Natural Water Stones

[Fred]

They have arrived and I'll start testing sometime this week. Strangely, these two stones, 6" X 2 1/2", are made in Australia, not Japan, from imported natural stone (presumably from Japan.) One is 3/8" thick and the other one is 5/8" thick.

http://www.foodieforums.com/otherimages/nwaterstones.jpg

Any suggestions or comments before I begin testing and reviewing?

[louisianacook]

Interesting, those are new to me. They sort of look like my Belgian blue stone I recently purchased, but would have see them first hand before I was sure. What did they cost? For reference my blue Belgian, 8"X3 1/8"x1/2" was $70.00. The claimed grit for the blue Belgian is 4000. What else does the box say on it?, just curious. You say they are made? as in manufactured from ground up smaller natural stones and reformed with a new binding agent? Do the stones have faults running through them?
Lee

[Fred]

I assume the stones went from somewhere to Australia where they were cut and packaged. They are natural stones. The thick one has "faults" in it. Now that I look at it, the thin one does too but only on the sides. The box also says "approximates 6000 grit JIS" so it is a finishing stone. I bought these wholesale from one of my cutlery suppliers. I would assume the retail price would be around $40 or so. That seems to be in line with yours since yours is a larger size. We'll see how it goes.

[Peter]

Lee, do you like the Belgian stone (Coticule)? It would be interesting to compare them to Japanese stones.

I own one which I bought at the Coticule museum in the Ardennes. It has two sides, a blue one and a yellow 6000 grit side. The yellow sediment is very rare today.

Peter

[louisianacook]

Peter, i think the "blue stone" side of your coticule is actually slate, and should not be used for sharpening.. I have a large coticule on order from Howard Schecter, he is the US importer for Belgian stones. I hope i like it for $175 Sounds like you have a very nice old stone Peter.
Lee

[TATATA]

Hi,
It is the whetstone with an interest.
Is it an oil whetstone?
There is not a natural oil whetstone in Japan.
I have a lot of Japan natural whetstones.
Those particle size are very small it is about #10,000.
There are those photographs in our Web.
http://www.suisin.co.jp/tennen-set/index.htm

I am thinking that a Japanes natural whetstone fits carbon steel.
I am interested which fit steel your natural whetstone.

[Fred]

No, it is a water stone and the box says it is the equivalent of 6000 grit or particle size. I haven't tested it yet but I will test it on both carbon steel and stainless steel to see if it works differently on either type. I didn't realize the different steels would react differently to the stones. Thanks for the input, Tatata.

[Oded]

Hello Tatsuya,
Is there a relation between the hardness of the whetstone and the grit?

[Peter]

I know what you mean but this is a true two layer stone, the yellow side is ~5mm, the blue ~15mm. There's a photo on their web page (http://translate.google.com/translate?u=http%3A%2F%2Fwww.mediardenne.com%2Fmus ee%2Fcoticule%2Fcoticule1.htm&langpair=fr%7Cen&hl= de&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools).

I didn't see it on any website and I doubt I ever will.

But I really don't know if Japanese stones are even better.

Peter

[Peter]

Hello Tatsuya, it's good to meet you, a true professional.

Do you have a recommendation for blue steel and carbon steel knives, Gyuto and Petty?

Peter

[Fred]

The test will take a little longer. Surprisingly, the natural stones work up a pretty good slurry and wear fairly quickly. I'm four knives into the test and the stone is getting better with each knife. It looks like all the original grinding marks on the stone have now been smoothed and the stone feels like a 6000 or 8000 grit man made water stone. I think at this point I can probably do a fair test. So bear with me.

At least I got my parer, my petty and my two sujihikis all tuned up. Now on to some gyutos and yanagis.

[louisianacook]

Those stones sound more like what I get on the Belgian blue, a fairly quick and abundant slurry. To get the same amount of slurry on my Japanese awase I need to get the nagura out to get the slurry going.
Lee

[Fred]

I used the nagura.

[Scott]

Lee,

How well does your blue stone cut compared to your others?

