S30V 1K SiC and UF abraded surfaces

[BluntCut MetalWorks]

Below 600 grit, I mostly want to plow/excavate steels, so sharp+cheap abrasive works best for me. SiC waterstone satisfied both cheap & sharp. Diamond offers short-live sharp, therefore ain't cheap. At this coarse grit - Sharp SiC works better than dulled diamond.

...

At the coarse end of the spectrum: Is it conceivable you'd get the best possible results with high carbide blades, if you just used diamonds end-to-end, not even using a SiC stone for the coarse work? Just speculating here, but interested because I've been using my Crystolon for all my coarse work (regardless of steel type) recently. It certainly works. But if we're going for "optimum results" on high carbides, and only diamonds/cbn will cleanly abrade the carbides, it seems like the quality of the edge finish that you get from your coarse stone sharpening might be better if you used diamonds there, too. Which would lay a better foundational edge for your later sharpening.

Thoughts?

 

[HeavyHanded]

At the coarse end of the spectrum: Is it conceivable you'd get the best possible results with high carbide blades, if you just used diamonds end-to-end, not even using a SiC stone for the coarse work? Just speculating here, but interested because I've been using my Crystolon for all my coarse work (regardless of steel type) recently. It certainly works. But if we're going for "optimum results" on high carbides, and only diamonds/cbn will cleanly abrade the carbides, it seems like the quality of the edge finish that you get from your coarse stone sharpening might be better if you used diamonds there, too. Which would lay a better foundational edge for your later sharpening.

Thoughts?

At the coarse end it really doesn't seem to make a difference right up to the fine Crystalon and maybe a little beyond. At least there is no appreciable difference, and if there is no anecdotal change you are unlikely to find one with less subjective testing. I've gotten very nice edges off the Crystalon.

In theory you want the "softer" friable abrasives at the coarse end for your set-up, as these will cause the least subsurface carbide/crystal lattice displacement. In practice I'm not sure there is going to be a big difference, especially if you are grinding away all trace of the deeper scratches. If stopping at a coarse level, a diamond plate in good shape should give you better results. Testing this vis a vis might be tough because again, you cannot really compare apples to apples when one of the apples is an orange.

When resetting a bevel on high carbide steels where there is a significant angle change I use a diamond plate.

 

[BluntCut MetalWorks]

In addition, For nicer cosmetic(production edge) - I use coarse diamond plate to minimize unruly scratches above the bevel shoulder because there are hardly any loose grits compare to stones that shed grit.

...
When resetting a bevel on high carbide steels where there is a significant angle change I use a diamond plate.

 

[maximus83]

So you guys just named 3 cases--clipped below--where diamonds even for the coarse work would make sense. HH's first case is the one I had in mind. I've been doing this general approach lately regardless of steels: sharpen on a good coarse stone, then finish with Spydie UF and strop. It seems like for coarse work either SiC or diamonds work, but in the case of personal knives where the coarse is the last stone I will use, AND I don't want to booger the finish about the shoulder with those feathering scratches you get from SiC (ask me how I know ), then it seems like there are cases with high carbides where end-to-end diamonds/cbn are the best call.

So it sounds like the main objections to using diamonds end-to-end boil down to:
* Folks subjectively prefer using stones rather than diamond plates (I get that one, and agree with it, I like using my AF and even my Crystolon, mainly for the feel/feedback of the stone).
* Cost, per bluntcut: SiC is cheaper than diamond. BluntCut MetalWorks , I'm not sharpening anywhere near your volume I'm sure. But I'll just say in practice, I sharpen quite a bit maybe compared to an average knife owner, and I have yet to see a noticeable drop in sharpness of my diamond plates even the ones I've been using for 8 years.

Thanks guys, really interesting discussion.

[...]If stopping at a coarse level, a diamond plate in good shape should give you better results.
[...]
When resetting a bevel on high carbide steels where there is a significant angle change I use a diamond plate.

For nicer cosmetic(production edge) - I use coarse diamond plate to minimize unruly scratches above the bevel shoulder because there are hardly any loose grits compare to stones that shed grit.

 

[Chris "Anagarika"]

Thanks for the nice discussion.

Luong, no wonder I struggled with S110V using that worn EEF, and going back to rarely used EF and EEF (bought the diafold) works better. No hair splitting yet, or equal to VG10, but it is better.

Do you suppose for touch up, after light use (coffee pack, paper), ‘burnishing’ with worn EEF is sufficient or I better go with newer EEF? Reason is I found the result of new EEF still a bit coarser than I like (probably not worn enough).

