Help picking Edge Pro grit progression for s90v and 154cm please.

[jeffbird]

Though it may seem to work, Silicon carbide stones are not actually hard enough to properly cut through the very hard vanadium carbides. With a Knoop hardness of 2480 and a vanadium carbide hardness of 2660 you can see why Diamond at 7000 is the much better choice.

With 180 points of difference the Silicon carbide is is hardly capable of grinding through the hard carbides in the steel resulting in an inferior edge. It will sharpen it, but there will be a lot of wasted energy in the process and obtaining proper levels of sharpness will be difficult at best.

Ankerson and Phil Wilson have discussed this subject on here before. Phil uses and recommends Norton Crystolon stones and I can personally attest that his knives as delivered are quite sharp. I can also personally attest that the Moldmaster stones as suggested by Ankerson are quite capable even on my Phil Wilson made of V10 at Rc 66. Also, the Moldmaster stones cut much quicker than the EP stones that came with it. A S110V from Phil is a bit slower to sharpen, but the MM's still handle it fine. S35V on a Hinderer is no big deal at all as another reference point fwiw.

It takes longer to set up and soak the stones, than it does to take the knives to hair shaving sharp. fwiw, I have diamond stones as well and while they are good and useful, they sit in the closet unused based on trying both.

Also, while mirror and super micro finished edges are entertaining as a challenge for playing with paper, in my use on cleaning animals, they have proven to be not worth the effort and actually inferior for holding a useful edge.

I understand your science, but there is something else at work based on hands on experience.

 

[beady]

Thanks for all the comments and advice.

I ended up going with an Atoma 400 and 1200 and a Shapton Glass 4k. I’ve sharpened one of my Henckels kitchen knives and my Benchmade HK 14205 so far, and have gotten a far, FAR better edge than I have ever managed with the original EP 220 and 320 stones. The 4K stone leaves almost a mirror finish on the bevel, and touching the sharpened edges almost makes your hair stand on end, lol. I put both blades to 17 degrees per side and have used the Henckel for slicing up some onions, carrots and a bell pepper and it performed much better than when it was new.

I’ll try out the 14205 tomorrow peeling and slicing an apple at work.

I think I’m going to pony up for an Atoma 140 as well; I didn’t realize how much work it was going to take with the 400 getting the bevel where I wanted it.

Very satisfied and impressed with the Atoma/Shapton combo on the Henckels steel and 154cm on the 14205. I’ll try a few other knives before I try my hand on the 940-1.

Mike

 

[jeffbird]

Jason B.,

In looking through old posts on this subject, there seemed to be differences reported between DMT and Atoma plates. The plates I have and used were DMT's.

In an effort to keep an open mind and keep on learning and improving, I ordered a set of Atomas to try.

If I can see a difference, I'll post it up and give you the credit for nudging me.

A Phil Wilson S110V will be first up since it is the slowest for me to sharpen.

Tip of the hat to you sir.

 

[sodak]

Though it may seem to work, Silicon carbide stones are not actually hard enough to properly cut through the very hard vanadium carbides. With a Knoop hardness of 2480 and a vanadium carbide hardness of 2660 you can see why Diamond at 7000 is the much better choice.

With 180 points of difference the Silicon carbide is is hardly capable of grinding through the hard carbides in the steel resulting in an inferior edge. It will sharpen it, but there will be a lot of wasted energy in the process and obtaining proper levels of sharpness will be difficult at best.

How about the waterstones that come with the EP? I have reprofiled and sharpened my Spyderco PW Southfork (S90V), and put a polished edge on it (for fun), and the edge looks clean under 100x magnification, and it was relatively quick. This looks to me as one of those things that theoretically shouldn't work, but it seemed to work for me.

Would a diamond plate have been quicker/better? Ceramic?

Bueller? Bueller? ...

 

[Jason B.]

I can sharpen S30V on a King waterstone, can you explain that?

I'm not sure what you want me to say, I'm presenting facts. I will continue with intelligent discussion if you like but I'm not going to argue a hearsay rebuttal.

