Diamond Matrix vs. Shapton or Chosera for EP?

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Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Wed Jul 31, 2019 8:30 pm

So, Radar, you basically do all your edge pro sharpening with diamond films? Ben Dale told me that his polishing tapes are a bit better than what their diamond matrix stones can do. Given that, if the costs are manageable, films seems like an attractive approach to the edge pro.

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Otaku19
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Otaku19 » Wed Jul 31, 2019 9:15 pm

I much prefer the stones because I just have to keep them flat versus swapping out the tapes. Just my preference and Grant's method is equally effective. I've watched a video from Cliff Stamp a while back that backs up what you are referencing about the burr. He likened it to bending a spoon back and forth until it became fatigued and broke. He called his method "plateau sharpening." I've also read some theories that say that a burr is wasted metal and that there is no advantage to drawing a burr at 120 grit versus waiting and drawing a burr at 1k. Michael Christy draws a burr on every stone and his numbers on cardboard cutting are quite impressive. I would actually like to know which method is better as far as how it effects edge retention. This has become quite an intriguing thread :-)
Last edited by Otaku19 on Wed Jul 31, 2019 9:16 pm, edited 1 time in total.

Radar53
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Radar53 » Wed Jul 31, 2019 9:16 pm

Delphonic wrote:
Wed Jul 31, 2019 8:22 pm
The whole idea of a burr is a bit odd. It seems predicated on the idea that you never know you’ve gone far enough until you know you’ve gone TOO far. Not that I have any work around for this apparently necessary evil.
Hi Del. That's a pretty fair summary. The real difficulty is knowing when you have actually sharpened to the edge-of-the-edge. If you don't get there then your edge is not as sharp as you could get it. The unfortunate thing is that you need to have Jedi Master skills to get to that point and not go past it. I certainly don't have those skills, but it seems there are sharpeners on this forum that do - very few I would guess.

For the rest of us mere mortals, the one known thing is that forming a burr is a result of getting to an apex. The trick is to make the burr as fine as possible & stop there, rather than grinding until it's a huge burr. Peter Nowlan is one of the professional sharpeners on this site and a scholar of getting knives sharp. Fortunately for us he likes tell us about what he finds and he would be probably the best teaching resource I have found.

He has recently changed from "not trying to form a burr" to "trying to form a very small burr" and you can find his commentary here http://sharpener-pete.blogspot.com/2019 ... iquie.html (You might also like to read as many of his blog posts as you can as they are gold nuggets.)

I have always formed as small a burr as possible, on every stone that I use in a progression. Removing said burrs, without ripping them off by using felt blocks etc, ie by using stones and strops, is another whole subject in itself.
Cheers Grant

Just because you're not paranoid doesn't mean they're not going to get you!!

Radar53
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Radar53 » Wed Jul 31, 2019 9:35 pm

Delphonic wrote:
Wed Jul 31, 2019 8:30 pm
So, Radar, you basically do all your edge pro sharpening with diamond films? Ben Dale told me that his polishing tapes are a bit better than what their diamond matrix stones can do. Given that, if the costs are manageable, films seems like an attractive approach to the edge pro.
Hi Del & Anthony as well. The short answer is "No!". As per one of my earlier posts, I generally use stones, because for doing a lot of work, they work out cheaper than using the 3M films. A single, cut down film (ie a 1" X 6") will generally last me about 3 knife sharpenings. Obviously if I'm making repairs or cutting a new bevel the lower grit work will take more of a toll, but as you get to the finer grits you are generally only polishing a bevel & edge that you have already created - so less wear on the films.

Also, and I think that Otaku has said this as well, use grinding media that is appropriate for the work in hand. I pretty much only use my diamond films on wear resistant & / or PM steels. Another really nice benefit of the films is that (apart from the 120 grit film) the PSA backing is the same thickness throughout. This means that once I have my setup organised the first time, I simply peel one film off my blank and stick the next one on. No faffing about adjusting for different stone thicknesses and the like to ensure that consistency of angle is absolutely maintained and yes I am a bit OCD :roll: :roll: .

Another thing I find is that grit-for-grit the films leave a slightly toothier edge. No problem here just something that I've noticed.
Cheers Grant

Just because you're not paranoid doesn't mean they're not going to get you!!

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Thu Aug 01, 2019 1:12 pm

The problem that the burr solves is knowing you’ve gone far enough in the metal removal. But of course you’ve gone a little bit too far to create the burr, in order to be sure you did not stop short. But without microscopic visual analysis, how else do you know? Bed Dale told me that he’s had very few customers over the years who can sharpen without using the “get-to-a-burr system.”

