So how much better is a higher grade stainless?

[sodak]

Wow, Sodak that is a very generous offer. I am not sure I can accept that (though it is very tempting).

Nah, they were on sale for around $8, no big deal. Shoot me your address, I'll dig it up tonight and ship it off tomorrow.

 

[Broos]

You've got me thinking about something counterintuitive: Are the steels which need large angles to take polished finishes able to hold thinner edges with coarser finishes? It's counterintuitive to me because polished edges seem more resistant to chipping and corrosion for me.

If the test as very briefly described here previously is how edge stability is determined or measured, then I wonder IF it can be related to coarse edges. Doesn't it just make sense that a coarse edge is inherently less "stable" then a polished edge? Where does the optimum point lie between coarseness and stability?

 

[hardheart]

nah, you weren't obtuse, Thom. I was making a bad joke about not knowing Adam (I really don't know any, hmm) and typing out loud about options. I might email him for the info, just a little hesitant to ask a guy for his work kinda out of the blue. Dunno how that works, all the papers I've seen have either been through/for school work, or freely distributed online.

 

[thombrogan]

Downloaded the source for that cutleryscience blade materials page and searched all the links, but no luck yet. But I'm like a terrier, so not giving up yet....

A pit bull or like that dog on Frazier?

I think what you're suggesting is possible. Based on discussions I've read about the "self-sharpening" effect seen with some blades, it kind of makes sense to me that high carbide steel run at low angles could be more likely to microchip away, rather than wearing down more smoothly, and so keep a good level of slicing aggression. This sounds like an interesting little study for the Brogan Blade Testing Institute to conduct.

There's a problem with that institution: I tweak at the thought of leaving a blade with a coarse edge.

BTW, when I took my JYD2 down to 3.5" blade length, I had a strip of 13C26 from cutting down the spine with a Dremel cut-off wheel, and did a bit of testing on it. Amazingly tough for a stainless at that hardenss, can be bent to where it'll take maybe a 10-15 deg. set before breaking. I've done similar tests with VG-10 and it just snaps without flexing at all, and though all subjective doesn't seem to require near as much force.

That's very cool! When I rolled the edge on my External Toggle (same steel; same company; but a knife I like even better), the edge just rolled and looked all rolly (happened to a Swamp Rat Howling Rat, too, with the same rolly look), but when I've done the same on VG-10 and SG-2, it looked all cracked (which didn't happen when burring those steels during sharpening). Weird, different, and yet similar.

Been meaning to find out, I know the VG-10 Caly3 can't be disassembled, or the pivot adjusted. Same on the ZDP/cf version? Also wondering how sharp the jimping is; I really prefer a soft jimping like the JYD2, sharp jimping like on some of the Byrd line is a bit rough on bare skin for me.

The pivot on the VG-10/G10 Caly3 can be tightened, loosened, or even completely removed and thrown away (don't do it, though - it really helps the knife work better). The jimping is sharper than the JYDII, but it don't bite fingers like you may think and the pocketclip is my favorite pocketclip ever (though, if you get the G10/VG10 version, be sure so sand the G10 where the pocketclip contacts the scale or else the G10 will sand your pocket). The CF/ZDP one is more comfortable to use and carry clipped.

Sounds like you have a bit of a preference for the Super Gold over ZDP, true? I was really hoping Kershaw would do a run of SG-2 Leeks like was being discussed, I've gotten a hankering for a Leek and that seems like a great size and package for SG-2.

Didn't realize it, but, yes, I like it a little better. Easier and quicker to sharpen (not by much, though) and the edge lasts just as long with light cutting. The Leek is one of those knives that does great in ZDP-189 and 440A. That Onion guy is no Tim Galyean, but he knocks a few out of the park now and then. Seriously, the 440A Wally World Leek fits into the classic Cliff quote:

I'd rather have a Calypso Jr. made of AUS-4 than an Extrema Ratio made out of ZDP-189

In the Leek's case, you can get 440A, 13C26, S30V (why?!?!?! :barf: ), and ZDP-189 The problem for the user is to figure out whether it's the steel or the design that makes the knife work so well. When the JYD2 comes out with SG-2, it'll probably be more of the same.

