Ken Schwartz

[Ken Schwartz]

Leo, looking forward to a chat especially about nanocloth strops!

Razor edge knives, I am just coming out with diamond lapping film over glass for the WE – more durable and an abrasive that will cut through more abrasion resista’nt steels – FYI. Let me know if you want more details – films going from 165 microns down to 0.1 microns. Lets chat and consider the alternatives I have available.

The nanocloth will also easily span the 1 micron or coarser range too.

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Ken

[Ken Schwartz]

Well it is a bit insane – but I say that in a good way! And of course the 0.025 micron is twice as fine! Sharpening insanity is a specialty around here.

I know Clay is a very busy guy, but he has some nanocloth for the WE and is going to do some testing with compounds as fine as the 0.025 and as coarse as he wants to go (I have CBN up to 80 microns 🙂 , so I’m anxious to know how this project works out. If anything, I’m becoming more impressed with how much difference it is making at coarser grits. Finer grits – well it’s a no brainer at this point 🙂

Clay is working on an order but if you just can’t wait, just send me a message and I’ll get you going in the mean time.

I’m also going to go to BLADE in Atlanta so hopefully I’ll see some of you guys at the show in the WE booth!

Leo, the nanocloth itself has as close to no effect at all – so when you put the compound on it the effect is a PURE compound effect – no effect from the nanocloth so no scratches from the substrate like you see with balsa or leather, with the exception to date being the kangaroo leather. At this point the race is between the nanocloth and the ‘roo – both (IMO) giving exceptionl results.

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Ken

[Ken Schwartz]

In the first video I demonstrated the difference between a synthetic stone finish and a natural stone finish. To those that closely observed the finish some coarser scratches were observable. Some have mistaken these scratches as being from the Hakka Tomae. I would remind you that this is not a coarse stone but rather a polishing stone that neither can remove such coarse scratches nor cause them.

So I went back, going back as coarse as a 400 grit stone up to a 2000 grit stone to remove the majority of these scratches and redid the finish with the Hakka Tomae once again, this time more fully demonstrating the capabilities of the stone itself.

In this video I finish the final stages to demonstrate the Hakka finish without the distracting coarser synthetic stone finishes.

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Ken

[Ken Schwartz]

THe reason I posted this video and image is because there have been questions asking about the sort of finish that natural Japanese stones produce as compared to synthetic stones. This particular polishing stone is an excellent example of the type of finish produced.

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Ken

[Ken Schwartz]

Here’s a closeup of a section of the blade demonstrating how the Hakka Tomae clearly differentiates between the core steel and the cladding. Also note the transition area between these two steels.

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Ken

[Ken Schwartz]

Ken, I am about to order a Japanese knife from CKTG. It’d be great it if you were willing to finish the knife on Japanese natural stones and post before and after pictures here. Please let me know if you want to do this.

Absolutely!!

You had to ask? 🙂

Just ask Mark to ship directly to me. If you need the address, just send me a PM.

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Ken

[Ken Schwartz]

Ken,

So excuse a novice sharpener, but all this discussion about natural stones… is this sharpening just the edge of the knife, or more of the surface of the knife as well? Do you have any photos you can put up that show this end result. A before and after would be wonderful if you have it too.

Thanks

Thomas

Thomas if you are up for it I would like to put a natural stone finish on the knife you just posted. A perfect opportunity to show a before and after.

Please send me a PM. This would be an interesting project (at no cost).

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Ken

[Ken Schwartz]

Ken, this is beautiful! I didn’t know that some natural stones leave such a finish. Is that because the abrasive stuff in the natural stones is softer than in most synthetic stones? It gives a beautiful finish. (And now I know it, I suddenly see this finish on many other Japanese knives.)

But what is absolutely amazing are your sharpening skills.

:woohoo: :woohoo: :woohoo: :woohoo:

And then: three degrees! And then just go to five degrees and know that it is five as if you do nothing else all day :woohoo: .

And then such a beautiful beautiful knife :cheer:.

I am going to drop dead in just a minute… :silly:

“I didn’t know that some natural stones leave such a finish. Is that because the abrasive stuff in the natural stones is softer than in most synthetic stones? It gives a beautiful finish. (And now I know it, I suddenly see this finish on many other Japanese knives.)”