Scott

[louisianacook]

Faster, but it is a lower grit, so I really can't compare them that way. It does raise a slurry very fast, even without the nagura treatment. Seems they wear a little faster as well...
I am still playing around with it, but still like my Norton 4K for that grit range, the Shapton 5K polishes more than cuts in my opinion, but again they are not the same grit.
Hope that made sense.
Lee

[yuzuha]

I'd be very interested in your review of those. I have a natural aoto blue stone and an awase (probably about 10-12k) and find that they both work up a slurry that makes them rather pleasant to use, and that they leave a different finish than artificial stones... posssibly what sword polishers refer to as "opening up" the steel leaving a sort of velvety sheen (rather than glazing it over into a mirror polish).

I think I'm becoming a fan of natural stones and would like to try more of them, so I'm interested in your observations as to the hardness/softness and type of finish your stones leave on various steels.

[yuzuha]

[ QUOTE ]


http://www.suisin.co.jp/tennen-set/index.htm

I am thinking that a Japanes natural whetstone fits carbon steel.
I am interested which fit steel your natural whetstone.

[/ QUOTE ]

Very interesting Tatata. I ran your web page through an online translator, but the English was not very clear. Could you tell us more about your stones?

I have an aoto blue stone (mostly use this for sharpening kitchen knives) and a Tsukuba awasedo (I use this on wood carving knives and to polish the sides of blades... cost about 20,000 yen so the quality is probably not as high as some of the stones on this page http://shop.niimi.okayama.jp/kajiya/en/shop_e/toishi_e.html# )

I don't know how much I can tell you about how natural stones work on Western steels since I only have 2 natural stones and have only tried a few different steels...
I have tried my stones on carbon steel (hard Japanese and softer Western carbon steel), soft German stainless steel, BG-42 stainless and on M2 and D2 tool steels. I do find that they work best on carbon steel (both Japanese and American), but they also work fine on European stainless (Wusthof & Henckel's... mine have a mirror finish now ^-^)

BG-42 is a bearing steel used in jet engines, but can take a very sharp edge and makes a good long wearing knife when hardened to Rc61. It polishes slower than carbon or German stainless, but it also seems to absorb some of the mud and leaves a hazy finish.

D2 is a very coarse grained, hard wearing steel so it grinds slowly... the awase leaves a very smooth finish, but the steel is so coarse grained that the mud gets into the steel and makes it look gray-brown.

M2 is a very wear resistant high-speed tungsten steel used for cutting other kinds of steel. It seems a bit harder and more wear resistant than D2 but has a finer grain. It takes a nice mirror polish from the awasedo (a little of the mud sticks in it but it is not impossible to clean out leaving a nice mirror polish... not a glass-like a polish that my K0705 Shapton stone leaves, but I think the Shapton also burnishes the steel... funny, the Japanese site lists the k0705 as #12000 grit http://www.shapton.co.jp/ but the US site http://www.shaptonstones.com/stones/Professional-Series.php says #15000 grit. Which is right for .96 microns? )

My natural stones seem to grind just as well as artificial stones (hard and soft Suehiro clay or Shapton & Global ceramic), but are more fun to use (very smooth buttery feel that is just much nicer than the feel of grinding on artificial stones, with or without nagura). They also seem to open up pores in the metal while artificial stones seem to burnish and close the pores (at least, that is what it looks like under a microscope). This gives a nice satin mirror effect on some steels but the mud sticks in the pores on some of the exotic tool steels and is very difficult to get out.

[Fred]

Welcome aboard, Pam. It's obvious you have some serious cutlery experience so I'm sure we'll all learn from you. I did post the review which I completed today after working with a total of seven knives. You won't have any problem finding it. Glad you could join us.

[yuzuha]

[ QUOTE ]
Welcome aboard, Pam. It's obvious you have some serious cutlery experience so I'm sure we'll all learn from you.

[/ QUOTE ]

Thanks Fred.
Actually, I don't have much experience with cutlery, but I've always been interested in materials science... geochemistry, metallurgy etc. so I find the properties of metals and minerals fascinating.