Doesn't it just make sense that a coarse edge is inherently less "stable" then a polished edge? Where does the optimum point lie between coarseness and stability?

It does make more sense that a polished edge should be more stable, and yet we've read several opinions from folks who skin animals saying they prefer toothier edges. Even martensite/bainite bowie-user "the possum" uses a 150 grit AO stone (is that a Gerber puck, Mr. the possum?) for his knife that hits steel and stone on a regular basis (not on purpose - the critters he hunts duck and stuff).

I might email him for the info, just a little hesitant to ask a guy for his work kinda out of the blue. Dunno how that works, all the papers I've seen have either been through/for school work, or freely distributed online.

My experience has been to ask and either get help, a polite declining, or a lot of STFU/GTFO/ESAD, MF. You really won't know until you ask and the very worst he could do is kill you, clone your dna, and kill all of your clones (or merely say no).

 

[HoB]

I think the range of coarseness we can talk about here is rather interesting. When I say, I am looking to put a toothier edge on my knives. I am talking about between 1000 and 3000 grit as supposed to 8000-10000 grit. 150 grit to me is so unspeakable coarse that there is no way I could imagining leaving an edge like that, just like Thom I cringe at the thought. I want a knife, not a saw. Even for heavy rebeveling, I find 150 a bit on the coarse side. I am still not sure, whether I like the XX DMT stone. It cuts very fast but it leaves such a rough finish.

On the other hand, I don't think that carbide size will make much difference at 150 grit. At that grit we talk about a scratch pattern that is about 3 times larger than even D2 carbides, which also means that the teeth at the edge are likely perfectly capable of supporting those carbides.

 

[hardheart]

I guess we shouldn't be talking about filed edges, like I do with my golok, or my dad did with his Old Timers.

*evil laugh*

 

[thombrogan]

Hmm... going to have round up some files and anneal them in a pot of molten salt.

HoB,

One thing Gunmike1 and I both noticed is that edge angle plays a large factor in whether a specific grit feels toothy or polished. Convex an edge to 20 degrees per side or over with 2000 grit wet dry and it will feel fairly well polished. Leave an edge at 4-5 degrees per side with an 8000 grit stone and it will feel toothy.

As for rebevelling with the 120x D8XX, those scratches come right out with a 325 grit diamond or 500 grit waterstone (JoeC even has good luck removing them with a 700 grit Bester waterstone. Those 500 grit Glasstones are good, but some other stones are Bester).

 

[gunmike1]

Hmm... going to have round up some files and anneal them in a pot of molten salt.

HoB,

One thing Gunmike1 and I both noticed is that edge angle plays a large factor in whether a specific grit feels toothy or polished. Convex an edge to 20 degrees per side or over with 2000 grit wet dry and it will feel fairly well polished. Leave an edge at 4-5 degrees per side with an 8000 grit stone and it will feel toothy.

As for rebevelling with the 120x D8XX, those scratches come right out with a 325 grit diamond or 500 grit waterstone (JoeC even has good luck removing them with a 700 grit Bester waterstone. Those 500 grit Glasstones are good, but some other stones are Bester).

Yeah, on my Takeda Gyuto at 4 per side the 8000 grit finish felt and looked under magnification like a 2000 grit finish on 15 per side edge. It makes sense when you think of the angles, and how an edge at 1/2 the angle of another edge will have microteeth twice the size (first pointed out to me by Mr. Stamp).

The D8XX rules, and the D8C takes out the D8XX scratches pretty quickly. The speed of cutting for that stone is well worth any scratching you get.

Mike

 

[Dog of War]

A pit bull or like that dog on Frazier?

I have some friends who are seriously into Jack Russell terriers ... and smart as they are they've still got way more cojones than they do brains, tenacious as hell.

Actually I'm more like an old, yellow lab, sunning on the back porch.

That's very cool! When I rolled the edge on my External Toggle (same steel; same company; but a knife I like even better), the edge just rolled and looked all rolly (happened to a Swamp Rat Howling Rat, too, with the same rolly look), but when I've done the same on VG-10 and SG-2, it looked all cracked (which didn't happen when burring those steels during sharpening). Weird, different, and yet similar.

