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TOPIC: A theory of how the WE diamond pastes work

Re: A theory of how the WE diamond pastes work 2 years 4 months ago #2566

  • mark76
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jendeindustries wrote:
An excellent thread, my friends!!! :woohoo:

Welcome back, Tom! Work even continues when the master is not looking B).
Overall, I'm beginning to conclude that what I thought before has become an even stronger argument - and that is to progress as far as you can with stones and then use the pastes/sprays to "polish the grooves" the last stone's scratches rather than to attempt to establish a "true" grit edge with them.

I think you are largely right with your "I told you so" :cheer:. However, I’ve got two questions/reservations.

First, the burnishing/polishing occurred only (at least visibly) with the Wicked Edge pastes. My gut feeling says (and maybe Clay’s pictures show) that this is not the case for Ken’s and HA’s particles in spray. If these spray are diamond or CBN particles in water or a similar liquid, I don´t think they burnish well. (I experimented with water on a leather strop, but it didn’t make the leather the slightest bit more sticky.) Clay’s pictures show that these particles do cause scratches and abrade.

My other big question is what burnishing the edge, or polishing the grooves, does to the edge of the edge. You wrote that when we polish the grooves after, say, the 1000 grit or 1600 grit stones, we get a toothy, yet clean edge. But couldn’t it be that the burnishing also removes (or at least polishes) the teeth at the edge of the edge? After all, the edge of the edge is part of the edge, isn’t it?

This is also why I asked Clay whether he had done any cutting tests. If the burnishing removes/polishes the teeth, it should result in a very good edge for push cutting. If it doesn’t, we would indeed have a more toothy edge that is more suitable for slicing.
Last Edit: 2 years 4 months ago by mark76.
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Re: A theory of how the WE diamond pastes work 2 years 4 months ago #2567

  • wickededge
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mark76 wrote:
jendeindustries wrote:
An excellent thread, my friends!!! :woohoo:

Welcome back, Tom! Work even continues when the master is not looking B).
Overall, I'm beginning to conclude that what I thought before has become an even stronger argument - and that is to progress as far as you can with stones and then use the pastes/sprays to "polish the grooves" the last stone's scratches rather than to attempt to establish a "true" grit edge with them.

I think you are largely right with your "I told you so" :cheer:. However, I’ve got two questions/reservations.

First, the burnishing/polishing occurred only (at least visibly) with the Wicked Edge pastes. My gut feeling says (and maybe Clay’s pictures show) that this is not the case for Ken’s and HA’s particles in spray. If these spray are diamond or CBN particles in water or a similar liquid, I don´t think they burnish well. (I experimented with water on a leather strop, but it didn’t make the leather the slightest bit more sticky.) Clay’s pictures show that these particles do cause scratches and abrade.

My other big question is what burnishing the edge, or polishing the grooves, does to the edge of the edge. You wrote that when we polish the grooves after, say, the 1000 grit or 1600 grit stones, we get a toothy, yet clean edge. But couldn’t it be that the burnishing also removes (or at least polishes) the teeth at the edge of the edge? After all, the edge of the edge is part of the edge, isn’t it?

This is also why I asked Clay whether he had done any cutting tests. If the burnishing removes/polishes the teeth, it should result in a very good edge for push cutting. If it doesn’t, we would indeed have a more toothy edge that is more suitable for slicing.

My everyday experience with knives heavily stropped with the different compounds is about what you'd expect: the very edge also gets super polished and with thicker blades and/or wider angles loses effectiveness for slice cutting. So far we've just been trying to look at abrasion patterns of the various media, next week I'll start imaging the actual edge to examine the effects of the various particles.

*As a side note, one think I like to do with a lot of my knives is t thin and polish the shoulders of the blade and then add a slightly toothy micro-bevel a few degrees wider.
--Clay Allison
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Re: A theory of how the WE diamond pastes work 2 years 4 months ago #2568

  • BassLakeDan
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From a previous post of mine.. "
John D. Verhoeven. Emeritus Professor. Department of Materials Science and Engineering. Iowa State University states two important frames of reference for his definition of a sharp edge in any discussion of knife sharpening systems....(edit for brevity..) he mentions his set of “standards of comparing blades sharpened (in his study)” to the following metrics: 1.) edge width 2.) straightness along the edge 3.) smoothness of the face surface. "


From Mark76 ..." My other big question is what burnishing the edge, or polishing the grooves, does to the edge of the edge. You wrote that when we polish the grooves after, say, the 1000 grit or 1600 grit stones, we get a toothy, yet clean edge. But couldn’t it be that the burnishing also removes (or at least polishes) the teeth at the edge of the edge? After all, the edge of the edge is part of the edge, isn’t it?"