Then there is the artistry of metal working that leaves me a bit in awe... like this tanto http://www.bladeforums.com/forums/showthread.php?t=314156&page=1 The activity in the hamon reminds me of Hokusai's block prints of a stormy sea http://www.andreas.com/hokusai.html

Your stone review corresponds to my observations as far as practical sharpening (my awasedo cuts about as fast as my Shapton 15k and leaves a similar edge, but very different surface textures). For sharpening, synthetics work just fine (and there is variation in them as well... maybe use a hard stone for soft steel to control that edge geometry and a soft stone on hard steel for a bit of micro-convexing). I just find the swish-swish sound and the blade gliding on the mud of natural stones to be strangly satisfying, and I like their polishing action better (I guess not too many people polish the sides of knives for the heck of it, but I'm a nut-case who'll polish a knife or block of metal and then sit an examine it under a stereo microscope to try and get a feel for the action of different abrasives on the surface structure of different metals ^-^)

I'd love to try out some of those $15,000.00+ sword polishing stones, but my guess is the difference between them and artificial stones is mostly in the handling and polishing action rather than sharpening ability. Since I can't afford such things anyway, I'm afraid I'll mostly have to experiment with synthetics... even with them, there is a big difference in hardness and action... clay or cermaic bond etc. It would be interesting to see reviews of things like "how do Naniwa super stones compare to Shaptons, Kitayama, Takenoko etc. stones in the same grit, and do any of them match up particularly well to a certain kind of steel?"

[Fred]

I don't know. I don't have an example of two different stones of the same grit except for the King and Awase I tested over the past few days.

I can't answer your comment but I'll make a guess. While most waterstones use aluminum oxide as an abrasive, the Shapton stones use ceramic. The matrix that holds the abrasives on the Shaptons appears to be less water soluble and the result is stones that wear slowly compared to the more common aluminum oxide/clay based products.

Logically, you could reach the conclusion that the slower dissolving matrix would cause the abrasive particles to get more wear since they would remain attached to the stone longer rather than being washed away in the slurry. On faster dissolving stones, the abrasives would be renewed more often. That would cause one to think that the aluminum oxide stones would cut faster.

In my experience, though, they don't. I assume the reason is that the ceramic abrasive particles themselves are harder and can take more wear. Just a guess on my part.

In my experience the shapton stones cut just fine and just as quickly as other water stones but overall they wear more slowly. That means they need flattening less often and they last longer. That's why they are such a good value in my opinion.

Nevertheless, I often use the term "grits is grits." What I mean by that is that two stones with the same fineness of grit will produce about the same results on the blade steel. Some will wear faster and cut faster or whatever but, when all is finished, the blades will perform about the same as long as the "grits" are the same.

Every time I went from the 6000 grit King stone or the 6000 grit Awase stone to the 8000 grit Shapton I improved the the edge. Why? Finer grits, of course. If I were to go from a 5000 grit Shapton to an 8000 grit Takenoko, I feel certain I would again improve the edge. While I haven't tested this combination I don't feel I need to. I'm confident about the result.

I've concluded that differences between various stones of the same abrasive particle size are subtle at best and unimportant to the performance of the knife when it is in use. I found the edge with the Awase stone to be very slightly "toothier" than that produced by the King stone. But the knives cut the same when all is said and done. If they cut differently then I would view the differences as so small as to be meaningless.

I have no intention of spending hundreds of dollars on a large Awase stone. I'd just be able to improve the results with a relatively inexpensive man-made stone. I didn't mean for this to turn into a rant. Sorry.

[yuzuha]

[ QUOTE ]

I can't answer your comment but I'll make a guess. While most waterstones use aluminum oxide as an abrasive, the Shapton stones use ceramic. The matrix that holds the abrasives on the Shaptons appears to be less water soluble and the result is stones that wear slowly compared to the more common aluminum oxide/clay based products.