I've thought a number of times that the Sandvik steels are almost carbon steel-like in some ways, relatively speaking. Which isn't to knock VG-10 and others, just that the range of properties we see anymore in the stainlesses is pretty huge -- and a good thing, IMO, as more choices = more fun for us.

The pivot on the VG-10/G10 Caly3 can be tightened, loosened, or even completely removed and thrown away (don't do it, though - it really helps the knife work better). The jimping is sharper than the JYDII, but it don't bite fingers like you may think and the pocketclip is my favorite pocketclip ever (though, if you get the G10/VG10 version, be sure so sand the G10 where the pocketclip contacts the scale or else the G10 will sand your pocket). The CF/ZDP one is more comfortable to use and carry clipped.

Having never handled a ZDP Caly3 I wasn't sure, but that makes it a very, very desirable package IMO. Carbon fiber is my favorite synthetic handle material, and I much prefer wire clips. Oh, this could get expensive.

LOL! I'll be sure to remember that about folder pivots in the future!

Didn't realize it, but, yes, I like it a little better. Easier and quicker to sharpen (not by much, though) and the edge lasts just as long with light cutting. The Leek is one of those knives that does great in ZDP-189 and 440A. That Onion guy is no Tim Galyean, but he knocks a few out of the park now and then.

Like I said, this could get expensive.

When the JYD2 comes out with SG-2, it'll probably be more of the same.

Damn you, thombrogan! Anyone with an ARM that resets in the next few months would be bankrupt if they listened to you!

 

[Broos]

I guess part of my point was that edge stability should be referenced with some of the constraints that are used in determining it (you can say this for most measures of knife performance, too). And since I (we??) am not even aware of what the test is, it is probably premature to ask for what the constraints should be when using it! A coarse edge will complicate the matter of stability greatly, I think. A coarse edge will make the knife more prone to wear (lose material) from the edge - kind of ties back to the edge that stays toothy and cutting well despite wear. I suspect a toothy edge may have wear factors that are many times greater than looking at the same wear factor in a polished edge.

I would think there is a way to calculate the deepest depth of the micro-teeth based on the edge angle and avg size of abrasive - the angle will make a big difference here, especially at small blade/edge thicknesses (which will also vary due to the abrasive size). If your abrasive size is 40 microns, can a good sharpener achieve a consistent 1 micron edge with abrasives that large? In theory probably, in practice I don't know. Burr removal will also be much more difficult - it'll be tough to get to the burr at the bottom of the microteeth. Here is an edge where an observational measurement of sharpness (edge width) might not be as good as REST or other test to measure push cutting sharpness.

Has anyone done slicing edge retention tests with serrated blades? If 80 grit is good, maybe REALLY coarse is even better? Now those are some big honkin' microteeth!

And would these gigantic "micro-teeth" would be less likely to deform or chip than smaller micro-teeth?

 

[sodak]

Yes! Cliff found that D2 with a *really* coarse finish will cut almost forever. I'm discovering the same thing also.

 

[HoB]

Well, maybe I should have phrased that better. It is not so much that I don't get the scratches of the XX DMT out with a different stone, it's the roughness of the edge itself. I just used it early today and yes, it will rebevel in a hurry, but the burr....! It feels to me like what Jeff Clark always said: why pull up a burr when you have to chase it later? I wonder if what I am gaining in cutting speed is really worth it when I loose most of the time cleaning up the edge again. Well, I guess it is always a matter of how much work you've got to do. I am also convinced that a DMT will pull up a larger burr than a waterstone. I assume that the slurry of a waterstone grinds the burr away before it gets very large. I've noticed that already with the X DMT. Don't get me wrong, the XX DMT is still an amazing stone. The cutting speed is pretty impressive.

I have been able to remove the scratches of the XX DMT even with the Sharpmaker gray. Ok, it was a pretty soft steel, so it make take a while on a harder/more wear resistant steel, but it is possible. They are no match for the Bester 700.

The angle dependence of the finish isn't much of an issue for me, since, as I've said, most of my knives are all around 12 deg, a couple at 10 but that's not that much of a difference.