Your reasoning is exactly correct. Aluminum oxide and silicon carbide, two of the more common abrasives in synthetic stones are FAR harder than the natural abrasives found in Japanese Natural stones so there is very little differentiation between how they react or treat the softer and harder steels. The natural abrasives are both softer and more varied in particle size distribution and individual particle makeup. The shapes of the individual particles themselves are not the precise spheres and other regular geometric shapes we see in synthetics and compounds, but sometimes are more flakelike or have other shapes that are more mine specific. The binding mechanism is different too than the binding sysytems employed in synthetic stones.

Mark, my sharpening skills are not as amazing as you are saying at all. Let me clarify. When I got this knife used some time ago I resharpened it using a device I made for controlling angles and at that time I made a symmetric triple bevel with the device at 3.0 degrees, followed by a microbevel at 5.0 degrees followed by a third bevel at 7.0 degrees – three distinct bevels, per side with all three bevels per side (six total ALL polished up to a fine grit level (I believe it was a 16k Shapton GlassStone finish if I correctly remember it.). I did this as a technique demonstration at the time because I knew of no other device capable of doing this (still don’t).

I could not do this freehand and don’t think anyone else can do it either because doing it (especially for 311 mm at the same three angles) is, IMHO beyond the mechanical abilities of the human hand to do freehand at this level of precision.

What I am doing in this video is much more humble a goal. I am blending these three distinct angles into a convex bevel – much like smoothing out the corners of a stop sign into a circle. This convex grind is often referred to as a hamaguri grind. This is within the limits of human precision. I am also doing more of a zero grind – in other words there is NO bevel on the edge at all – just the two sides of the knife meeting. This is accomplished by pressing very close to the edge of the edge. So this edge is somewhere between a zero grind and a very acute thinned hamaguri grind.

Here this stone is somewhat softer than a Shapton and the mud acts to give a less precise grind, allowing the rounding or convexing to occur – favoring the conversion to a hamaguri grind.

What is most interesting about this particular stone is the way it differentiates the soft cladding from the harder core steel and gives as close to a natural stone finish as any synthetic stone I have seen. Furthermore, even among natural stones, the kasumi finish or hazy finish is often less consistent than this stone. When I shot the video and first turned the edge over to see what I had done, I was about to squeal some ‘expletives of joy’ but fortunately caught myself from ruining the video. That a synthetic stone is capable of doing this is most remarkable and reflects a very deep understanding to have even created such a stone. Seeing this stone in action gives me a great deal of humility to stand before it seeing this being accomplished – far beyond my level of understanding as to how this stone was formulated.

So going back to the original topic, bringing out this level of contrast on a knife like Murray’s would be a particularly nice way to enhance or more accurately bring out the quality of his work using a natural stone finish. His steels are very traditional Japanese steels so doing this would be a very nice matchup.

Doing this on the Wicked Edge would allow producing this effect to be done with precision. I have natural stones mounted on the WE platform specifically for this task – going from coarser natural stones like the Amakusa and natural Kyushu Ohmura to natural Aoto, Binsui, Igarashi and Yaginoshima Asagi to name a few. I had planned to introduce these a bit later to the Wicked Edge, but given an interest, I can certainly move this along more quickly.

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Ken

[Ken Schwartz]

Natural stones, among other things, provide a ‘natural stone finish’.m This finish treats the core steel differently than the softer cladding steel, providing contrast between the two and revealing structural characteristics of the knife. Rather than giving the same shiny finish to both steels, the softer steel produces a matte finish because it more easily is scratched by the natural stone and the core steel gets a shiny finish but with a slight black haze to it or kurobikari finish. This reveals the structure of the steel, giving the knife a most interesting finish. Some rare synthetic stones also produce a similar effect such as the Nubatama 2000 grit stone as seen in this video

Where I ‘convert a typical synthetic stone finish to a finish closely resembling a natural stone finish. Note the change in contrast on this blue steel knife (specifically aogami super).

So in a sense these stones represent a parallel series of stones with some fascinating characteristics of their own. You can transition from synthetic stones to naturals at any point along the sequence of refining an edge and you can follow the natural stones with compounds as well and even use compounds on naturals as a component of the slurry.

The edges produced are quite different especially under a scope, and have different characteristics particularly as regards edge longevity. You will also find that for instance for some tasks the particular toothiness of an aoto (medium grit range natural) will provide an edge very well suited for a butcher – not overly refined but very pleasant to use for meat cutting. This is a very long topic and one that would completely take this thread way off topic.