 

[BluntCut MetalWorks]

S110V

@dmt EE

dulled 3um = can be 0.5 to 1um rounded cutting tip, so it will burnish at low psi and could jar matrix & carbides on higher psi.

sharp 3um = 0.25-0.5um cutting tips

However both due to surface undulation of diamond dotted plate, a few high points will greatly amplified psi, so end up with uneven burnish or deep scratch pattern.

True clean hair whittling edge would slice/draw-whittle. Edge with 3-5um holes (from fracture and or coarse jagged) would whittle hair by trap and scrape, so when slice/draw it would pull+cut or slip off.

@To match VG10 edge and more durable - I would try
Make a bunch of glass plate coated (maybe CA would work as binder) with 0.25um diamond powder and perhaps 0.1um as well.
Sharpen best as possible with EE, then flatten apex with EE by draw-scrape - check with loupe until apex is very flat and probably width will be around 1-1.5um.
Sharpen with coated glass plate - cutting tips will be small enough to effectively abrade/shape beyond normal straight razor edge. first time might takes 20-30 minutes. Touch up will be much faster.

Thanks for the nice discussion.

Luong, no wonder I struggled with S110V using that worn EEF, and going back to rarely used EF and EEF (bought the diafold) works better. No hair splitting yet, or equal to VG10, but it is better.

Do you suppose for touch up, after light use (coffee pack, paper), ‘burnishing’ with worn EEF is sufficient or I better go with newer EEF? Reason is I found the result of new EEF still a bit coarser than I like (probably not worn enough).

 

[Chris "Anagarika"]

S110V

@dmt EE

dulled 3um = can be 0.5 to 1um rounded cutting tip, so it will burnish at low psi and could jar matrix & carbides on higher psi.

sharp 3um = 0.25-0.5um cutting tips

However both due to surface undulation of diamond dotted plate, a few high points will greatly amplified psi, so end up with uneven burnish or deep scratch pattern.

True clean hair whittling edge would slice/draw-whittle. Edge with 3-5um holes (from fracture and or coarse jagged) would whittle hair by trap and scrape, so when slice/draw it would pull+cut or slip off.

@To match VG10 edge and more durable - I would try
Make a bunch of glass plate coated (maybe CA would work as binder) with 0.25um diamond powder and perhaps 0.1um as well.
Sharpen best as possible with EE, then flatten apex with EE by draw-scrape - check with loupe until apex is very flat and probably width will be around 1-1.5um.
Sharpen with coated glass plate - cutting tips will be small enough to effectively abrade/shape beyond normal straight razor edge. first time might takes 20-30 minutes. Touch up will be much faster.

Thank you!
At least it’s now confirmed what isn’t right (and not totally operator error, except selecting wrong abrasive )

 

[maximus83]

One thing that still doesn't make sense to me, to this day.

Let's assume for sake of argument that carbide tear-out occurs when using ceramics on high carbide steels, is significant and harmful to your edge, and is well understood. (I realize that's NOT the case that everyone buys that, but let's assume that savvy companies in the knife, steel, and abrasive industries are at least aware of this issue).

If that's true: Why would a company like Spyderco continue to use ceramics as primary sharpening tools in Sharpmaker, and even in their new DoubleStuff 2 stone that they spent a lot of time and expense developing and bringing to market? Surely they are at least aware this issue exists. Further, a majority of their medium and higher end new knives are using super steels, so you'd think that in their primary sharpening tools they offer to end users, they'd be offering abrasives that can adequately deal with these steels and keep them sharp.

Obviously they've already acknowledged and partly dealt with this issue: they provide medium-coarse diamond or cbn SM rods, and in the new DS2 stone, a similarly coarse cbn abrasive side. The problems with these are mainly that there's only a single-grit offering, and here's the biggie...they continue to rely on ceramics as the higher-grit refine-and-finish option. That has not changed, even in the outstanding (I have one and reviewed it--and even like and recommend it) new DS2 stone.

So given all that, speculate with me. Spyderco wants its users to be able to sharpen their fancy super steel knives. So.....why do they continue using ceramics? My theory is that (1) they reject the theory of carbide tear-out with ceramics as unproven, and (2) it's also about cost: developing a 2-grit, dual-sided cbn or diamond stone that is high quality and long-lasting might get prohibitively expensive for such a small stone.