 

[gunmike1]

I usually cut straight into a stone to remove the massive burr raised by a major rebevel with heavy pressure from the D8XX. Once the main bevel has been set and the burr removed by cutting straight into a finer stone, the D8C refines the edge pretty nicely. I know what you mean about that burr though, it is sometimes a MASSIVE ragged hunk of steel hanging off the edge. That can be avoided by honing the very edge with a finer stone after doing the major work with the D8XX, but I found that cutting the burr off and going to the D8C works pretty good for me. I must admit though, sometimes even after cutting into the stone there is some residual burr left, and again the D8C can remove it by honing at a higher angle, then going back to your normal angle to reset the edge angle you want. I will put up with that burring for the ability to change a 15 per side ZDP 189 edge into a 10 per side edge in only a couple minutes. I really like the D8XX, and all but one of my knives has been rebeveled on it (the one I didn't use it on was about 9 degrees included, I figured that was thin enough).

Mike

 

[thombrogan]

It makes sense when you think of the angles, and how an edge at 1/2 the angle of another edge will have microteeth twice the size (first pointed out to me by Mr. Stamp).

Ya d00d! When abrasives dig or plow through steel, the effects are amplified when the point of intersection (what we Earthers call the edge) gets teenier.

I have some friends who are seriously into Jack Russell terriers ... and smart as they are they've still got way more cojones than they do brains, tenacious as hell.

The friends or the dogs?

Actually I'm more like an old, yellow lab, sunning on the back porch.

Yes, a yellow lab with more blades than a McCormick reaper.

I've thought a number of times that the Sandvik steels are almost carbon steel-like in some ways, relatively speaking. Which isn't to knock VG-10 and others, just that the range of properties we see anymore in the stainlesses is pretty huge -- and a good thing, IMO, as more choices = more fun for us.

The carbony effect you're seeing might well be the particle size and volume of the carbides that Larrin Thomas, Roman Landes, and Cliff Stamp have discussed. According to Larrin, AEB-L and 13C26 are similar to 52100 and Hitachi/YSS White Paper steel in terms of carbide size and volume as well as martensitic grain size and attainable hardness. Probably explains why me 13C26 Kershaws sharpen up so easily and don't do courtesy microchipping when the final edge (or microbevel) is below 30 degrees, too. Or in shorter sentences: Yeah, more fun for us like youse said!

Oh, this could get expensive.

It hasn't been financially taxing already? We must've have failed to reach you.

Damn you, thombrogan! Anyone with an ARM that resets in the next few months would be bankrupt if they listened to you!

Monsieur, you are too kind.

I guess part of my point was that edge stability should be referenced with some of the constraints that are used in determining it (you can say this for most measures of knife performance, too). And since I (we??) am not even aware of what the test is, it is probably premature to ask for what the constraints should be when using it!

Fair enough. Our current views of edge stability seem to involve the ability to perform pushcuts on soft, lightly abrasive material, so aside from chopping dirty potatoes or harvesting balsa wood, we might be left clueless. Maybe I can attribute cutting soft metals (copper, mild steel, extra spicy steel...) to edge stability (52100, 5160 bainite/martensite, and S7 all did it with no dulling, all of my high carbon high chromium knives chip on such things), but stability is such a transient term. Don't want to abandon it because it holds promise, but collecting the involved variables seems daunting (hats off to sodak and gunmike1 on that, though!).

A coarse edge will complicate the matter of stability greatly, I think. A coarse edge will make the knife more prone to wear (lose material) from the edge - kind of ties back to the edge that stays toothy and cutting well despite wear. I suspect a toothy edge may have wear factors that are many times greater than looking at the same wear factor in a polished edge.

I agree with you in that a polished edge will take less force to cut and as it degrades, its higher level of force may be lower than a 'sharper' coarse edge at the same angle, but on steels like S30V and D2, I read about knifemakers and users choosing low edge angles which often microchip when I use such angles, but their final polishes are generally lower (HoB notwithstanding).

I would think there is a way to calculate the deepest depth of the micro-teeth based on the edge angle and avg size of abrasive - the angle will make a big difference here, especially at small blade/edge thicknesses (which will also vary due to the abrasive size). If your abrasive size is 40 microns, can a good sharpener achieve a consistent 1 micron edge with abrasives that large? In theory probably, in practice I don't know. Burr removal will also be much more difficult - it'll be tough to get to the burr at the bottom of the microteeth. Here is an edge where an observational measurement of sharpness (edge width) might not be as good as REST or other test to measure push cutting sharpness.