 

[yepimonfire]

Ankerson and Phil Wilson have discussed this subject on here before. Phil uses and recommends Norton Crystolon stones and I can personally attest that his knives as delivered are quite sharp. I can also personally attest that the Moldmaster stones as suggested by Ankerson are quite capable even on my Phil Wilson made of V10 at Rc 66. Also, the Moldmaster stones cut much quicker than the EP stones that came with it. A S110V from Phil is a bit slower to sharpen, but the MM's still handle it fine. S35V on a Hinderer is no big deal at all as another reference point fwiw.

It takes longer to set up and soak the stones, than it does to take the knives to hair shaving sharp. fwiw, I have diamond stones as well and while they are good and useful, they sit in the closet unused based on trying both.

Also, while mirror and super micro finished edges are entertaining as a challenge for playing with paper, in my use on cleaning animals, they have proven to be not worth the effort and actually inferior for holding a useful edge.

I understand your science, but there is something else at work based on hands on experience.

Even on regular steel knives if hardly call crystolon a good sharpening material and would only use it to fix a damaged edge. The final edge left behind is just too rough, and even the fine stone is like 280 mesh, most initial grits are that low for repairing damaged edges. Secondly if you're saying a finer edge has worse edge holding ability you must be doing something wrong. On almost every knife I've owned taking it down to super fine has given me almost twice the working edge time, medium and rougher edges tend to fall apart more rapidly and unless all you plan on doing is sawing there is virtually no cutting advantage, in fact, going down to .5 micron diamond I don't need to saw, it just goes right through even fibrous material. At the low grits of crystolon stones you're probably not noticing a difference because you're tearing the carbides right out and the actual scratches in the edge are probably as large or larger then the vanadium carbides. Lastly, even the 8000 grit diamond isn't something i would consider super fine. It's more akin to a 3-4k water stone due to its aggressiveness and the fact it's measured in mesh, not jis. If you really wanna see what a highly polished edge can do, progress up and then finish with 2 and 1 micron diamond paste. It may take longer, but a very refined edge does indeed hold its integrity longer on every knife I've tried it on, even soft cheap kitchen knives. If you look at electron microscope photos at various grits, you can also see that below 4k on a naniwa (8k on your diamond), the edge never reaches a true apex. I can also attest personally that on my s30v knives the edge does not come off polished quite right from an 8k waterstone the same way I'd get from non vanadium steels, only after stropping with diamond does it truly become what I'd call finished. It will sharpen the steel, and to a certain grit just tear out the carbides, but will never polish the entire edge including the carbides. From what I hear, s60v, s90v etc get worse with this as the vanadium increases.

 

[sodak]

I can sharpen S30V on a King waterstone, can you explain that?

I'm not sure what you want me to say, I'm presenting facts. I will continue with intelligent discussion if you like but I'm not going to argue a hearsay rebuttal.

I was just asking for your opinion, that's all.

What I've seen in the past is that when some things "shouldn't" work and sometimes do, that's an opportunity to learn more about that particular area. It usually means that our understanding of a particular process is incomplete. For me, D2 is still an enigma. It "shouldn't" sharpen up as nicely as it does, but (with my knives), it takes a great mirror polish that is quite capable of shaving my face. But the conventional wisdom is that it shouldn't. I have no idea why. I'm not arguing for or against a mirror polish, I just like experimenting with D2.

 

[sodak]