[/ QUOTE ]

AFAIK, Shapton stones use chrome oxide Cr2O3 which has a mohs hardness of 8.5 and a crystal structure similar to aluminum oxide. I don't know what sort of cermic they use as a binder (probably a trade secret) Belgian blue and champagne corticle stones are a type of slate with dodecahedral garnets (hardness 6.5-7.5) in it. Aluminum oxide comes in several forms with various bonds including sintered. Usually forms short hexagonal crystals (as in the native forms sapphire and ruby) that are very tough and have a hardness of 9. Silicon carbide has a hardness of 9.25 but forms rather fragile crystals that shatter into sharp blade-like shapes (good for soft non-ferrous metals that won't grab and break the crystals and for glass/ceramics. Stones made of this will hog out steel but will tend to dissintigrate quickly and it produces a much coarser scratch pattern than the tougher and blunt crystals of chrome or aluminum oxides). Diamond isn't recommended for steel because surface heating causes the diamond to dissolve in the steel, though this isn't much of a problem hand lapping with a coolant like water or oil. Not sure what the abrasive in natural Japanese waterstones is, probably quartz and some other mineral (andalucite? I'm hoping maybe Tatsuya can tell me since I can't read Japanese... wish I could, they have so much interesting geology)
[ QUOTE ]

Logically, you could reach the conclusion that the slower dissolving matrix would cause the abrasive particles to get more wear since they would remain attached to the stone longer rather than being washed away in the slurry. On faster dissolving stones, the abrasives would be renewed more often. That would cause one to think that the aluminum oxide stones would cut faster.



[/ QUOTE ]
Interesting thought. I'm guessing, the action would depend on the porosity of the binder, hardness and crystal shape, as well as the fragility of both the abrasive grains and the binding material (as well as the type of fracture of the abrasive... some minerals shatter into rounded grains and some form very sharp blade-like fragments like SiC) Aluminum oxide is harder than chrome oxide, but the cyrstals are similar in shape so they should be similar to each other.

[ QUOTE ]

In my experience the shapton stones cut just fine and just as quickly as other water stones but overall they wear more slowly. That means they need flattening less often and they last longer. That's why they are such a good value in my opinion.

[/ QUOTE ]
Agreed, Shaptons are nice stones (the Gobal ceramic stones are also nice in this respect... much like the Shapton M5 series.
[ QUOTE ]

Nevertheless, I often use the term "grits is grits." What I mean by that is that two stones with the same fineness of grit will produce about the same results on the blade steel. Some will wear faster and cut faster or whatever but, when all is finished, the blades will perform about the same as long as the "grits" are the same.

[/ QUOTE ]
This is what confuses me since there are so many ways to figure grits... how do you classify long thin crystals compared to rounded ones? Everybody uses a different system, and then there is "mesh" grading and water flotation grading. Even with micron grading, everyone uses a different range... a 3 micron abrasive is 3 microns measured in which direction, and then it is only a statistical average with particles ranging from 2 to 5... better manufacturers seem to have tighter tollerances. I've read somewhere (possilby Boride abrasive's site?) that a lot of people would like to grade abrasives not on the particle size but the actual surface finish they leave (depth and size of scratches they leave in a surface). Micro-mesh seems to be using this method with their sandpapers.

[ QUOTE ]

I've concluded that differences between various stones of the same abrasive particle size are subtle at best and unimportant to the performance of the knife when it is in use.

[/ QUOTE ]

Oh, to be sure. Speed and stone wear would be secondary considerations, and if you are only considering the cutting ability of a knife, I doubt if many could tell the difference between a 5000 and a 6000 grit edge, and 6k to 8k would still be subtle. Mold and die makers would be more concerned with the surface polish and grit consistancy, which is a whole different set of variables.

[ QUOTE ]

I have no intention of spending hundreds of dollars on a large Awase stone. I'd just be able to improve the results with a relatively inexpensive man-made stone. I didn't mean for this to turn into a rant. Sorry.

[/ QUOTE ]

ROFL, I wouldn't either... for finishing, a cast iron lapping plate and diamond paste or some 3m micro-finishing film would do the job for less than $30. I feel totally irresponsible for buying my Shapton and the awasedo, but both will probably last the rest of my life and I'll never buy any that expensive again. I just suffer from a rather annoying case of terminal curiosity /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/grin.gif

[Fred]

You mean Shapton makes such a big deal out of advertising their stones are ceramic and they're only talking about the binder, not the abrasive?