 

[FortyTwoBlades]

I don't really think it's any of those factors. They started off as a sharpening stone company with sintered ceramics and have continued to operate in that range of the market largely because they're one of the biggest players in that market sector. It's not because they work better or worse, but rather a matter of their market positioning. Other options exist out there for folks not looking to use sintered ceramics, and I don't think they were keen on the idea of competing with established manufacturers like Norton when they had their own little niche nicely carved out.

 

[maximus83]

^Plausible 42. But at some point, unless they are just rejecting the whole carbide tear-out thing as false and irrelevant, one would think they will need to update their abrasives strategy to changing technology and market conditions, true? Super steels are increasingly becoming standard steels, and I'd think their sharpening solutions to stay competitive will eventually need to align to that reality. Again, the exception to that is if they've researched all this, and have what they consider strong evidence that carbide tear-out with ceramics is a non-issue. If that's the case, I'd LOVE to see the evidence and reasoning on that, because I personally like using ceramics for some things and would like to know if they can still really be a viable option for super steel sharpening.

 

[FortyTwoBlades]

^Plausible 42. But at some point, unless they are just rejecting the whole carbide tear-out thing as false and irrelevant, one would think they will need to update their abrasives strategy to changing technology and market conditions, true? Super steels are increasingly becoming standard steels, and I'd think their sharpening solutions to stay competitive will eventually need to align to that reality. Again, the exception to that is if they've researched all this, and have what they consider strong evidence that carbide tear-out with ceramics is a non-issue. If that's the case, I'd LOVE to see the evidence and reasoning on that, because I personally like using ceramics for some things and would like to know if they can still really be a viable option for super steel sharpening.

Not really...sintered ceramics will work fine on all but exotic high-vanadium steels, so there's simply no need to "update" them. Most steels are, and shall remain, within the range where aluminum oxide is more than hard enough of an abrasive to handle anything thrown at it. I really doubt that we're going to see high-vanadium steels become the norm, so there's really zero need to change what's working and will continue to work. And, as you mentioned, they do have CBN and diamond options.

 

[maximus83]

Not really...sintered ceramics will work fine on all but exotic high-vanadium steels, so there's simply no need to "update" them. Most steels are, and shall remain, within the range where aluminum oxide is more than hard enough of an abrasive to handle anything thrown at it. I really doubt that we're going to see high-vanadium steels become the norm, so there's really zero need to change what's working and will continue to work. And, as you mentioned, they do have CBN and diamond options.

I dunno, the super steels are becoming increasingly common. Heck even "mainstream" super steels like s30v, bluntcut's OP shows the carbide tear-out occured with a straight-up spyderco UF ceramic. S30v or s35, these are even showing up in $50 to $80 knives, 2 great examples I own are Buck Vantage Pro and Spyderco Native 5. M390, I just recently bought in a $79 Kershaw Link, and I bet within a couple years, 20cv and M390 steels will increasingly become mainstream. I think they are already fast becoming mainstream, unless you're defining "high vanadium steels" as only the extremely high ones like S90v/s110v.

 

[Chris "Anagarika"]

I think it’s because most people can’t tell the difference in actual daily use. I’m in the minority that insist to use my knife to dry shave. That’s the reason Luong gave that answer to help my particular requirement. It’s just that the freshly finished edge I’m getting is behind VG10, both done on same EEF, edge leading (to remove burr), to shave daily. If I wait until 2 days, the S110V works too, because the skin / hair has normalized. Use it daily, it fails to clean the just growing back hair with sensitive skin.

If used for real cutting, my Manix S110V has worked very well, even finished on dull EEF.

 

[maximus83]

^So Chris, you think that Spydie knows about the issue, but is in the group that says so what, it doesn't make enough real world difference to matter?

This brings the question back to our thread, and Bluntcut's OP. Spydie is not a dumb company. I happen to like them a lot. So are they right? Even if carbide tear-out occurs, does it not really matter to most real world knife usage, and so all our haggling about it here is just debating about how many angels can dance on the head of a pin? If they are right, maybe we should just stop thinking about it, and start using ceramics ourselves at least in a finishing/refining role, as it apparently is only detrimental to special cases like surgical instruments, cutting competitions, and trying to shave facial hair with folding knives. Or if it really DOES matter, then it seems IMHO like Spydie seriously needs to update their abrasive strategy.

