110v-or-not.1519674/page-3#post-17538256

Another thing to consider is the density of vanadium carbides. there is a huge difference between 3% and 9%. Methods that work on s30v or other relatively low vanadium content steel will have much less success on s110v or 10v etc. For anyone really curious about this and willing to beat up a higher end knife, try doing some surface work on the primary grind of a knife made from s110v. At lower grit values the work progresses, and then as you get up the 600-800 grit mark it stalls to a halt with mostly burnishing as the carbides protect the softer steel from penetration by the abrasives. Switch to diamond abrasives and it proceeds again at a respectable pace. The same effect is playing out on a microscopic scale along the apex.

 

[Rhodies]

I use the 5” dmt fine(red), then extra fine (green), then a single spyderco ultrafine triangle “stone.” Gentle touch, and just a few strokes, alternating sides with each stroke on each level. Total cost $50, and s30v, CT’s-204p, s35vn, my daily users, all come out painlessly dry shaving my beard, or tree topping sharp

I too have the green/red (fine/extra fine) except 8" DMT Plates. They work great if you are pressed for time. I do 6 - 8 strokes on each side and I'm make in business.

 

[microtech85]

Chris, I couldn't link the pics in the original thread but did repost them in a recent thread:
https://www.bladeforums.com/threads...0-90-110v-or-not.1519674/page-3#post-17538256

Another thing to consider is the density of vanadium carbides. there is a huge difference between 3% and 9%. Methods that work on s30v or other relatively low vanadium content steel will have much less success on s110v or 10v etc. For anyone really curious about this and willing to beat up a higher end knife, try doing some surface work on the primary grind of a knife made from s110v. At lower grit values the work progresses, and then as you get up the 600-800 grit mark it stalls to a halt with mostly burnishing as the carbides protect the softer steel from penetration by the abrasives. Switch to diamond abrasives and it proceeds again at a respectable pace. The same effect is playing out on a microscopic scale along the apex.

Those are very nice and educational photos. Thank you for sharing. It looks as though the carbides are either being brushed over, pulled out or the matrix is cut so deep that they are concealed.
I said this a few posts earlier,
"I am thinking about this "carbide tear out" and it seems to me that the carbides are so much harder than the surrounding steel that when sharpening with a diamond or anything else, the metal around the carbide would be worn away long before the carbide could be sharpened and would therefore will be abraded away." i think it still stands. we all knowhow big a differencethere is in a knife treated to rc56 and one to 60rc. carbides are an order of magnitude harder from waht i could gather. something lik rc75 or higher, i think even 85. the materials lists that i found show hardened steel at 4 mohs hardness where carbides were between 9-9.5 mohs hardness. so i think that whether one uses diamond or ceramic, the enclosing steel matrix will be sharpened away before the carbide can even get close to being shsrpened. It looks like in the photos that the ceramic grazed over them where the diamonds just tore them out. That may be because the diamonds are set in softer nickel plate which may tear out the carbides. Where ceramic is uniform hardness so the carbides cant cut as deep into the harder ceramic as they can into the nickel plate that the diamonds are adhered to. What do you think of this theory?

 

[HeavyHanded]

Those are very nice and educational photos. Thank you for sharing. It looks as though the carbides are either being brushed over, pulled out or the matrix is cut so deep that they are concealed.
I said this a few posts earlier,
"I am thinking about this "carbide tear out" and it seems to me that the carbides are so much harder than the surrounding steel that when sharpening with a diamond or anything else, the metal around the carbide would be worn away long before the carbide could be sharpened and would therefore will be abraded away." i think it still stands. we all knowhow big a differencethere is in a knife treated to rc56 and one to 60rc. carbides are an order of magnitude harder from waht i could gather. something lik rc75 or higher, i think even 85. the materials lists that i found show hardened steel at 4 mohs hardness where carbides were between 9-9.5 mohs hardness. so i think that whether one uses diamond or ceramic, the enclosing steel matrix will be sharpened away before the carbide can even get close to being shsrpened. It looks like in the photos that the ceramic grazed over them where the diamonds just tore them out. That may be because the diamonds are set in softer nickel plate which may tear out the carbides. Where ceramic is uniform hardness so the carbides cant cut as deep into the harder ceramic as they can into the nickel plate that the diamonds are adhered to. What do you think of this theory?

All speculation on my part here, especially as some report very different outcomes.

I believe the biggest difference is the diamonds bust the carbides relatively cleanly in place and the ceramics cannot. They wear them down and once they get shallow enough they fall or are hooked out. The diamonds can chop the carbides and leave the rest behind with a smaller attachment bond, so less tearout and less force needed to effect the carbides in the first place. It can cut smaller pieces off when they are partially excavated and leave smaller pieces behind when they are more exposed.

 

[Obsessed with Edges]

All speculation on my part here, especially as some report very different outcomes.

I believe the biggest difference is the diamonds bust the carbides relatively cleanly in place and the ceramics cannot. They wear them down and once they get shallow enough they fall or are hooked out. The diamonds can chop the carbides and leave the rest behind with a smaller attachment bond, so less tearout and less force needed to effect the carbides in the first place. It can cut smaller pieces off when they are partially excavated and leave smaller pieces behind when they are more exposed.

^This. I view it as a 'wrecking ball' versus a cutting tool, in determining how the harder carbides will be handled. One just knocks them loose, more-or-less whole, while the other will cut more cleanly through them, leaving a portion in place.


David

 

[smilk327]

I was thinking of this very same thing the past few days. I came up with the following. Please if anyone thinks this isn't right let me know before I purchase this set up.
Dmt six in double sided xc/c plate(no holes)
Dmt six in double sided f/ef plate (no holes)
Spyderco fine benchstone
Spyderco ultra fine bench stone
Dmt holder as mentioned in op
And a strop with green compound, flex cut gold, mothers mag, and bare leather.
Thoughts? Any info will help.

Current set up is a harbor freight four sided diamond(200, 300, 400, 600) stone
Spyderco fine bench stone. Uf sharpening rod and the strop mentioned above.