Of course the other matter to address is what the hell you do with the burr— itself a rolled edge if ever there was one!— once you’ve got it. That’s what I found interesting about the Australian guy’s article. Ripping the burr off is terrible, and different methods of more complex burr removal are appropriate with different steels. They refer to the burr as a necessary evil, if I recall correctly. Another upshot seems to be not overdoing it on the burr. More is not only not better, it’s worse! Maybe that argues for waiting to get to a burr until you gets to a higher grit than your first stone, as described above in the previous post. But then you have to make a guess about where the edge is at with the lower grade stones. It has to be “close enough” to a burr if you’re going to wait till a higher grit to go to a full burr and have this approach be viable and/or superior to raising a burr on the first stone.

Radar53
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Radar53 » Thu Aug 01, 2019 5:15 pm

Pete Nowlan covers off burr removal pretty extensively in his own blog and he also did an "Essentials" course for Knife Planet, so it's worth checking out. He sharpens probably 10,000+ knives a year and I really get a lot from writings.
Delphonic wrote:
Thu Aug 01, 2019 1:12 pm
Maybe that argues for waiting to get to a burr until you gets to a higher grit than your first stone, as described above in the previous post. But then you have to make a guess about where the edge is at with the lower grade stones. It has to be “close enough” to a burr if you’re going to wait till a higher grit to go to a full burr and have this approach be viable and/or superior to raising a burr on the first stone.
Many years ago I tried what you talk about above & called it "creeping up on the edge". It was an exercise in frustration, because as you indicate there is no way for us mortals to accurately know when the next stroke of the stone is going to actually get to the edge-of-the-edge. It was wasteful of my time and created a good bit of higher-grit stone wear/wastage.

For me cleaning up the bevel or edge is best done on the coarsest stone that I intend to use for any given sharpening progression & that will vary depending on if it's a repair, a new bevel, just a general refresh - a starting stone of anywhere between say 120grit to 2000grit. I raise the burr and get the edge to cleanly cutting phone book paper with that first stone whatever it is. The reason is because this becomes my foundation for the rest of the journey ie establish the edge and then simply refine it from there. So as above I establish a small burr & remove said burr on the first stone, right from the get-go & before I move on.

This means that I know I have the basic platform right and that the hard lifting has been done using the most appropriate stone for that work. Then each progressive stone is doing the work that it is best suited for and not trying to cover off heavier lifting better suited to a coarser stone. So I'm not wasting time trying to do the work of a 500grit stone with a 2000grit stone, which is really time consuming and frustrating. It also causes excessive wear to the higher grit stone that is trying do work for which it is not suited.

I have skimmed the book for now and it looks very interesting. I will check it out over the weekend more fully, so thank you for sharing. I note that he talks about edge leading & edge trailing burr removal. I use edge leading burr removal strokes almost exclusively and yes I know I am in a minority here, but I am very comfortable doing edge leading stuff.

All interesting stuff so thanks for one of the more informative threads on the EP side of things in a while.
Cheers Grant

Just because you're not paranoid doesn't mean they're not going to get you!!

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Thu Aug 01, 2019 7:07 pm

Grant— after you raise a burr with your initial grit stone, do you keep creating burrs with each subsequent stones? Unless you’re doing something like stropping, it seems to me the issue of “not knowing you’ve gone far enough” until you at least started to get a perceptible burr persists.

Radar53
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Radar53 » Thu Aug 01, 2019 9:12 pm

Hi Del, yes I do. But now that the edge is established, and in a tight progression, it generally only takes 3 maybe 4 strokes on each side. I can generally feel a burr up to about the 5k grit mark and above that I just assume that they're there and go through my removal process anyway, until I go onto stropping.

In terms of removing the burr on the EP, I use edge leading strokes, alternating sides for each stroke, getting progressively lighter each time. The second to last stroke on each side is just the weight of the stone and stone arm with no downward pressure and the last stroke on each side is very light with me supporting some / most of the weight of the stone & stone arm.

There's no fixed recipe here with any of this, as it's all dependent on the the level of final finish you are seeking and of course specifics of that particular stone & steel. It's one of those things where you just have to play around with it until you get the outcome you're looking for.
Cheers Grant

Just because you're not paranoid doesn't mean they're not going to get you!!

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Thu Aug 01, 2019 9:55 pm

Thanks. Lol. Just as I feared. Sometimes I even wonder if I wouldn’t have been better off getting free hand stones. Which is funny. Because I’ve not even gotten good at using my edge pro!

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Thu Aug 01, 2019 9:56 pm

My hunch is that my application of pressure or not so much pressure has been a variable I’ve under appreciated. After reading some of the Peter Nowlan stuff that seemed especially likely.

