Ken Schwartz

[Ken Schwartz]

I do have the Atoma plates in 140 400 600 and 1200 grit available for the Wicked Edge. I find the 140 more than aggressive enough for reprofiling abrasion resistant steels and major repairs, yest still leaving a finish that doesn’t have extremely deep scratches for the level of aggression it gives. I have not tried the 50/80 stones personaly, but customers have reported comparable results between the two.

I have begun cutting Nubatama stones for the Edge Pro and upon request will cut them for the Wicked Edge. Two of the coarsest stones in the Nubatama series are 60 grit and 24 grit. Now that’s rough!

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Ken

[Ken Schwartz]

A vote for a more obtuse microbevel. You can gradually increase the angle to a more obtuse angle. Why do the whole bevel only to redo it again to yet a more obtuse angle. Besides as you continue to use the knife you will have to thin behind the edge. This way that work is already done.

Remember that it is far more work to go more acute than to go more obtuse.

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Ken

[Ken Schwartz]

This should help simplify the discussion of this often confused topic:

Note that there is a difference between a 10/0 grind on a honesuki and a yanagi, where the yanagi has a hollow grind back. Sharpening techniques for the two are quite different.

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Ken

[Ken Schwartz]

Just another approach:

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Ken

[Ken Schwartz]

For steel like S30v, diamonds and CBN are the way to go. Aluminum oxide based solutions are not. Solutions include diamond papers (I have them down to 165 microns), plates (I have Atomas down to 140 grit which work quite nicely), the plates that come with the Wicked Edge and diamond and CBN sprays and other formulations. I have CBN as coarse as 80 microns and even some 200 and 300 micron preparations. I also have other diamond and CBN solutions for sharpening S30v. You can also apply CBN on waterstones which lets s30v sharpen with relative ease.

Plates generally don’t go past 1200 grit so here you should use diamond films or compounds. I have a full range of CBN grits so it is certainly possible to use these for the entire sharpening process.

Using waterstones alone without CBN on it or papers with alox ir sic is just an exercise in suffering.

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Ken

[Ken Schwartz]

In addition to the Choceras, I have Shapton Pros in all grits 120 to 30,000 available for the Wicked Edge. I also have natural stones of various sorts as well as other stones and will soon be coming out with Nubatama stones for the Wicked edge. Just send me a PM or contact me directly at ksskss @ earthlink.net

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Ken

[Ken Schwartz]

Just a brief comment. It isn’t that the ‘roo ‘slices’ are thinner slices as much as that the skin itself is much thinner. No slicing is attempted – it’s just a selectively thinner hide.

It also isn’t that the ‘roo is a tougher hide – it is thinner. This gives you less give.

It’s also much smoother. This is immediately apparent when you feel them and compare the creamy smooth texture of ‘roo vs cow or horse. The abrasiveness of ‘roo is far finer in nature rather than tougher. The lack of give of the ‘roo comes from it’s extreme thinness. If it were backed with a soft backing, it would be quite supple enough to be used for convex edges, but with the Aluminum backing it is quite firm. The only thing less abrasive than the ‘roo is the nanocloth, which is the absolute minimum of interference with the qualities of the applied compound, yielding a pure compound effect. The ‘roo does have a draw or burnishing effect which the nanocloth doesn’t. I’ve gotten excellent results with both nanocloth and ‘roo, so you won’t be disappointed with either.

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Ken

[Ken Schwartz]

So I guess where I’m going with this is to explore what natural stones do and some thoughts regarding ideas of increased edge longevity using Japanese natural stones. You’ll see how this relates to this topic in a bit.

Synthetic stones have a grit number assigned to it. So you might have a 2000 grit stone for instance. Natural stones don’t have a grit number that can be assigned to them, even though people try to do it.
Synthetic stones usually have aluminum oxide as their abrasive (I’m leaving out details to keep from going off in tangents here). Depending on stone quality, these can be pretty precisely graded. The abrasive particles are more or les spherical in shape – cubes spheres polygonal shapes – and they stay that way. Naturals (Japanese by default)are a much more varied structure, with particles of different hardnesses and sizes and shapes. You might have particles shaped more like corn flakes. How do you measure the size of a cornflake – it’s length width or thickness? Or it’s surface textures? Now if this wasn’t complex enoungh, what happens if you use these flakes and in the process of developing mud on the stone, the flakes break up into smaller flakes? Pretty complex.