Natural stones ‘react’ in an individual manner to different steels and different methods of using steel by individual knifemakers, so in my opinion a knife made using traditional Japanese steels by a traditional Japanese style knife maker like Murray would react very favorably to sharpening with natural stones.

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Ken

Ken,

First i have to get a WEPS, currently not scheduled to ship until end of April. I also ordered the ceramic stones, and a full set of Choseras. Where would these “natural stones” fit into the progression, or how would i make use of them?

Thanks

Thomas

[Ken Schwartz]

These would look even more beautiful with a natural stone finish on them. Thiis provides contrast between the soft cladding or jigane and the harder core of white or blue carbon steel or hagane.

And yes I do have some natural stones available for the WEPs for just such a knife.

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Ken

[Ken Schwartz]

So we have discussed the various types of equipment available for stone flattening up to this point. Overwhelmingly, I prefer to use diamond lapping plates for this task and will focus on this for the remainder of this discussion and let the reader extrapolate from that how to use other surfaces for flattening.

The purpose of flattening is straightforward – to produce a flat surface. This is different than producing a surface that is parallel to the back of the stone to form a perfect rectangular cuboid, but this will be covered in more detail in a post to follow.

So why do we want flatness? Well this is actually an interesting question.

I believe the answer to this is that we want a very close and uniform contact between the stone and the knife edge. Why? To give a uniform result. We don’t want to just be hitting high spots but rather we want to generate a uniform surface so that as we proceed from one stone to the next we are hitting the same surface evenly. And also producing a uniform surface on the edge as well (either flat or convex but uniformly so. Otherwise if all our stones are of varying levels of ‘non-flatness’, we would be hitting different spots with different stones and just get a mess or patchwork – wasting metal and stone and getting an inferior result.

A flat plane also constrains the surface a bit more than a convex or concave stone surface or just a random ‘wandering surface’ since after all any point on the surface of the stone must be no higher or lower than the two ends of the stone even if the surface isn’t perfectly parallel to the back surface of the stone. This will be discussed in detail later. The design of the WEPS also takes advantage of this property too as we will see in the next topic.

So to produce a flat surface you need a flat abrasive surface that doesn’t easily ;loose it’s flatness that can wear the stone down until a flat surface is produced on the stone. We will refer to an unflattened stone or stone needing flattening as being ‘dished’.

Stone wear patterns are relatively unique for hand sharpeners – almost like a signature. For a device like the WE, you will still have a signature pattern – still unique to each sharpener. Just as a diamond plate will wear unevenly, a stone will too. Typically you will not – and should not – sharpen to the very ends of the stone so you should expect the least wear on the ends of the stone or diamond plate. This will result in a concave surface on your stone. You also won’t wear the left and right side of the stone evenly, usually with the middle area highest but not always (individuals vary). Now if you let this go too far the sharpening angle will vary and you will get some degree of a convex rather than flat grind. This isn’t necessarily terrible, BUT if the next finer stone doesn’t have the same shape you get a different profile which is bad. The simplest solution is for all your stones to have the same shape, eg all equally warped. BUT the simplest shape to standardize on is a flat plane – zero warping.

Now a stone can have more wear in the center of the stone. How the hell would you do that? Well if you sharpen on the diagonal of a stone and alternate a diagonal going in the other direction you get an ‘X’ pattern. The overlap of the ‘X’ gets hit twice and wears fastest. So if you are just looking at the stone matching the flat surface, you will miss this and just see the outside flush with the lapping plate.

One of the simplest ways to correct this is to put horizontal and vertical lines on the stone with a pencil in a grid pattern – 3-4 strokes along the length and 5 or 6 across. Now as you lap the stone, you check for the remaining grid pattern. The area that remains of the grid is the DEEPEST part and you must remove stone to get EVERYTHING else ground down to that level. So you increase abrasion rates locally by pressing harder on the spots you want to grind fastest. That means pressure AROUND the deep spot, not on top of it.

So the typical wear pattern on a WE will be wear on the ends happening slowest. Some narrow knives won’t even use the ends of the stone on top. Most people won’t go all the way to the bottom either. This is EXPECTED and not at all unique to the WEPS but common among almost all types of sharpeners. The Pro model EdgePro tries to get around this with a ramp like device, but the cure is actually a worse solution and IMO should be disabled.