Radar53
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Radar53 » Thu Aug 01, 2019 10:42 pm

Delphonic wrote:
Thu Aug 01, 2019 9:55 pm
Thanks. Lol. Just as I feared. Sometimes I even wonder if I wouldn’t have been better off getting free hand stones. Which is funny. Because I’ve not even gotten good at using my edge pro!
Del, I added freehand sharpening to my skills base about two & a half years ago now. I made a relatively easy transition and for some time now my edges have been pretty good. Nice consistent bevels, not too much wobble & nicely sharp. I really enjoy the added dimensions as well - eg the "zen" factor. But here's the thing, a lot of that came about because I already knew & understood the science & practice of sharpening. Did have to learn & practice new stuff & techniques as well of course.

There's no substitute for time & practice whether it's the EdgePro etc or freehand. Having said that my freehand edges are not near as good as the edges I can get off an EdgePro, but they will continue to improve with ongoing practice. Long story short you have to be in the game to progress and like most things, there's a period of apprenticeship if you like. Either way you'll have to go through that and it can be frustrating at times!!

Either EP or freehand you can shortcut the process by asking questions through this forum and other members will help you not to make the same mistakes most of us make.
Cheers Grant

Just because you're not paranoid doesn't mean they're not going to get you!!

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Sat Aug 03, 2019 6:41 pm

These are passages I copied to my own notes from the knifegrinder’s website in Australia. Credit and authorship for each statement goes to Dr. Vladim Kraichuk

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Sat Aug 03, 2019 6:42 pm

Kraichuk’s statements

“A sharp knife that fails early usually is the result of a wire edge that hasn't been properly removed.

“A good sharpener knows how to apex and deburr the edge; an expert sharpener knows how to clean the apex of the weak wire edge not rounding it.” [which requires 1 micron diamonds or CBN]

“Edge-leading sharpening produces a smaller burr and is preferred on the coarse, medium and fine grits to as fine as JIS 8000; honing on finer grits however is better done edge-trailing.”

“We set 2 honing paper or felt wheels - one at the exact edge angle*, it will hone away the bulk of the burr with a 3-6 micron honing substrate; and the second at 0.4 - 2 degree higher angle depending on the steel as specified above (e.g. a 15 dps edge will be honed at 15.4 - 17 dps), it will hone away the burr root and has 1-micron honing substrate. It took us a lot of sharpness tests in trial and error to conclude that the 1-micron abrasive de-roots the burr best of all.”

“HIGH-END VERSUS MAINSTREAM KNIVES
Facts debunk the myth that super-steels hold super-sharp edge. Facts tell us that the initial blunting rate is relatively rapid regardless of steel. Though high-end wear-resistant edges win in the long run, they lose their initial keenness almost at the same rate as a mainstream knife. High-end knives win over mainstream as stayers, but they are equal sprinters. High-end knives and mainstream knives lose the initial keenness of the 0.05-0.2 micron apex similarly easy, but past this point the similarity ends.”

“There is a simple explanation to this phenomenon. What makes a knife steel high-end is the large volume of wear-resistant carbides, and these carbides are 10s times the size of the razor edge. For example, vanadium carbides sitting in the steel matrix average 20 microns in size in conventional tool steels (e.g. D2 steel), and 1 to 5 microns in CPM steels, while the razor apex width is under 0.1 micron. The question is if we really can polish those wear-resistant carbides as fine as to the 0.1 micron razor edge when we sharpen them with diamonds and CBN?”

“The above SEM images [omitted] clearly show that when we sharpen a tool steel or high-end blade using anything but diamonds and CBN, it is not possible to polish those wear resistant carbides sharp, as we'll only be abrading the steel matrix around them, burnishing it to the edge, and eventually getting a very sharp steel edge that won't last long. As we start cutting with such an edge, the ultra- sharp steel apex quickly turns into a relatively dull edge made of big unpolished carbides.”

“Even if you do not own a BESS sharpness tester, you can do a similar test for wire edge by push- cutting a stretched fluorocarbon fishing line, and checking with the loop if the very edge has got a micro-dent in the point of the cut – wire edge will dent, while the cleanly deburred apex will not. The fluorocarbon fishing line must be 7 LB 0.21 mm or near that.”

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Sat Aug 03, 2019 6:57 pm

Perhaps the most important of all the excerpts above is his claim that you must use diamond or CBN to actually sculpt/cut the hardest carbides in the best knife steels. The quality of an edge created by softer abrasives is fundamentally different. With non-diamond/CBN, you can only abrade/sculpt the softer components of the steel, but are left with an embedded patchwork of ragged, uncut, jumbo-sized carbides that are far to big to be part of an ideal apex. Eg, 20 µm versus 1 µm.