From Clay... " So far we've just been trying to look at abrasion patterns of the various media, next week I'll start imaging the actual edge to examine the effects of the various particles."

Great news! I have been waiting for this discussion to migrate from the 'sides' to the 'end' of the edge' Notice that the good professor lists 'edge width' then 'straightness of that edge' then smoothness or burnish or polish or call it want you will as the last factor.. I assume that he knew of what he speaks. For very critical blade use the edge width is probably the most important factor in true sharpness. It is well known that the sharpest of surgical scalpels (made from obsidian) are in some cases *one* molecule wide !

So it will be great to see your photographs and measurement of width and how you achieve the narrowest widths with the WEPS.
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Re: A theory of how the WE diamond pastes work 2 years 4 months ago #2572

  • jendeindustries
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mark76 wrote:
First, the burnishing/polishing occurred only (at least visibly) with the Wicked Edge pastes. My gut feeling says (and maybe Clay’s pictures show) that this is not the case for Ken’s and HA’s particles in spray. If these spray are diamond or CBN particles in water or a similar liquid, I don´t think they burnish well. (I experimented with water on a leather strop, but it didn’t make the leather the slightest bit more sticky.) Clay’s pictures show that these particles do cause scratches and abrade.

There was definite proof that HA and Ken Schwartz sprays cut more than the pastes - Clay's adding the 1 micron diamond spray to the 1 micron paste showed how much more action the strop had and how uniform the resulting scratches were. This is directly related to the concentration of the abrasive particles, and not so much as to the type of medium they are suspended in/on (although the suspending mediums can influence overall effects - but that's not a factor in this case).
mark76 wrote:
My other big question is what burnishing the edge, or polishing the grooves, does to the edge of the edge. You wrote that when we polish the grooves after, say, the 1000 grit or 1600 grit stones, we get a toothy, yet clean edge. But couldn’t it be that the burnishing also removes (or at least polishes) the teeth at the edge of the edge? After all, the edge of the edge is part of the edge, isn’t it?

Let's limit this to the 1K diamond -> WEPS Paste argument first. For the most part, the depth of the 1K scratches combined with the lesser concentration of abrasive will polish the grooves, leaving the 1K scratches very clean, and what is essentially a polished 1K serration at the edge of the edge. To some degree, there will be abrasion/scratches at at the edge of the edge from the paste, but it won't necessarily reflect a "true" Paste grit edge. I'll get to this more in the next section.

As we have seen, coming off the ceramics to the pasts is much easier leap because the depth of the diamond scratches has been reduced by the ceramics, paving the way, so to speak, for the less intrusive pastes.

Overall, I think abrasive concentration is the most obvious influencing factor.
mark76 wrote:
This is also why I asked Clay whether he had done any cutting tests. If the burnishing removes/polishes the teeth, it should result in a very good edge for push cutting. If it doesn’t, we would indeed have a more toothy edge that is more suitable for slicing.

The polishing of the grooves allows for a smoother "feeling" cut, even though the edge is rather toothy. If I took a WEPS 200 Diamond edge and stropped it with the 3.5 micron paste, it would cut much more smoothly than just the 200 diamond edge. It would still be ripping, but there would be no burr or hanging metal pieces to catch the paper as it is test cut. With there being some abrasion from the 3.5 at the edge of the edge, you could push cut. However, this doesn't feel even remotely the same as taking a "true" 3.5 micron edge.
BassLakeDan wrote:
Great news! I have been waiting for this discussion to migrate from the 'sides' to the 'end' of the edge' Notice that the good professor lists 'edge width' then 'straightness of that edge' then smoothness or burnish or polish or call it want you will as the last factor.. I assume that he knew of what he speaks. For very critical blade use the edge width is probably the most important factor in true sharpness. It is well known that the sharpest of surgical scalpels (made from obsidian) are in some cases *one* molecule wide !

To continue with the polishing of the grooves effect and the "true" edge, we must look at edge thickness. The general rule is that as you get more refined, the edge becomes thinner. This is not always the case, as we can now discuss.

