So how much better is a higher grade stainless?

[thombrogan]

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.

Can't it be both? BTW, I used my 240AS to open a bottle ala Mrs. Gunmike1 and the edge chipped! Now unlike when that's happened with other steels, the edge didn't roll and the chipping was just larger than microchipping. Guess it's time to wash off the oil and break out the D8F, Glasstones, and lapping films... D'oh! Always gotta push!

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.

Actually, there are folks using various grades of YSS Shirogami wondering why we're so gaa-gaa over such a pollutant-enriched steel.

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!

Oh gnomes! We're looking at a fullness of dullness! It's not acute; it's an ugly!

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!!!

Aaaauggghh! Just when I try to forego polishing cloth and lapping film, it keeps drawing me back in!

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.

That's a generous 8000 (Kitayama?) and the results are scaring me. My 8,000 hones are 3 micron (DMT and Norton), 1.82 micron (Shapton), and unknown (Matsunaga King). Stupid extra justification for microbevels... grumble grumble grumble.

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!

The steel is very malleable in terms of uses. You can fly in a ton of folks with more knife experience than me (or walk them in; they're everywhere!) and not a single word said is going to make the steel duller or less tough. I'm at the point where I like every knife and steel I see and use, but it's very easy to use and like 13C26 the way it's cranked out of Tualatin, OR. Their other knives in other steels are great, too (knifeknuts aren't supposed to like the 440A Leek and yet it r0xx0rz in my book and UnknownVT's, too), so it isn't until resharpening that the fun of 13C26 is shown (which takes a while because it doesn't microchip at the sub-40 angles nor crack all to heck when the edge rolls). Thanks for the kind words, Dog of War. Maybe we should co-author some knife books.

 

[HoB]

Sorry, Thom, you are right of course, I thought of the Shapton standart and meant to say 8000=2 microns. But I used 1 micron for my calculations.

 

[Dog of War]

The steel is very malleable in terms of uses. You can fly in a ton of folks with more knife experience than me (or walk them in; they're everywhere!) and not a single word said is going to make the steel duller or less tough. I'm at the point where I like every knife and steel I see and use, but it's very easy to use and like 13C26 the way it's cranked out of Tualatin, OR. Their other knives in other steels are great, too (knifeknuts aren't supposed to like the 440A Leek and yet it r0xx0rz in my book and UnknownVT's, too), so it isn't until resharpening that the fun of 13C26 is shown (which takes a while because it doesn't microchip at the sub-40 angles nor crack all to heck when the edge rolls).

Well said. First thing that made me realize this steel was something special was reprofiling my JYD2, it was difficult to detect any burr at all. Then the way the edge looked at 40x after a few swipes on the crocksticks. Pretty much all upside surprises since.

Thanks for the kind words, Dog of War. Maybe we should co-author some knife books.

Likewise. And maybe I can get Phil to ghostwrite my contributions to these books.

 

[thombrogan]

HoB,

Please accept my apology for nitpicking. Was actually hoping you had a source on 1 micron/8K waterstones.

DoW,

You might be found out when your portion mentions how taxing it is to grind CPM10V, but how worth it it is when skinning elk.

 

[gunmike1]

Can't it be both? BTW, I used my 240AS to open a bottle ala Mrs. Gunmike1 and the edge chipped! Now unlike when that's happened with other steels, the edge didn't roll and the chipping was just larger than microchipping. Guess it's time to wash off the oil and break out the D8F, Glasstones, and lapping films... D'oh! Always gotta push!

My wife is very proficient at decapitating Gatorade bottles with ultra thin edges, I guess. I did notice some small chips when I sharpened it, but nothing major, or at least nothing more than I notice from it crashing into the cutting board because it doesn't seem to notice the food it is cutting through. I think most of the dulling on my Takeda is from crashing into the cutting board as it sailed through food, it just cuts way better than the crap kitchen knives that I am used to so I use too much pressure. Anyway, as far as bottles, I guess the cast helped my wife to keep everything dead straight when lopping off bottle tops. I haven't tried it myself with the Takeda, just my pocket knives, which do it without damage, but at much more robust profiles. I would guess my sloppy technique would lead to big chips using the Takeda, so I'll leave the bottle decapitations with the Takeda to Mrs. Gunmike.