[yuzuha]

[ QUOTE ]
You mean Shapton makes such a big deal out of advertising their stones are ceramic and they're only talking about the binder, not the abrasive?

[/ QUOTE ]

Actually, chromium oxide is a ceramic so they are technically correct. There seems to be many different definitions of ceramic going on here. Technically, clay, ferrite, silicon carbide, aluminum oxide, chrome oxide, Yttrium barium copper oxide superconductors, plaster of paris, Uranium oxide fuel pellets, china plates, bricks etc. are all ceramics.

In terms of sharpening stones, technically every one of them is ceramic (the abrasive, binder or both), though people seem to use the term "ceramic" as a generic term for stones that can be used wet or dry (depending on how they load up) but do not absorb water, no matter how they are bonded.

Many of the oil stones seem be be sintered abrasives (varying greatly in porosity between India stones and hard black Arkansass stones which are nothing but quartz grains welded in a dense matrix by more hydrothermally deposited quartz in much the same way the gemstone opal... Anyway, there is nothing else in them but abrasive with the grains welded together in some way). A lot of the waterstones are earth bonded (abrasive grit mixed with some sort of wet clay or porcelain powder that can be baked into a brick of varying porosity and hardness)... for that matter, porcelain is hard enough to hone steel without any added abrasive so you could probably classify it as a ceramic bond.

I did some searching, and according to Shapton's site, their stones are resin bonded chromium oxide (some sort of phenolic like bakelite or epoxy, so they are really plastic-ceramic stones). Ha! Plastic is EVERYWHERE! That would explain the plastic-like feel of them and why they don't soak up water.

Paraphrasing from an abrasives company's site "Resin bonds are resilient, cushioning the abrasive against shock that might cause gross fracture. And, since resin bonds are formulated to wear at the same rate as the friable abrasive, new crystals buried in the bond are exposed when needed. As a consequence, resin-bonded abrasives generally remove material twice as fast as vitreous-bonded abrasives."

That would explain why Shapton stones cut faster than it seems like they ought to for stones that wear as slowly as they do.

Hm, you know, that's got me thinking about that dry chrome oxide powder Hand America sells, or maybe even diamond dust... mix it with the proper epoxy... DIY stones! ^-^

On the other hand, you might spend enough experimenting with it 'til you got the proper proportions that it would probably be cheaper to just buy stones (well, maybe in one case it might be worth it... I don't know anyone who would actually pay $600 for Shapton's 30,000 grit 1/2 micron stone... at least I have never been able to find a single mention anywhere on the web of anyone who has actually tried one, but then that is what strops are for, no?)

[Fred]

No. Strops, at least leather ones, are too resilient and have a tendency to round off the eges. I think it's better to polish with fine grit stone.

Thanks for the feedback. The Shapton stones sound like they are unusual and unique in the water stone world. They work quite well for me. I've used them for years. I expect I'll be using them for the duration. I haven't even come close to wearing one out.

[VHo]

Yuzuha,

I bow in your direction! your knowledge is most impressive.

The expertise around here is amazing.

v

[Scott]

VHo,

I hear that! I have been busy with some personal projects for the last couple days and all I can say is that this thread has blossomed into a real beauty! IMO, one of the best threads we have had going in awhile.

Keep it up everyone! /ubbthreads/images/graemlins/grin.gif

Scott

[mikemac]

OK...if "grits is grits", and the Shapton "faster cutting" stones seem to be the cats meow, why is there little consideration for DMT and/or Diamond stones? Granted - when I bought my duo stone, I was probably lost & confused by the mesh/micron/grit phraseology, and thought that the "fine" would equate to a natural water stone in the 1000 grit range. I've since learned it's coarser than that, but still an extra fine is available...
A comment I've read before is that the diamond stones are 'too aggressive', but isn't that the benefit of the shaptons? quick cutting?
If nothing else, I've got a nice "coarse" starting point for working on shoulders, raising a burr, and flattening my natural stones...

