8K Stone Investment

[FisherMAn1298]

for sashimi / sushi preparation you could go for an 8k.
I notice myself stopping on the 3k naniwa pro or 5k Suehiro rika for my all purpose knives. Above that doesn't really improve performance on cooked meat, vegetables, etc.

So it depends what you plan to use it on wether it'll be worth the investment.

A strop is a good investment if you don't have one yet. It will probably bring you more than an 8k stone.

I love that everyone has their preference as well as favorite stone. Makes it more interesting and proves there is no one answer sometimes when it comes to which stone is best. I love this stuff, well said men!

[FisherMAn1298]

While I respect Ken's opinion I stop after my 6K Nubatama Platinum which is a fabulous stone.

How can you not respect what Ken says. He has YEARS of experience, hundreds of stones, etc. and the scars to back up his words. Wish I knew half of what he does. We all use these products, he CREATES them!

[ken123]

I haven't done a video yet of the Nubatama speckled 8k but came across this video that shows several of this stone's characteristics.

Enjoy!

Ken

[stewssy]

SNOW WHITE NUFF SAID

[ken123]

I use both stones as well as a Nubatama bamboo 8k. Each has its advantages. For a hard precise stone the speckled stone is tough to beat. For razors especially. As a general purpose stone for knives I prefer the snow white (which actually translates as pure white.)

Ken

[David_R]

Other than a polished blade, what are you hoping to get out of an 8K edge? For most food prep I doubt you will notice any difference.

[ken123]

The polish is secondary. Improved edge performance is primary if good technique is used.
Ken

[Wjhunt]

I rarely use my Snow White. It’s a good stone but my technique isn’t perfect. I usually stop at NP 3k and then a quick strop on 1 micron diamond.
I want to try that 6k platinum. I have a few 6k suehiro stones but for whatever reason they don’t seem to improve my edges that much.

[ken123]

I just got a few more in stock! PM me.

Ken

[David_R]

The polish is secondary. Improved edge performance is primary if good technique is used.
Ken

I'm sure I don't have good technique. Good edge performance in terms of sharpness so easier cutting?

[ken123]

It does come with practice especially at higher / finer grits.

Ken

[orezeno]

The polish is secondary. Improved edge performance is primary if good technique is used.
Ken

I'm sure I don't have good technique. Good edge performance in terms of sharpness so easier cutting?

Yes. That's the idea. There are situations where a highly refined edge is expected. To produce this correctly, you need to be able to properly prepare the knife on the lower grit stones.

Many people don't get a particularly sharp knife off of a 1K or 500 grit stone and assume they need finer grit stones to achieve sharpness. The opposite is actually true. If you learn to control sharpening angle, bevel shape and symmetry (for symmetric knives), and edge uniformity, you can get a screaming sharp knife from a 500 grit stone. Once you can do this, and can be consistent with your motion from stone to stone, then the amount of polish and refinement from a progression to (something like) 8K will be noticeable; though you may be surprised by how relatively small the improvement above 1K-2K really is.

[David_R]

The polish is secondary. Improved edge performance is primary if good technique is used.
Ken

I'm sure I don't have good technique. Good edge performance in terms of sharpness so easier cutting?

Yes. That's the idea. There are situations where a highly refined edge is expected. To produce this correctly, you need to be able to properly prepare the knife on the lower grit stones.

Many people don't get a particularly sharp knife off of a 1K or 500 grit stone and assume they need finer grit stones to achieve sharpness. The opposite is actually true. If you learn to control sharpening angle, bevel shape and symmetry (for symmetric knives), and edge uniformity, you can get a screaming sharp knife from a 500 grit stone. Once you can do this, and can be consistent with your motion from stone to stone, then the amount of polish and refinement from a progression to (something like) 8K will be noticeable; though you may be surprised by how relatively small the improvement above 1K-2K really is.

Are you saying most people thing higher grit = more sharpness or a "better" edge because they can't get a sharp edge off a 500 grit stone? If that's the case, I question how they're getting a sharp edge off an 8K stone.

I would not be surprised by how little the improvement there is over 1-2K. That's why I'm asking what the improvement is at 8K. Objectively sharper? I don't think so. Better edge retention? Nope. Probably not worse edge retention depending on the steel, but not better. I imagine the cutting experience or feel could be different/better to some at 8K.

[orezeno]

Are you saying most people thing higher grit = more sharpness or a "better" edge because they can't get a sharp edge off a 500 grit stone? If that's the case, I question how they're getting a sharp edge off an 8K stone.