Mike

 

[thombrogan]

I was using a plastic cutting board for a while and got lil chips on my Takeda. Switched to wood and the problem went away (but now I can recreate and amplify it with bottles! Oh joy!). Are you using a polypropelene slab of edge-doom? If so, a more thicker edge (and it's insane to call a thinned out 8 degree edge with 15 degree microbevel thicker - we're gone, d00d; gone!), a more traditional techinique (more of a downward slice than an actual chop), or closed-grain wooden cutting board may help.

Apologies to DoW if I've scared you away.

 

[Dog of War]

Apologies to DoW if I've scared you away.

Think you lost me there ... but if you mean all this violence you and gunmike's wife enjoy inflicting on poor, helpless plastic bottles, don't worry, I'm kinda into gratuitous violence myself.

BTW, been thinking about this discussion of the effect of edge angle when sharpening with coarse stones, and it makes sense to me that you could get a less coarse edge if sharpening at a more acute angle. For one thing less lateral force is being applied right at the edge apex at lower sharpening angles; plus, other things being equal, you're working a wider bevel so the force is being distributed over a greater area. Yet another thing to add to my to-do list, I guess.

 

[the possum]

At this point I feel it's too late for me to add much, because I don't have time to type everything, but I have been following & enjoying this thread for a few days. Thanks guys.

 

[hardheart]

HoB, about your work on creating microteeth, I was wondering what effect moving the blade along it's edge has on this. It seems that as we sweep from ricasso to tip, and at slightly different starting positions, the steel and abrasive meet in a way where the teeth would be removed by the lateral motion. These teeth would also be terribly thin, wouldn't they?

 

[gunmike1]

I was using a plastic cutting board for a while and got lil chips on my Takeda. Switched to wood and the problem went away (but now I can recreate and amplify it with bottles! Oh joy!). Are you using a polypropelene slab of edge-doom? If so, a more thicker edge (and it's insane to call a thinned out 8 degree edge with 15 degree microbevel thicker - we're gone, d00d; gone!), a more traditional techinique (more of a downward slice than an actual chop), or closed-grain wooden cutting board may help.

Apologies to DoW if I've scared you away.

Thanks for the tip on the cutting board, I will go get a good wood one this weekend to replace my poly chipmaster cutting board. And yes, we are very far gone, but I can't corrupt my Takeda with such hideous things as a 15 degree microbevel, if it came from the factory with a 9 degree bevel then I can't rightly exceed that, and it seems to hold the 8 degree edge pretty good so far. If it chips badly I MAY go to a horrifically fat 10 degree microbevel and hang my head in shame, but only if I absolutely have to.

Mike

 

[thombrogan]

:barf: How devestating! But still... ...even the crafter of our mantra uses a microbevel on some of his cleavers made with Aogami Super. That's the problem with hero worship: get your boo-boo snipper to snip with a sub-5 degrees edge and find out your mentor adds a microbevel with a Kitayama 8/12 stone. I think Novak's "Prince of Darkness" mentions a publicly-constitutionalist conservative who secret hones his jackknives with the attachment on a can opener.

Glad to read you're here, the possum, and that you're still here, Dog of War!

The possum, do you sharpen that thin-bladed semi-bainitic vermin-snipper with a Gerber 150 grit AO puck or do you use something else?

 

[the possum]

It's not a puck; it's a cheap double sided stone about 6" long & 2" wide. Actually I have 3 of 'em, picked up from flea markets or somesuch over the years. One was still in the box with Chinese writing, for $3. One side is around 80 or 90 grit, and the fine side D) is something like 120-150 or so. I'm pretty sure they're AO, but might be silicon carbide. Primary sharpening is done around 10 degrees or so, and convexes from blending with the main grind to around 18 degrees per side at the very edge. (may range from 14 degrees all the way up to 25 degrees depending on my anticipated scenarios, or how lazy I'm feeling.)