[Fred]

In my experience there are some problems with diamond stones. The major one is that they wear pretty quickly. Since the abrasive particles are attached permanently to something they just wear down, the sharp edges of the crystals become rounded.

Diamond stones are aggressive when they are new but are pretty coarse in terms of grit size. After they wear down, they lose a lot of their aggressiveness.

I think a diamond stone can do a great job in conjunction with water stones. You can use them for the coarse work and then finish with the water stones. I've never seen a diamond stone that was fine enough for finish work. That doesn't mean that they don't exist, of course.

[yuzuha]

[ QUOTE ]

I bow in your direction! your knowledge is most impressive.

The expertise around here is amazing.


[/ QUOTE ]

Thanks, VHo, I'm a veritable cess-pool of obscure information of rather dubious value. Besides, you know what they say about "book learning." Fred and a couple of other posters are the ones with an amazing amount of practical experience, which I lack. /ubbthreads/images/graemlins/blush.gif

[yuzuha]

I have a couple of those 10x4 DMT duosharp plates and find that they work well for roughing and stone flattening.
DMT uses monocrystaline diamonds and list their grits as
x-coarse = black = 60 micron (220 mesh)
coarse = blue = 45 micron (325 mesh)
fine = red = 25 micron (600 mesh)
x-fine = green = 9 micron (1200 mesh)
They, Norton and Ez-lap also make 6,3 and 1 micron diamond paste.
Eze-lap uses polycrystaline diamonds and their stuff is listed here http://www.eze-lap.com/product/3x8ds.htm , not to be left out, they also have double sided stones http://www.eze-lap.com/product/double.htm 3M usually grades their diamond products by micron size.

Now as for their micron-mesh ratings, find the section on "diamond compounds" on this page http://www.emsdiasum.com/microscopy/products/materials/polishing_supplies.aspx for a description of the difference between monocrystaline and polycrystaline, as well as the micron ranges for a particular mesh (um, DMT says 1200 is 9 micron, they say 1200 is 12-22 with 15 as an average. See what I mean, not only are grit ratings confusing, but mesh ratings and micron sizes can be a bit misleading ) The polycrystaline do break a bit faster, but expose new sharp surfaces (and get smaller which is probably a good thing for polishing with a paste or spray). BTW, if you use diamond paste etc. the lap should be softer than the thing you are lapping so the diamonds will embed themselves in the lap and not the tool... soft cast iron, copper or something like that (a lot of the woodworking places sell cast iron lapping plates for about $17 but the surface isn't perfectly smooth)

Fred is right about the DMT & Eze-laps... when new they seem very aggressive and leave a rougher finish but as you use them, you knock off the surface diamonds (especially if you push hard) and they become a far less aggressive. Some people consider them to have been worn out, but I look at it as breaking them in... they will become slower, but leave a finer finish. They do have their problems though, particularly when you are using them to polish.... sometimes, somewhere, lost of the surface of one of those plates, there will be one or two bigger diamonds (or perhaps sticking up a lot higher than the rest). This can put some honking big scratches in along with your nice even pattern of little scratches (for sharpening, this would just give an edge a bit of thooth, but for polishing it is better to use paste or spray and clean things hospital clean between grits)

[KneeKnocks]

Yuzuha,

Please allow me to rather belatedly add my welcome to these forums. Like other posters above, I am most impressed with your detailed and precise descriptions and explanations. Yes, the wealth of practical experience that Fred and others bring to these forums is extremely valuable and informative, but your scientific explanations certainly add a new dimension to the discussion. I look forward to reading your future posts, especially when the discussions turn to the metallurgy of cutlery steels.

Again, a most warm welcome!