Even on regular steel knives if hardly call crystolon a good sharpening material and would only use it to fix a damaged edge. The final edge left behind is just too rough, and even the fine stone is like 280 mesh, most initial grits are that low for repairing damaged edges. Secondly if you're saying a finer edge has worse edge holding ability you must be doing something wrong. On almost every knife I've owned taking it down to super fine has given me almost twice the working edge time, medium and rougher edges tend to fall apart more rapidly and unless all you plan on doing is sawing there is virtually no cutting advantage, in fact, going down to .5 micron diamond I don't need to saw, it just goes right through even fibrous material. At the low grits of crystolon stones you're probably not noticing a difference because you're tearing the carbides right out and the actual scratches in the edge are probably as large or larger then the vanadium carbides. Lastly, even the 8000 grit diamond isn't something i would consider super fine. It's more akin to a 3-4k water stone due to its aggressiveness and the fact it's measured in mesh, not jis. If you really wanna see what a highly polished edge can do, progress up and then finish with 2 and 1 micron diamond paste. It may take longer, but a very refined edge does indeed hold its integrity longer on every knife I've tried it on, even soft cheap kitchen knives. If you look at electron microscope photos at various grits, you can also see that below 4k on a naniwa (8k on your diamond), the edge never reaches a true apex. I can also attest personally that on my s30v knives the edge does not come off polished quite right from an 8k waterstone the same way I'd get from non vanadium steels, only after stropping with diamond does it truly become what I'd call finished. It will sharpen the steel, and to a certain grit just tear out the carbides, but will never polish the entire edge including the carbides. From what I hear, s60v, s90v etc get worse with this as the vanadium increases.

Interesting, thanks. I'm going to have to break out my microscope and do some experimenting.

 

[HeavyHanded]

I was just asking for your opinion, that's all.

What I've seen in the past is that when some things "shouldn't" work and sometimes do, that's an opportunity to learn more about that particular area. It usually means that our understanding of a particular process is incomplete. For me, D2 is still an enigma. It "shouldn't" sharpen up as nicely as it does, but (with my knives), it takes a great mirror polish that is quite capable of shaving my face. But the conventional wisdom is that it shouldn't. I have no idea why. I'm not arguing for or against a mirror polish, I just like experimenting with D2.

D2 is an interesting steel. Differences in RC make a huge difference in how the edge functions at various finishes from my limited testing. Had an opportunity to compare the Eskabar D2 at approx 56-58 RC to one of forum member Bluntcut's D2 samples at approx 61 RC. The 61 RC will not only take a more acute edge, it holds it far longer. Conventional wisdom of keeping the inclusive relatively broad only applies to lower RC examples of this steel it would seem, as the Eskabar cannot hold the same inclusive anywhere near as well.

As for the mirror polish or not when working with D2, more or less irrelevant as once the tool sees any real use the carbides will kick in and determine longevity in conjunction with the primary/cutting angles (this is really true of all steel IMHO, with the largest variations aside from supporting angles coming from the composition and HT).

At any level of finish if prep'd well, there will be submicron cutting edge - one needn't drop to submicron abrasives to get there. At rougher levels of finish, the difference is there will be a lot more variation of the cutting line, and the percentage of the total edge length that is sub micron will be lower than a more refined finish.

This has the effect of increasing friction and also increasing the actual length of the cutting edge - as mentioned much of the edge will not be submicron, though along the edges of the grind trough exits and shallower exit points it will still be quite thin and highly usable. It will also exhibit greater friction when pressed into a target material. A finer finish will exhibit less resistance when pushed into a target material, and have less variation of cutting line to assist with catching when draw cutting.

If the target material parts more readily at a given amount of pressure with a draw or press, that will determine longevity in a practical sense. I have done plenty of testing to affirm this to myself - neither a highly polished edge nor a toothier one has a cutting advantage across every application - the better finish is application driven. The idea that a rougher edge is incapable of being a strong performer in an absolute sense is ridiculous. Careful work on the Norton Crystalon combined with some stropping using the reclaimed grit from the stone (as recommended by Phil Wilson) can produce a tree-topping edge with plenty of tooth for severing materials with a pull. The same thin ground, high RC and carbide reinforced edge will produce plenty of longevity at any finish. IMHO, the true advantage of the vanadium carbide rich steels is being able to grind them very thin at the primary and still have good lateral stability. One needn't prep them in any specific fashion to get the "most" as long as the primary is nice and thin - the application will determine the best finish just as it would with any other steel.