I don't have the intellectual capacity to figure out how to do that. Though an EdgePro will likely let a 40 micron abrasive make the edge mentioned and allow for burr removal as well.

Has anyone done slicing edge retention tests with serrated blades? If 80 grit is good, maybe REALLY coarse is even better? Now those are some big honkin' microteeth!

I think Sal may have, but it's been a long time since I checked. A lot of really smart Spyderco users are cultish about their serrated knives; enough so to make me think it's more than doing it just to be different.

And would these gigantic "micro-teeth" would be less likely to deform or chip than smaller micro-teeth?

If my hair-brained, poorly articulated guess is correct, they may resist performance degradation even if their overall shape suffers deformity with more ease than highly polished edges.

Yes! Cliff found that D2 with a *really* coarse finish will cut almost forever. I'm discovering the same thing also.

Repeatability is good. Repeatibility is good. Repeatability is good. Re.. Seems to confirm what Cliff said and other points noted by Swaim and popular preference for a 'toothy' edge on high carbide steels.

Well, maybe I should have phrased that better. It is not so much that I don't get the scratches of the XX DMT out with a different stone, it's the roughness of the edge itself. I just used it early today and yes, it will rebevel in a hurry, but the burr....! It feels to me like what Jeff Clark always said: why pull up a burr when you have to chase it later?

You could always sharpen to just before the edge with the D8XX, get a little closer with the slightly coarser DMT or pink brick; border on the very edge itself with the Bester 700, and then do your actual sharpening and polishing with the non-pare, er, bluey stone and whatever your finishing jobby might be. Barely any burr chasing in 1K mud that breaks down into 3K mud is there?

The angle dependence of the finish isn't much of an issue for me, since, as I've said, most of my knives are all around 12 deg, a couple at 10 but that's not that much of a difference.

Come to the darkside! We'll intoxicate you with hibiscus. Or at least justify your purchases from Carter and Moritaka as medically necessary.

I usually cut straight into a stone to remove the massive burr raised by a major rebevel with heavy pressure from the D8XX. Once the main bevel has been set and the burr removed by cutting straight into a finer stone, the D8C refines the edge pretty nicely. I know what you mean about that burr though, it is sometimes a MASSIVE ragged hunk of steel hanging off the edge. That can be avoided by honing the very edge with a finer stone after doing the major work with the D8XX, but I found that cutting the burr off and going to the D8C works pretty good for me. I must admit though, sometimes even after cutting into the stone there is some residual burr left, and again the D8C can remove it by honing at a higher angle, then going back to your normal angle to reset the edge angle you want. I will put up with that burring for the ability to change a 15 per side ZDP 189 edge into a 10 per side edge in only a couple minutes. I really like the D8XX, and all but one of my knives has been rebeveled on it (the one I didn't use it on was about 9 degrees included, I figured that was thin enough).

Pretty sure you had that knife going at 8 degrees. Aogami Super; as heat-treated by the d00ds at Takeda Hamono; is, well, super!

 

[gunmike1]

Pretty sure you had that knife going at 8 degrees. Aogami Super; as heat-treated by the d00ds at Takeda Hamono; is, well, super!

It started out at 9 degrees from the factory (why such a fat angle?, this is a knife for God's sake), but the DMT coarse took it to 8 degrees when I was getting an alarming microbevel sharpening at 5 per side on my first sharpening session. At that point I went to 4 per side to get my 8 degree edge. I went with DMT coarse until I got a burr, then DMT fine, then 1K/2K/8K Glasstones, then 1 micron and .3 micron lapping films. The resultant very wide mirrored bevel cuts pretty good. I resharpened it again (it couldn't tree top anymore, way too dull for kitchen use) to .3 microns and it is very sharp for what my meager skills will allow. I almost cut myself with the three finger test, so I'm either careless or getting better at sharpening. Tomatos cry when they see it coming, as they know they are about to be guillotined into tiny pieces with no effort on my part. Now, if I could only find a way to not have to wash and dry it after every cutting chore it would be perfect. But yes, aside from no corrosion resistance, Aogami Super steel is a super steel in every sense of the word.