[mikemac]

great information all...and if the diamond producing folks don't agree on the "micron = mesh" equation, how would any of it translate to me or the world of grits? Unless grits = mesh,(but grits = grits /ubbthreads/images/graemlins/grin.gif) and than why wouldn't they just say so...but I can and have used the dmt to 'true' up my King's, and to do some 'rough'

[Scott]

Here is some additional information regarding grits, sizes, and cutting:

http://users.ameritech.net/knives/speed.htm
http://users.ameritech.net/sharpening/mohs.htm
http://users.ameritech.net/knives/grits.htm

Hope this helps. /ubbthreads/images/graemlins/grin.gif

Scott

[Grouch]

I spent ~5 years in the particle sizing business. The difficulty in measuring most particles is they're not spherical. A long needle can pass through a narrow mesh. There are many different (non-equivalent) ways to describe the size of a non-spherical particle. Also, there are many techniques to measure the size of small non-spherical particles. Each technique "favors" a different size characteristic: volume, surface area, maximum diameter, minimun diameter, cross-sectional area, etc.. Additionally, the variance of the particle sizes in the substrate might be difficult to constrain.

[Scott]

Grouch,

It reminds me of something I read once about the Shapton 30K stone. I believe it was attributed to Harrelson Stanley (the guy that does their sharpening DVD and demos around the country). When asked why the 30K stone was so expensive ($635 from Shapton) he apparently said that the cost was so high because of the difficulty in making the stone. He said something like, "Imagine a room filled with a fine haze of smoke (to represent the size of the particles in the stone). Now imagine trying to take all that smoke and put it into one place that is 'stone sized' and you will have an idea how difficult it is to make this stone."

I would guess that would put that stone's particle size down around .1 micron or less... on average.

I really had not thought about the difficulty in measuring size due to shapes, but can see that would be very difficult. I can just imagine the issues with particle size in a 30K stone. Wow! /ubbthreads/images/graemlins/shocked.gif

Scott

[yuzuha]

I think the 30k grit stone is more like 1/2 micron since their 15k stone is about 1 micron (.96). They may have been being a little grandiose talking about a room full of smoke (generally 1 micron and under). Maybe they have some problems with that fine an abrasive wanting to float on the resin they use or something, or maybe they just don't have any competition other than expensive natural stones. Shinichi Watanabi (yeah, I bought some knives and a natural stone from him so I had to bug him with questions about Uchigumori and awase suita stones etc. He said that the suita worked better on hard steel but Uchigumori were usually of higher quality, but you can't really tell about a stone without using it. He also mentioned that when he uses up the 20k grit natural stone he inherited, that he will not be able to replace it even for $10,000 (a good reason to charge extra for his togidashi polishing.)

Graves company sells Linde A and B (.3 micron and .05 micron aluminum oxide) as well as diamond sprays up to 200000 mesh (.1 micron) as well as chrome oxide powder (don't mention a size on this but probably .5 micron like Hand America's) http://www.gravescompany.com/polishin.htm (lapidary suppliers deal with lots of fine abrasives so their prices are generally good, though things like cerium oxide, tin oxide and titanium dioxide are not any good for knife polishing)

Scott, nice idea about using a 2x4. I generally just plop one of those metal/rubber stone holders, that sell anywhere from $10 to $18 depending on where you buy it, next to my sink. You might be interested in seeing what sword polishers use as a holder though. http://www.ghost-cat.com/polishing.htm (some nice pics of the effects of various stones too) The traditional holder isn't cheap http://www.shadowofleaves.com/polishing_equipment.htm

[Grouch]

While using a grit size as a qualitative measure of an abrasive's abilities is OK, one should know that there is a range of sizes incorporated within the abrasive. The size reported is some statistic (mean, mode, median) for the distribution of grits making up the abrasive. As grits aren't round, the size may be:
maximal diameter, minimal diameter, 2[3 Volume/(4pi)]^1/3, 2[SurfaceArea/(4pi)]^1/2, etc.
Many fine particle measurements are not performed optically. Some other attribute is measured that correlates to size. So, take the given grit size with a grain of salt.

[Scott]

Yuzuha,

[ QUOTE ]
I think the 30k grit stone is more like 1/2 micron since their 15k stone is about 1 micron (.96). They may have been being a little grandiose talking about a room full of smoke (generally 1 micron and under). Maybe they have some problems with that fine an abrasive wanting to float on the resin they use or something, or maybe they just don't have any competition other than expensive natural stones.