As for the OP's question, I am not familiar with all the EP offerings, but if going above 1200 or about 4k JWS it would be a good idea to switch to diamonds when sharpening the s90v, the 154cm can be sharpened with any common manufactured abrasive. Keep in mind, the hardness of vanadium carbide falls in a range, the very low end of which can be abraded with SiC if not AlumOx. However, it cannot be done with efficiency - at the high end of the range neither will be capable of more than superficial abrading if even that, and might as well be approached with the best tool for the job (diamond or CBN) if shooting for a bright polish.

 

[sodak]

HH,

Thanks, that's an interesting post! I have a lot more experimenting to do.....

 

[Jason B.]

I was just asking for your opinion, that's all.

What I've seen in the past is that when some things "shouldn't" work and sometimes do, that's an opportunity to learn more about that particular area. It usually means that our understanding of a particular process is incomplete. For me, D2 is still an enigma. It "shouldn't" sharpen up as nicely as it does, but (with my knives), it takes a great mirror polish that is quite capable of shaving my face. But the conventional wisdom is that it shouldn't. I have no idea why. I'm not arguing for or against a mirror polish, I just like experimenting with D2.

When sharpening steels with high volumes of vanadium carbides most any stone will abrase the steels matrix but only a few will actually cut through and shape the carbides. This allows the edge to be sharpened as a whole and not have resistance from the sharpening media. When a high volume vanadium carbide steel is sharpened on an abrasive media that is not hard enough to cut the carbide it polishes the carbide and this will result in an edge that is sharp but just not what it should be. When compared to other steels sharpened on the same stone there will be a noticeable difference in obtained sharpness and consistency. It's usually a rounded edge feel or a burr that just won't go away.

In the case of using coarser media like the Norton SiC stone it's simply a matter of the stone abrasive being larger than the carbides and just ripping them out along with the iron matrix. The same rounded edge with a lack of sharpness and a problematic burr will still be there just on a smaller scale because the stone is actually abrading the steel better than at finer grits. Lets use S90V as an example, I have sharpened my S90V Spyderco Military with the Norton Fine SiC stone and even got a reasonable edge. I had lots of trouble getting the edge to be clean and sharp off the stone but it was toothy and did cut very well despite needing to more pressure and movement to start and continue the cut. Now, change that up for a Coarse DMT stone and suddenly the edge is sharpening with ease and the edge straight from the stone is sharp enough to cleanly shave hair. IMO, its easy to see the difference is edge quality and keenness. For 90% of people using the Norton SiC on high V steels this stone and edge would surely seem adequate. Then again, my ideals of sharp are a few steps above what most consider sharp. The Norton SiC will get one by on high volume Vanadium steels but it's what I call getting by cheap, and when you try getting by cheaply it's usually because it's being done wrong. There is simply no argument with diamond or CBN being capable of effectively sharpened these steels.

D2 is a little different story, despite what is always said about the steel one of its main features is it's ability to take a fine polish. In the past you will hear many talking about the "orange peel" polish you get with D2 but this is due to the fact that the applied polish was improperly done. When polishing D2 it's easy to skip ahead too quickly and this will cause the steel to have a bumpy polish or "orange peel" finish.

 

[Obsessed with Edges]

I was just asking for your opinion, that's all.

What I've seen in the past is that when some things "shouldn't" work and sometimes do, that's an opportunity to learn more about that particular area. It usually means that our understanding of a particular process is incomplete. For me, D2 is still an enigma. It "shouldn't" sharpen up as nicely as it does, but (with my knives), it takes a great mirror polish that is quite capable of shaving my face. But the conventional wisdom is that it shouldn't. I have no idea why. I'm not arguing for or against a mirror polish, I just like experimenting with D2.