Mike

 

[HoB]

I would think there is a way to calculate the deepest depth of the micro-teeth based on the edge angle and avg size of abrasive - the angle will make a big difference here, especially at small blade/edge thicknesses (which will also vary due to the abrasive size). If your abrasive size is 40 microns, can a good sharpener achieve a consistent 1 micron edge with abrasives that large?

AHHHHH, now that is a very good and relevant question. Sorry I must have scrolled over this post or I would have answered earlier. It is actually very easy to calculate and the results are a real eyeopener: Forget about a 1 micron edge!.....well, rather, forget a 10 micron edge!

The calculation depends a bit on your starting assumptions. If you consider the surface of an abrasive (lets assume round abrasive particles, but that is not really a big assumption....well, when comparing with waterstones with have a "flaky" structure it might and it might be the reason why waterstones tend do be finer, but lets forget about that for a moment) and you assume the surface is perfectly regular, it will look like the left side in the picture:

The top of the particles will cut deeper and they will dig into the steel up to the baseplane. I think looking at the picture it is reasonable to assume that the baseplane will be about 1/4 diameter of the particle below the top of the particle. Especially if you put some pressure on it. But you can play around with the position of the baseplane. It will enter linearly. But this is of course an idealized case. In most cases there will be some particles that stick out a little higher than others like on the right side of the picture. If you assume that these particles stick out about 1/4 diameter over the lower particles - a reasonable assumption, I would say - you have a distance of 1/2 diameter between the highest and lowest points on the surface of the abrasive. If you now have an abrasive particle that has left the surface and rolles around on it. It might stick out (depending on the friability it might have broken down or not) up to more than one diameter over the surface.

Now the lowest valley you will get when two highpoints meet on from either side. This will be obviously 2x the highpoint-baseplane distance d The valley between a tooth and a valley is hence:

d=2*m*D/tan(phi)

D is the particle diameter and phi is half the edge angle and m is the mutiplier that determines the highpoint-baseplane distance.

In practice: If we assume that the highpoint-baseplane distance is 1/2 D (particle diameter) for a 40 micron particle as you say and we calculate this for 20 deg per side we get:

d=40/tan(20)=109 microns!

Now the tooth next to this valley could be shortened because a highpoint on one side may meet the baseplane on the other which would shorten the tooth by half. If we take the simple arithmetic average over the toothheight we get a rough estimate for the difference between a tooth and a valley of around 80 microns on average!!!

Now if you think that 1/2 D is too much for the highpoint-baseplane distance, and you think 1/4 D is more likely, you can simple devide the result by two since it enters linearly, so the distance is still about 40 microns!

Now if you calculate this for different edge angles (always edgeangle per side, so 5 deg corresponds to an included angle of 10 deg) with a highpoint-lowpoint distance of 1/2 D and a particle diameter of 40 microns:

phi=15 deg -> d= 110 microns
phi=10 deg -> d= 170 microns
phi=5 deg -> d= 345 microns

Those are some seriously large teeth and precisely the reason why I said that carbide size is hardly going to matter much any more at the really low grits.

Just for fun, even an 8000 grit waterstone (1 micron) will leave about 8 micron deep valleys between the teeth at 5 deg per side! Of course on a steel like S30V this is of course fatal. In S30V the carbides are about 5 microns on average, which means, each tooth is pretty much exactly the size of one carbide and it will have no support at all.

Hope this post wasn't too long.

 

[db]

HoB great info. I think the amount of pressure applied can and does change all of that though. I do agree the lower the angle the toothier an edge can be but I have a hard time believing it is very noticeable. It has been a long time since I played around with different angles and grits. Would a 4000 finish at 10 degrees be as toothy as a 2000 at 20 degrees? I’m going to have to do some low angle grinding I have to see an 8000 finish that is toothy.

 

[HoB]

Would a 4000 finish at 10 degrees be as toothy as a 2000 at 20 degrees? I’m going to have to do some low angle grinding I have to see an 8000 finish that is toothy.