This seems like a sound identification of bottleneck in sharpening methodologies. Is it the crucial bottleneck for many? That I don’t know.

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Sat Aug 03, 2019 7:03 pm

On a bit more consideration, this claim seems like something of a bombshell. With the exception of stopping compounds, and niche diamond abrasives from, eg, Atoma or Edge Pro Diamond Matrix stones, I don’t suppose that most or any of the offerings from the obvious stone-makers would meet the hardness test required to cut/sculpt the hardest carbides.

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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Radar53 » Sat Aug 03, 2019 9:24 pm

Hi Del,

I'm only partway through reading the pdf book and I have to say there is some really good stuff there. Stuff that I have been trying to hunt down for ages, that I think would promote some really interesting discussions on the wider forum here; ie each as separate threads under the Sharpening Advice section of the main forum . The three areas that I see are potentially carbide tear-out, burr removal and stropping. (Haven't read enough about the stropping areas as yet?)

Would you be happy / comfortable to undertake that?? Happy to assist in any way I can, if that's of any help.
Cheers Grant

Just because you're not paranoid doesn't mean they're not going to get you!!

Delphonic
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Sat Aug 03, 2019 10:00 pm

Yes, I only put it here because of the way this thread unfolded. But this is surely not EP specific info. These are broad metallurgical issues of wide interest. Not sure how best to transplant the elements of the thread.

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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Delphonic » Sat Aug 03, 2019 10:34 pm

Ok. I transplanted the content to the sharpening advice forum.

I didn’t start three separate threads, though carbide tear out and deburring certainly could warrant their own threads.

Radar53
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Radar53 » Sun Aug 04, 2019 2:05 pm

Great stuff. Full on work day for me today so will catch up with it all later.
Cheers Grant

Just because you're not paranoid doesn't mean they're not going to get you!!

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Otaku19
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Re: Diamond Matrix vs. Shapton or Chosera for EP?

Post by Otaku19 » Sun Aug 18, 2019 7:19 am

My apologies for the delay in my post. I've been moving and getting my internet swapped over to the new address. Extremely informative information by both of you!! This is a short video where Cliff Stamp elaborates on his plateau sharpening and his thoughts on burr formation: https://www.youtube.com/watch?v=OPGGo3W15HQ

Just in case you miss the description, here is what Cliff elaborates on:
"This is a very short and simple video which shows a few key points of sharpening :

1) Destress the edge by grinding off all weakened metal by cutting into the stone

2) Grind the apex bevel until it stops reflecting light, this is just getting the edge to the right shape. It does not take an overt amount of attention or focus.

3) Finish the apex to the desired grit paying attention to minimize the burr.

To simplify the process the finishing grit was kept at the shaping grit (200 SiC) which leaves an edge with a very aggressive slicing finish but also can easily shave, slice newsprint, and is very close to a true push cut (90 degrees in all three planes) on the newsprint.

In this case when finishing the apex the angle was raised to 15 dps (the bevel was shaped at 10 dps). The increase in angle is just to add durability to the edge as this is used very roughly in the kitchen by friends and family, i.e. it will scrape out pots and the like, it isn't restricted to just cutting.

In order to get to a true 90 push cut on the newsprint all that has to be done is be a little more careful on the final finishing which means :

1) Clean the stone

2) Reduce force to the absolute minimum (5-10 grams)

3) Go very slow with short travel on the stone.

4) Change the presentation angle of the knife to the stone to make the scratch patterns cross over.

To maximize the cutting ability the 15 dps bevel would also be minimized to a true micro-bevel by back sharpening at 10 dps.


As noted in the video, a few other details :

1) The benchstone used is extremely cheap and thus it cuts slow, loads easily and is conditioned with a 200 grit SiC waterstone to give it some fast cutting swarf. Without this step the time would be increased ten fold on the benchstone it cuts that slowly.

2) Grinding to form a significant burr stresses the edge heavily and leads to premature failure of the knife edge, especially if it is done with very coarse stones. The edge should only be shaped until it forms an apex, no further. The point of sharpening is to minimize a burr, the best way to do that is not form a large one in the first place.

This is the same process used on any style of knife, machete or axe, the only thing that changes are the grits used based on what is desired and the angles used in the shaping stage. If the knife is used more for push cutting then higher cutting ability and edge retention will be produced with a finer polish and as less durability is required the edge can be set to a lower angle.

This technique was developed to fill the goal of being able to sharpen knives for friends in two minutes or less even though they may come very dull and damaged. By starting with the right abrasive for the shaping stage even very dull knives can be brought back to life very quickly. The extra step to get a true push cut finish will take an extra 30-60 seconds on the stone using the above four techniques."

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