Generally, when we're first starting out, we don't get a very sharp edge off of any stone. Over time, we learn what sharpness really is for a particular steel, bevel geometry, and (most importantly) function. Most people buy a set of stones (coarse, medium, and fine) and assume that sharpness is achieved by going through the full progression.

I would not be surprised by how little the improvement there is over 1-2K. That's why I'm asking what the improvement is at 8K. Objectively sharper?

Measurably sharper; assuming the sharpener has control of his/her craft.

I don't think so. Better edge retention? Nope. Probably not worse edge retention depending on the steel, but not better.

Edge retention is a characteristic of the material (generally steel, but not necessarily). It will vary depending upon edge geometry, so for testing there are specifications on edge geometry. Typically, the edge width is kept constant (within tolerances) so performance between different materials can be compared.

I think what you're getting at is that you would not expect a highly refined edge to last as long as a less refined one for a given knife. Generally speaking, this is a reasonable assumption. For a given force applied to a knife, pressure at the edge increases as the edge width decreases (on the order of force ÷ edge_width**2). Higher pressure at the edge results in higher stresses in the steel at the edge which increase the rate of material breakdown.

However, in theory, a sharper knife should take less force to cut the same way as a dull one, so a user could use less force to adjust for the fragility of a very sharp edge. (I have yet to see this happen.)

I imagine the cutting experience or feel could be different/better to some at 8K.

There is definitely a different feel. People develop preference for the feel they want. OTOH, some knives (e.g. a yanagi) are expected to have a highly refined edge.

[Wjhunt]

I’ve always tried to get rid of the scratches from the previous stone when I use the Snow White. I’m going to have to try Mark’s approach and just do a few strokes on it.

[Mowgface]

Damn... people still sharpening kitchen knives they actually use up to 8K???

Unless its a Yanagiba, would never go higher than 6K. Barely go to 6K anymore except for looks, I'm in the 3-4K camp.

[lsboogy]

Damn... people still sharpening kitchen knives they actually use up to 8K???

Unless its a Yanagiba, would never go higher than 6K. Barely go to 6K anymore except for looks, I'm in the 3-4K camp.

Most of my daily drivers are 6K or better - I'm in the 6K min camp

[Altadan]

Just a home-cook here, but I can happily say that Shapton glass 500 with a jump to shapton 2k has kept me happy for all my kitchen duties excepting the yanagi and deba (which get the 6k followed by 7k-10k jnats). I used to sharpen to 6k, but got tired of soaking, and didn't really find a need for it neither for veg nor most meats.
Hope this helps

[cliff]

Most of the time, I go from SG 2K to 6K. Every month or three, I'll throw in the SG320. Or I'll go Natsuya to Aoto and then higher, or not, depending.

[David_R]

Measurably sharper; assuming the sharpener has control of his/her craft.

Interesting. Can you point me to any measurements? Over7-8 microns I don't see any edge retention improvement. I don't have a sharpness tester.

Edge retention is a characteristic of the material (generally steel, but not necessarily). It will vary depending upon edge geometry, so for testing there are specifications on edge geometry. Typically, the edge width is kept constant (within tolerances) so performance between different materials can be compared.

Edge angle and blade geometry over steel for edge retention, assuming the steel is not terrible. The same knife at 25 degrees per side vs. 12 degrees will give very different results. I've tested the same knife a 2 degree increments from 25 degrees down to 11. Edge retention continues to increase as the angle decreases. VG-10 at 12 degrees will out cut S90V at 25 degrees. Here is some well controlled and objective edge retention testing so you don't have to take layman's opinion on it.

I think what you're getting at is that you would not expect a highly refined edge to last as long as a less refined one for a given knife. Generally speaking, this is a reasonable assumption. For a given force applied to a knife, pressure at the edge increases as the edge width decreases (on the order of force ÷ edge_width**2). Higher pressure at the edge results in higher stresses in the steel at the edge which increase the rate of material breakdown.

Not quite. I don't see highly refined edges having more or less edge retention. Edge retention gets better as stones get finer up to a point. In my limited testing this is ~7-8 micron, or ~2K, depending on the stone.

However, in theory, a sharper knife should take less force to cut the same way as a dull one, so a user could use less force to adjust for the fragility of a very sharp edge. (I have yet to see this happen.)

There is definitely a different feel. People develop preference for the feel they want. OTOH, some knives (e.g. a yanagi) are expected to have a highly refined edge.

Good point. I haven't noticed this with food. An 8K edge certainly glides through paper more quietly than a 2K edge.