 

[FortyTwoBlades]

I dunno, the super steels are becoming increasingly common. Heck even "mainstream" super steels like s30v, bluntcut's OP shows the carbide tear-out occured with a straight-up spyderco UF ceramic. S30v or s35, these are even showing up in $50 to $80 knives, 2 great examples I own are Buck Vantage Pro and Spyderco Native 5. M390, I just recently bought in a $79 Kershaw Link, and I bet within a couple years, 20cv and M390 steels will increasingly become mainstream. I think they are already fast becoming mainstream, unless you're defining "high vanadium steels" as only the extremely high ones like S90v/s110v.

Yes, I mean the extremely high ones. And I really don't think they'll become commonplace simply because they're of little real benefit in most circumstances since the more strict requirements in sharpening equipment drastically decreases the convenience that increased abrasive wear resistance provides. Most people don't really need it, and it makes it so that honing under all circumstances is impacted. The cost of those steels is largely in the machining--it takes more in the way of abrasives to do the machining work on those steels. Meanwhile, one can get a large degree of abrasive wear resistance from steels with high amounts of chromium carbides like ZDP-189 or D2 that are still able to be sharpened using aluminum oxide stones without issue.

 

[maximus83]

OK, but I think the issue remains that even with...let's say...."moderate vanadium content" steels , like S30/s35/M390/20cv, these most definitely are mainstream and widely used. And I think carbide tear-out with ceramics is shown to be an issue even on these, at least judging from some of the photo evidence here. Whether it MATTERS, of course, is up for grabs. So I don't think the issue applies only to relatively rare s90/s110 blades. The options are either you argue that the tear-out with ceramics doesn't occur at all (as Todd S has argued here in the forums), or it occurs but doesn't matter to real world knife users (I'm interested in this possibility), or it occurs and DOES matter, so quit using ceramics on these steels, and stick with diamonds for high-grit finishing abrasives.

 

[Chris "Anagarika"]

Max,

It matters in the photo shared here, but in cutting the miles of cardboard like what Jim does in his test? I think it’s wait & see. I’m guessing when more people start noticing this effect, diamond waterstones will be in more demand. Those that Shawn / DeadboxHero plays with. If there’s demand then someone will produce the stones needed.

Let’s not forget that we’re in the minority here. Most people live with dull knives that won’t even slice copy (not phonebook) paper. In this context a freshly sharpened S30V on alox is SHARP for them, and those mini / micro carbides out doesn’t matter. When the edge deteriorated to working level after few initial cuts, the apex would be rounded enough & abraded enough that the other carbides come into play.

Again, this is speculation on my part.

 

[FortyTwoBlades]

OK, but I think the issue remains that even with...let's say...."moderate vanadium content" steels , like S30/s35/M390/20cv, these most definitely are mainstream and widely used. And I think carbide tear-out with ceramics is shown to be an issue even on these, at least judging from some of the photo evidence here. Whether it MATTERS, of course, is up for grabs. So I don't think the issue applies only to relatively rare s90/s110 blades. The options are either you argue that the tear-out with ceramics doesn't occur at all (as Todd S has argued here in the forums), or it occurs but doesn't matter to real world knife users (I'm interested in this possibility), or it occurs and DOES matter, so quit using ceramics on these steels, and stick with diamonds for high-grit finishing abrasives.

It's worth noting that we're dealing with a single photo, and presuming that the interpretation of it being tearout is correct, not to mention not knowing all the details of the variables involved in the process that got the edge to that state. I'd say we'd need a MUCH larger body of evidence before drawing solid conclusions.

 

[maximus83]

It's worth noting that we're dealing with a single photo, and presuming that the interpretation of it being tearout is correct, not to mention not knowing all the details of the variables involved in the process that got the edge to that state. I'd say we'd need a MUCH larger body of evidence before drawing solid conclusions.

Yes that is spot on. We DEFINITELY don't have much evidence one way or the other so everything is kind of tentative. My problem is, the photographic evidence is so clear from this and the other photos I've seen, I don't know of a better/contrary explanation for the case of the missing carbides. If somebody has one, I'm super interested to hear it and hope they will post it.

 

[FortyTwoBlades]

I think it's less clear than you think it is. That's just the way that you've chosen to interpret the picture, when it's possible that it looks the way it does for completely different reasons. Also, while I think it's possible for tearout to occur with carbides, it'd be VERY strange if that occurred due to the ceramic because the ceramic is not a "grabby" abrasive and if the force used really was minimal then that low of a side-load means that the tearout would have happened in wood or cardboard, too, so the problem couldn't possibly be the ceramic from what I can fathom. If there's really a problem of tearout here I expect it's from the stages leading up to the ceramic.