The aim of sharpening is to reduce the width at the tip of a triangle (the edge of the edge) to approach 0 width. Lets say we use a 16 micron diamond plate. In theory, the thinnest the width of the edge can be is ~16 microns wide. This is because the scratches in the bevel will theoretically be 16 microns deep, and if the edge of the edge is thinner than 16 microns, the abrasive will cut through to the other side. This is what causes the serrated-like edges at coarser grit stones.

Following this line of thinking, if you scratch the depth of each grit, then a 2 micron stone (8K) will create an edge width that is 2 microns wide. This is regardless of the edge geometry. If we listen to Prof. Verhoeven, the optimal thickness of an edge is about 2 microns wide (IIRC), which happens to be 8K. Anything past that, and is argued that the edge becomes less stable, which I agree with.

For a "true" finish, you have to establish those corresponding scratch depths on the bevel, thus creating the complimentary edge width. So, a true .25 micron edge is theoretically .25 microns wide at the edge of the edge.

This is a different approach to the polishing of the grooves. Let's divide this up to two things - the larger scratches are the "host" scratches, and the smaller scratches that polish are the "guest" scratches. If the "host" scratches are 16 microns deep, then the edge width should theoretically be 16 microns wide, with a serrated edge. When you add the "guest" scratches, let's say .25 micron for a major difference, they will get into the peaks and valleys of the serrations and scratches, making them smoother, and taking away some of the width of the edge of the edge by adding 64 tiny scratches (16 divided by .25) within each 16 micron scratch, but not making the edge .25 microns wide.

Both approaches have advantages and disadvantages - the "true" edges have the advantage of being able to slice/push cut more easily, although they become more fragile and more prone to rolling at the finer grits. The polished grooves leave an edge much thicker and therefore more durable, but at higher grits, there is instability caused by the "host" scratches which leads to an edge chipping out.

The fun in this game is knowing when and where to employ both methods. As I've stated earlier, I generally sharpen to 1 micron, then polish the grooves with remaining finer grits. However, if you are sharpening a knife not worthy of such refinement, then a 8 micron wide edge with a 1 micron polishing of the grooves will serve the owner well.
Tom Blodgett
Jende Industries, LLC

My Blog: jendeindustries.wordpress.com
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Re: A theory of how the WE diamond pastes work 2 years 4 months ago #2595

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Thanks a lot, Tom! Of course stones work like that! I should have made that up myself, but somehow I didn’t. (Which reminds me of a quote of my old professor, who said that the best articles are the ones that seem so simple you wonder why they were written.)

With your explanation of host and guest scratches, I think I can also make a bit more sense of some stropping spray progressions I read about on your blog. (But only a bit :-).) For example, you stropped your Spyderco Military with 0.25 micron spray and then with 0.05 micron spray. It seems the difference between 0.25 and 0.05 (factor 5) is too much to be able to wipe out the 0.25 scratches. Did you try to create 0.05 micron guest scratches on top of 0.25 micron host scratches?

If so, I understand that makes the edge sharper. However, wouldn’t the edge get even sharper if you did try to wipe out some of the 0.25 micron scratches, for example with 0.125 micron spray, then 1 and then 0.05 micron spray? Or do things work differently in the submicron rabbit hole?
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Re: A theory of how the WE diamond pastes work 2 years 4 months ago #2596

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The biggest challenge is examining the effects of those finer grits because our imaging doesn't get that fine. If we can get to >1000x we might be able to do a little better. If we're trying to get below .1 microns, then we're going to need access to much better imagining.... I'll post some pics a little later this morning of the edge with a variety of grits.
mark76 wrote:
Thanks a lot, Tom! Of course stones work like that! I should have made that up myself, but somehow I didn’t. (Which reminds me of a quote of my old professor, who said that the best articles are the ones that seem so simple you wonder why they were written.)

With your explanation of host and guest scratches, I think I can also make a bit more sense of some stropping spray progressions I read about on your blog. (But only a bit :-).) For example, you stropped your Spyderco Military with 0.25 micron spray and then with 0.05 micron spray. It seems the difference between 0.25 and 0.05 (factor 5) is too much to be able to wipe out the 0.25 scratches. Did you try to create 0.05 micron guest scratches on top of 0.25 micron host scratches?

If so, I understand that makes the edge sharper. However, wouldn’t the edge get even sharper if you did try to wipe out some of the 0.25 micron scratches, for example with 0.125 micron spray, then 1 and then 0.05 micron spray? Or do things work differently in the submicron rabbit hole?
--Clay Allison
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