 

[gunmike1]

:barf: How devestating! But still... ...even the crafter of our mantra uses a microbevel on some of his cleavers made with Aogami Super. That's the problem with hero worship: get your boo-boo snipper to snip with a sub-5 degrees edge and find out your mentor adds a microbevel with a Kitayama 8/12 stone. I think Novak's "Prince of Darkness" mentions a publicly-constitutionalist conservative who secret hones his jackknives with the attachment on a can opener.

I know our hero mentioned the microbevel with the Kitayama, which almost made me faint after spending about 2 hours sharpening my knife without one, but that means I need a 16K Glasstone to add a microbevel and still meet his standards (only ultrafine stones for a microbevel after forming the main bevel), or at least that might be my nutty logic to justify buying that stone. 1 micron lapping film does the same job as that stone, but I think the stone will work better for the ham fisted like me for edge into sharpening than the lapping films. Anyway, at least at that point you would probably need high magification to even see the microbevel. In the meanwhile I will hold out hope that my 8 degree edges can hold together so I don't have to use a microbevel.

Mike

 

[Broos]

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

I need to do one with the DMT XXC and give it a shot.

I'm still trying to digest the sharp/coarseness stuff. good stuff. I'm trying to visualize two corrugated planes meeting at an edge.

 

[HoB]

HoB, about your work on creating microteeth, I was wondering what effect moving the blade along it's edge has on this. It seems that as we sweep from ricasso to tip, and at slightly different starting positions, the steel and abrasive meet in a way where the teeth would be removed by the lateral motion. These teeth would also be terribly thin, wouldn't they?

Yes, they would be very thin at low angles. And, yes, I would suspect that a few swipes at an angle less than 90 deg with respect to the edge would remove the teeth. But on the other hand, if you hone at an angle less than 90 deg with respect to the edge, it is as if you would reduce the edge angle further and the valleys between the teeth would be even deep, but angled with respect to the edge.

 

[fdd19]

Well i just got my Entrek Merc which comes in 440C stainless and it is the sharpest knife ive ever had it easily blew away my USMC ka-bar which was the knife i measured sharpness against its insane id love to know how what geometry and grit they sharpen it at so i can replicate it with my edgepro (what tool would i use to give me the angle, a mark wont give me a numerical value, im thinking of an actual tool like a protractor, though i doubt that would work).

 

[Dog of War]

Well i just got my Entrek Merc which comes in 440C stainless and it is the sharpest knife ive ever had it easily blew away my USMC ka-bar which was the knife i measured sharpness against its insane id love to know how what geometry and grit they sharpen it at so i can replicate it with my edgepro (what tool would i use to give me the angle, a mark wont give me a numerical value, im thinking of an actual tool like a protractor, though i doubt that would work).

If you have a good dial or digital caliper, you can calculate the edge angle pretty closely by measuring the width of the edge bevel:

and then measuring the thickness of the bevel right at the shoulder, i.e. at the very back of the bevel, where it meets the rest of the blade (sorry, no pic.)

Let's say the edge bevel measures .040" wide, and the thickness of the shoulder is .020". The math you need to do is first divide the shoulder thickness by 2, giving you .010, then divide that by the bevel width --

(.020/2)/.040 = 0.25

Then using a calculator (or spreadsheet even) find the inverse sin of 0.25, which is about 14.48; this is the angle of the edge bevel on that side.

Note that many times the bevel angle will vary from side-to-side, and/or along the length of the edge, so it's a good idea to measure at a couple different points, and measure the bevel on each side. Personally I'd then set the EdgePro to sharpen at the lowest measured angle, or a little less. Based on quality 440C blades I've had -- and it really can take a nice edge when the heat treat is good -- there's no need to run the edge at greater than 15 degrees/side, and 12 degrees/side (my favorite all-'round sharpening angle) should work just fine and likely noticeably improve cutting ability compared to most factory edges.

Hope that helps ... and if you don't have a calculator, just post your measurements and I or someone else here will punch in the numbers for you.

 

[Larrin]

This was/is a very interesting thread. Thanks guys.