My take on D2 (non-CPM variety) specifically, is that the 'conventional wisdom', in saying it only takes a toothy edge and doesn't polish well, is the result of attempts to sharpen or refine it on inadequate abrasives, like natural (Arkansas) stones, or glazed stones, or inferior-grade stones in AlOx. The chromium carbides in D2 aren't as hard as AlOx, SiC or diamond; but, what makes them difficult is that they're so HUGE in the non-CPM versions of D2, up to ~50µ and even bigger at times. What Jason mentioned above, about the 'orange peel' effect being caused by jumping ahead too soon in grit progression, rings very true to me. Because the chromium carbides are so big, they need to be carved down in steps, with abrasives hard enough to handle it. I sort of look at these large carbides as if they were 'boulders' in the 'sand' of the steel matrix; if wanting to make the surface nice & smooth (i.e. 'polished'), the 'boulders' have to be chipped away in a decreasing progression of grit steps, as opposed to relying on harder but much smaller abrasive grit to get there quickly, as might work with smaller carbides. In practical terms, this means D2 is much, much easier to refine if using something like a Coarse > Fine > EF diamond progression to hone down the carbide size, after which it becomes much easier to finish polishing with something like AlOx compound or diamond pastes. So long as I make sure to do the 'grunt work' of grinding on diamond hones in sequence, D2 is EASY to polish and maintain, using AlOx compound on hard-backed denim (my favorite for D2, using white rouge), after which D2 takes some screaming-sharp, polished razor edges that hold up.


David

 

[sodak]

Thanks all for the info. Since these days I'm mainly using DMT, that's helping to explain my D2 sharpness. Apologies to the OP for the drift.

 

[HeavyHanded]

My take on the D2 orange peel effect is that it comes down mostly to what media one is using. Using a conformable media like a leather strop, or even balsa, will, over time or in short order if used often, induce this effect. The carbides are quite large, and the surrounding steel is soft by comparison. Over time the result of having a static amount of force applied from even a slightly conformable surface that is trying to expand back to its original volume, will be the surrounding steel worn away at a faster rate than the carbides. The effect at the onset might not be visible to the naked eye, but with a loupe and good lighting is apparent.

If one abuses their strop regimen, the visible erosion of steel around the carbides will become increasingly obvious, so in that sense skipping ahead would be a contributing factor. Only by using hard media can this effect be eliminated 100%, even diamond pastes are not a solution over other abrasives, so much as selecting a backing with zero give. The best advice IMHO is to avoid stropping at all with D2 beyond a few passes on plain leather or paper.

Many considerations re the vanadium carbide steels. I was a little surprised that the size of the average carbides in one sample of s30v I etched showed the bulk of them appeared to be equal to or less than 1 micron yet I had thought 3u was the average. Not sure what else to say about this but good for speculation. Also the carbides had only been worked on AlumOx prior to etching yet appeared flat across the top and the larger ones (still under < 3u) showed scratch marks across the surface.

I'm also in no position short of a true round-table discussion to speak to other folks definitions of sharp, but I have gotten s30v and s110v sharp enough to just whittle a hair and casually tree-top same using only SiC abrasives on a powered system and finished by hand - on s30v was able to do so with AlumOx as well. Switching to diamond for a final polish did reinforce/improve on these results to a notable degree, but only at the higher level of polish. Cut tests along the way showed good edge character at each progression.

This was following the existing geometry, attempts to effect the geometry and cosmetically influence the primary bevel beyond a fairly rough finish proved extremely frustrating - between the high RC and carbide reinforcement, polishing down progressed at a glacial pace. Initial work went at a good clip up to a satin finish.

Do not confuse these observations for my recommendation to use diamonds on high VC steels, critically at the finishing stage and preferably throughout. I am just pointing out that I see a bunch of factors in play when dealing with high carbide steels, vanadium or otherwise.

 

[sodak]

Got it, thanks.

 

[jeffbird]

Jason,

I tried the Atomas on a handful of knives today. Overall, they worked very nicely. The 140 must have a burr or clump of material as it leaves a pretty nasty scratch in one spot, but overall it is very nice. The 400 really is enough to finish most of the blades to a very nice edge. The 600 added a small bit, and the 1200 really did not seem to add much extra except on a chef's knife. The 400 produced edges which would cleanly cut phone book paper, which is good enough for my purposes. They are so clean to use and not making a mess of slurry is perhaps their best feature, which was really nice. Really liked them. Thanks for the nudge.