So typically you get a concave surface. So when you put the stone against the flat diamond lapping plate the two ends will touch and you get a gap in the middle. GENTLY abrade the stone surface applying pressure at the two ends of the stone. In time these two ends will come down to the level in the middle and you will get a flat surface. Just that simple. If the stone is bulging out in the middle, I tend to abrade the middle of the stone against the plate roughly perpendicular to the plate and gradually rotate the stone until it is parallel to the plate and all pencil lines are removed. In time you will need to use the pencil grid technique less and less.

It is best to do this a little at a time. It is best NOT to let a stone badly dish but just do fine adjustments or tuneups often. How often? This is a topic of endless debate. I prefer more often keeping stones more precisely flat. Similarly, I like to keep a knife sharp with minor tuneups rather than letting it get very dull and doing a major overhaul of the edge and walking around with a dull knife. If you do this with your finer grits, you can use a finer grit plate – 400 grit Atoma or DMT coarse or similar grit. If your stone is badly dished a 140 grit is preferred. For coarser stones a coarser grit is also preferred since this will give your stone more ‘bite’. For your finest stones you can – after achieving flatness – texturize or surface condition the stone for improved performance. Texturizing can be another subtopic.

People new to this will say ‘Why should I flatten so much – Isn’t this a colossal waste of stone?’ Actually no it isn’t. A badly dished stone wears fastest at its lowest points and the stone will eventually fail at these low points, leaving you with a badly deformed stone, and a lifetime of poorly shaped edges coming from that stone that prematurely fails.

To give a perspective on this a 5k Shapton stone properly flattened almost every time you use the stone will last you for YEARS.

How flat is flat? This too is a topic for debate with opinions varying from don’t worry about flatness to I It must be to a ten thousandth of an inch or some extreme. Remembering the phrase, ‘The enemy of good is perfect’ we need to strike a balance here. I’ll restrict my comments to synthetic stones here for now and expand on this topic for natural stones if anyone is interested.

So you can flatten against another stone. I find I prefer more precision than this. At the other extreme, you can flatten with a very high precision diamond platen like the Shapton diamond lapping plates or some industrial steel platens. In my opinion, it makes little sense to go to extremes of ultra precise flattening plates if you cannot precisely determine when your stone has reached the point of being as flat as the plate is capable of letting you be when flattening a stone. If you get a coarser stone flat to a ten thousandth of an inch and after a few strokes it is off by a couple thousandths, you are just playing around. Ultimately the issue of relative flatness is a personal judgement call and the removal of all the pencil marks is adequate enough IMO for all my sharpening needs – and I’m a very picky sharpener. I find the use of Atoma plates and DMT plates more than adequate for flattening duty.

Stone flattening should be done using water on a diamond plate. I prefer a plate equal or (better) larger than the stone itself. If you are using a similar sized stone you need to take care that the ends are getting abraded and that as the ends of the stone pass the plate that the stone stays flat to the whole plate.

When using water you generate ‘mud’ as the abraded stone combines with water. This mud will eventually clog the diamond plate making it less effective. This is easily remedied with a nail brush. A quick swipe or two quickly cleans out the impacted mud from between the diamonds and lets you continue to quickly remove stone until it is flat. There are uses for this mud so you don’t necessarily need to just discard it. Sometimes if you are just doing a minor amount of flattening, just leave the mud on the stone and it will give you more rapid abrasion of the steel. This sort of flattening can be accomplished in just a few seconds or a minute before using the stone for sharpening. There are other uses for mud – yet another future topic.

Now when you flatten a stone, especially when wet, the surface of the stone and the plate more and more precisely match, getting closer and closer. When it gets close enough, surface tension of the water comes into play as an ever stronger force and the plate can eventually BOND to the stone.

This is called STICTION. A flat continuous surface of diamonds can build up very strong stiction forces. If the diamonds are sufficiently coarse this is a less strong force. As the diamonds get finer stiction forces increase, so much so that the stone can stick to the plate making in near impossible to remove. Practically the DMT XXC or Atoma 140 have little stiction. A 400 Atoma also has little stiction but a DMT coarse of similar grit does have stiction issues. There are several solutions to this:

More water. This reduces the ability to squeeze out the water between the stone and the plate.

Less pressure

More speed. Keep things moving.