So what is the result of this? It is a slurry that refines itself as you are using it! It gets finer with use.

So now we have a scratch pattern that contains various scratch patterns. Do you see where I’m going with this? Now you have an edge with various ‘sizes’ of ‘teeth’ so when you ‘use up’ teeth of one grit another level of teeth comes into play. Interesting stuff, isn’t it? you don’t get a single point of failure but rather a graded sequence of failures.

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Ken

[Ken Schwartz]

Let’s split this up a bit. If you are sharpening at two different grits on the 2 sides of the knife, the symmetry or lack of it is a separate issue – unrelated. So you could do this on a symmetric or asymmetric grind.

I’m not quite sure what the advantage of this would be, but if you wished to go back and forth between compounds and stones in a progression, you could do it. Unorthodox, but I’ve done it.

So finally why would you do it? If you wanted a combination of toothy and refined why not do it the same way on both sides? I’m confused about what you are trying to achieve. Please clarify this and maybe I could come up with something.

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Ken

[Ken Schwartz]

A microbevel is just a tiny bevel less acute than the original bevel.

So you can make a microbevel from a single stroke of a high grit strop (and see it under a scope) or make a much larger one with a coarser stone too. The level of refinement, the number of degrees difference is up to you.

The purpose of a microbevel is to make the edge less acute. This gives you a more durable edge, trading acuteness for toughness. You typically use it if the existing angle is too acute FOR THE TASK you wish the knife to perform.

You can do a series of less and less acute microbevels and combine or blend them into a convex grind, or just use a softer substrate to generate a convex grind (with precision when using a Wicked Edge. For this task, I utilize neoprene mounted on a paddle with an abrasive substrate (nanocloth or Kangaroo usually) over it with abrasive applied (CBN or diamond usually). Harder substrates produce less convexity.

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Ken

[Ken Schwartz]

[Ken Schwartz]

http://youtu.be/dDsWh_M7Rekhttp://youtu.be/dDsWh_M7Rek

(Can’t seem to embed the video)

This shows the concepts behind doing asymmetric bevels on a grinder but it translates very nicely on the Wicked Edge. You actually have far more control with the Wicked edge with the additional benefit of even using two different angles if you wish (not a requirement).

Just set the angles on both sides – usually the same angle. If you wish to shift the asymmetry to one side or the other just grind more on that side.

Note that you can maintain angle asymmetry and go more or less acute in terms of the overall included angle.

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Ken

[Ken Schwartz]

SO I guess the point I’m trying to make is that it is best to not think of things in terms of stropping honing and sharpening but rather to just call them ALL abrading. So to answer your last question first, a 15 micron strop would be far rougher of a finish than a 10k stone and would be going in the wrong direction.

So saying strops do this and stones do that is wrong. It’s all about the particle size as the major factor. An 80 micron CBN strop cuts way faster than a 10k stone. Not even close.

Does a 15 micron spray leave the same scratch pattern as a 1k Chocera. Not really. It is a simplification to compare all particles on all media as giving the same result just because the particle size is the same. Apples and oranges are about the same size but taste different for example. So most stones are aluminum oxide based (generalization). Compounds can be Aluminum oxide, CBN (cubic boron nitride, polycrystalline or monocrystalline diamond, etc etc) Each of these have different abrasive properties based on particle shape particle hardness, etc etc.

Hope this helps. It’s just the tip of the iceberg.

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Ken

[Ken Schwartz]

15 microns is roughly equivalent to a 1k Chocera stone in terms of grit size. I use particles as coarse as 80 microns on strops, but at that size (I have CBN particles as large as 300 microns) you start running into ‘issues’ using regular strops. I do use 30 and 45 micron particles as strops – nanocloth and leather. They ‘sink’ into balsa only partially sticking out. If the substrate is too hard they roll around.

An interesting approach to larger particles is to use a waterstone as the strop substrate! There is one caveat. The carrier for the particulates must be water soluble!! Otherwise it can damage a waterstone.

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Ken

[Ken Schwartz]

On leather I just add a bit more of the abrasive spray when necessary. Leather on alcohol is pretty harmless, drying more rapidly than water, but it can eventually loosen the glue attaching the strop to the paddle.

On nanocloth you can refresh with a water mist, although I rarely do this. If you are being picky I’d suggest deionized water, which is less likely to produce particle agglomeration which could be misinterpreted as a more aggressive finish from the clumped or agglomerated particles (larger micron size).

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Ken

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