Well, I don't know of the top of my head since the grit number is not linear and there is no particular function that connects grit # and particle size. But if you would compare 2 micron grit at 10 deg per side against 4 micron grit at 20 deg then, no they don't give the same finish. Particle shape and pressure and direction of the stroke all equal, the finish on the 4 micron grit at 20 deg will actually be finer than the 10 deg at 2 microns. The particle size enters proportionally, while the angle enters as the tan, which is very non-linear.

Yes, the pressure and the particle shape will play a big role. A very pointy particle will have a very large penetration at the same pressure than a rounded or flaky one (imagine the scales of a fish, they may be very large but only the thickness of the scale will determine how deep a cut it will leave). I bet that is the reason why the DMT 8000 EE gives according to Thom a much rougher finish than an 8000 grit waterstone, diamonds are very pointy and angular. But regardless of the actual highpoint-baseplane difference, at very low angles, the effect will be dramatic.

You also have to realize that the depth of the valleys between the teeth is not equal to the "width" of the edge. The row of teeth that form the edge may themselves still be very pointy (radius of curvature around 1 micron for example), but I think it is useless to be talking about an edge per se anymore because each sharp point may be separated many times its radius of curvature from the next sharp point. In other words, the teeth may be sharp (in the sense of a fine edge), but there will be HUGE gaps between the teeth. Well, to be more precise, the gaps will be very deep but not overly wide. Like a saw with very long teeth that have steep flanks, although, god only knows what kind of gaps you will tear into the edge when you have these really long teeth at low angles. I suspect you will tear half of them off, leaving bigger gaps than the theory would predict and the other half will will partially break off during the sharpening, which would reduce the valley depth substantially.

I have to see an 8000 finish that is toothy.

Well, even according to the theory the valleys are only 8 microns deep at 5 deg per side, which is pretty extreme. It is possible to see 8 microns with a 100x microscope, but it's getting pretty small especially since you are not looking at something flat but rather something that is slanted. Depth of field will be a major problem imaging that, but it might be possible.

 

[db]

if you would compare 2 micron grit at 10 deg per side against 4 micron grit at 20 deg then, no they don't give the same finish. Particle shape and pressure and direction of the stroke all equal, the finish on the 4 micron grit at 20 deg will actually be finer than the 10 deg at 2 microns. The particle size enters proportionally, while the angle enters as the tan, which is very non-linear.

Thanks that is much clearer than what I asked and was just what I was wondering. I'd assume those of us that like an edge with a certain amount of bite indeed need a few different stones if we sharpen different knives to different angles to get the edge effect we like. I also am guessing this is why so many people seem to get different results with the same stone/hone from one another. Back when I was trying to find an all purpose edge I really like I never really thought of finish and angle affecting each other. I did play around a little with scratch pattern and how it could effect how a knife cut. If you angle the scratch pattern you can notice a different resistance on a forward , pushing slice, and a backwards, drawing slice cut. However, what I ended up with for an edge had alot more to do with ease of sharpening and how I sharpen freehand, more so than any smallish performance difference in the edges.

 

[Dog of War]

The carbony effect you're seeing might well be the particle size and volume of the carbides that Larrin Thomas, Roman Landes, and Cliff Stamp have discussed. According to Larrin, AEB-L and 13C26 are similar to 52100 and Hitachi/YSS White Paper steel in terms of carbide size and volume as well as martensitic grain size and attainable hardness. Probably explains why me 13C26 Kershaws sharpen up so easily and don't do courtesy microchipping when the final edge (or microbevel) is below 30 degrees, too. Or in shorter sentences: Yeah, more fun for us like youse said!

From your many posts it seems you and I appreciate 13C26 for all the same reasons (I wonder if those who've been critical of Kershaw's current heat treat and use of this steel have tried it ... it certainly blew away my expectations.) When I did the rope cutting tests with the JYD2 I was amazed how the edge held up, not only was it essentially flawless when freshly sharpened, viewed under 40x magnification, but it seems the least prone to chipping of any steel I've used. In fact I like it so much, I've got an ENER-G on the way!

As I've said before, Thom, you really should be a professional writer, probably a humorist.