Don’t have a continuous surface. Here the Atoma plates excel, with clusters rather than a continuous surface. This allows you to use an even finer abrasive and because there is a gap between the diamonds stiction is GREATLY reduced letting one go up to the 1200 grit plates with little stiction issues.

Flattening stones is as much a part of sharpening as anything else relating to sharpening. It is a FUNDAMENTAL skill to acquire.

I’ve alluded to future topics of discussion and most likely have overlooked some other subtopics, so hopefully this initial posting will generate questions and alternative opinions or points of view. I haven’t discussed if you like to do circular flattening strokes or linear ones or strokes all in the same direction or cross patterns for instance (personally don’t feel it is important), but welcome alternative opinions on the topic.

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Ken

[Ken Schwartz]

Thanks again, Ken. I think I understand your explanation of the difference between stones and plates. The only thing I don’t understand is that these stones are so expensive. The Wicked Edge diamond stones cost $65 for two paddles. That is not exactly cheap, but also not hundreds of dollars per stone. Or are the WE diamond stones technically diamond plates?

And to make a shortcut: is a course or medium WE diamond stone suitable for flattening a fine WE Chosera stone?

I probably shouldn’t go too deeply here as it will only get confusing and off topic. When I reference ‘stones’ vs plates, I’m referring to the WE diamonds as plates – Just like DMT or Atomas or films are plates. They have a layer of diamonds on their surface. When I mention ‘stones’, that is really a misnomer for a chunk of material that has diamonds going down into the matrix not just on the surface. Typically this is a metal matrix, not a stone matrix. In all likelihood you will never see one outside of an industrial environment. They are quite expensive because they have a LOT more diamond in it and (having tested one) are largely unsuitable for hand sharpening.

I would think the WE plates ARE suitable for stone flattening, but would suggest using water for this task and being careful to cover the whole stone. More about this later …

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Ken

[Ken Schwartz]

I’ll be there! It’s official 🙂 This should be great fun!

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Ken

[Ken Schwartz]

It is COMMON, almost the rule, that Japanese double beveled knives THEMSELVES are not symmetric, so you would expect to see this on a WEPS. In this instance it is NOT a problem with the WEPS but a characteristic of the knife itself. Most Japanese knives are biased towards the right.

The simplest approach is to create an edge that has a similar amount of asymmetry to the knife itself. And the simplest way to do this is to simply grind more on one side or the other to adjust asymmetry, rather than coming up with some complicated and unnecessary setting of two different angles on the two sides.

What is important is to be consistent – clamp it the same way each time.

I suspect that this asymmetry is not unique to Japanese knives alone.

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Ken

[Ken Schwartz]

Clay, I have to compliment you on doing some OUTSTANDING work demonstrating the capabilities of Nanocloth and Kangaroo.

I also want to make the point that using the WEPS platform to do this testing is a match made in heaven and a testament to what precise sharpening is all about!

Those micrographs are STUNNING and demonstrate beautifully what I’ve been saying about these compounds and strops and the importance as you get finer compounds of the effects of the substrate on masking the effects of the compound.

I hope you don’t mind if I quote your work and use these pictures elsewhere to further promote your work and the products on the WEPS platform.

I could more obviously see that getting a ‘pure effect’ or compound only effect was critical at the higher grit levels like eighth and tenth micron snd finer, but your quarter micron pics strongly suggest that the nanocloth and ‘roo may have additional benefits at even lower grits, possibly well below 1 micron. So I’m anxiously looking forward to the additional work on the coarser compounds I sent you with the additional nanocloth samples.

Using a surface that is smooth beyond the limits of light microscopy as a starting point for demonstrating other abrasive preps like the 10k Chocera is also a SUPERB way to demonstrate the scratch pattern of that stone without the confusion of residual coarser scratches. Again NICELY Done!!

Now when we go beyond eighth micron down to 0.025 microns we are talking about a particle the size of a small virus, so I suspect that the resultant scratch pattern will also be beyond the limits of ANY light microscope. Yet we may well see some differentiating characteristics in the way the light gets reflected from these surfaces using your current equipment. Something like the effect that you see using an ultrafine graticule as a prism (just wildly speculating here about what to look for) like you see doing spectroscopy. Perhaps a high resolution mirror effect visible at full magnification. Can’t wait to see the results!

Very exciting work, Clay!

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Ken

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