[/ QUOTE ]

The one reason I believe that it could be down to .1 micron (forgive me grouch, but I use this for illustration) is because the Japanese grit system does not appear to be linear. Especially as you get to the higher grits. Please see this site:

http://users.ameritech.net/knives/grits.htm

and

http://208.63.68.209/SharpenGuide.htm#Grit

However, there is, obviously much room for fudging if they care to do so. I mean, who is going to check to see if they are telling the truth? Or, probably more accurately, who is going to test to tell which truth they are telling (in reference to grouch's posts on how to measure size).

[ QUOTE ]
Shinichi Watanabi (yeah, I bought some knives and a natural stone from him so I had to bug him with questions about Uchigumori and awase suita stones etc. He said that the suita worked better on hard steel but Uchigumori were usually of higher quality, but you can't really tell about a stone without using it. He also mentioned that when he uses up the 20k grit natural stone he inherited, that he will not be able to replace it even for $10,000 (a good reason to charge extra for his togidashi polishing.)

[/ QUOTE ]

Yeah, I had noticed that issue with his natural stone. I can see that he guards it well and justifiably so. I wonder how this stone would compare to his stone?

http://shop.niimi.okayama.jp/kajiya/en/shop_e/toishi_e/okudosui_e.html

[ QUOTE ]
Graves company sells Linde A and B (.3 micron and .05 micron aluminum oxide) as well as diamond sprays up to 200000 mesh (.1 micron) as well as chrome oxide powder (don't mention a size on this but probably .5 micron like Hand America's) http://www.gravescompany.com/polishin.htm (lapidary suppliers deal with lots of fine abrasives so their prices are generally good, though things like cerium oxide, tin oxide and titanium dioxide are not any good for knife polishing)

[/ QUOTE ]

I had seen some powders in this range before. My problem now is how to use them. By this I mean that I am getting much sharper results by using a high-grit stone than I did when using a leather strop. The leather strop has actually dulled the edge the last couple times I have used it. I guess that I would have to use my granite surface plate or an equivalent to be able to take advantage of these powders. Because of this, I'll wait until another time to test this stuff... /ubbthreads/images/graemlins/smile.gif

[ QUOTE ]
Scott, nice idea about using a 2x4. I generally just plop one of those metal/rubber stone holders, that sell anywhere from $10 to $18 depending on where you buy it, next to my sink. You might be interested in seeing what sword polishers use as a holder though. http://www.ghost-cat.com/polishing.htm (some nice pics of the effects of various stones too) The traditional holder isn't cheap http://www.shadowofleaves.com/polishing_equipment.htm

[/ QUOTE ]

Those links to the sword polishing stuff is fascinating. I remember when I was much younger and heavily into martial arts and read about the relationships that practitioners had with their swords. I respected their dedication (obsessiveness), but never really began to comprehend it until I started sharpening my knives... /ubbthreads/images/graemlins/laugh.gif

As I have mentioned here before, I have found that sharpening my knives to be a zen-like experience. For me it is very relaxing. On the other hand, to do it as a business would likely ruin it for me. /ubbthreads/images/graemlins/crazy.gif

As for the board, I cannot take credit for it. I think I mentioned that I got it from Murray Carter's DVD. In another post (http://216.91.137.210/ubbthreads/showflat.php/Cat/0/Number/1948/an/0/page/0/gonew/1) , I have added some refinements, but the basic idea is sound and simple.

I also have one of the stone holders and even use it, though it is not required with Carter's setup (I should also mention using a towel under the stone is hardly unique with Japanese sharpeners). My purpose for using it is to suspend the stone over the water so that dripping water (and slurry) do not get all over the place. After cleaning up that mess a few times both I and my wife were tired of it, thus prompting my search for a better solution.

Also, I sharpen my knives while I watch TV. I cannot do this at the kitchen sink (especially with my (5 year old) 60" rear projection TV). /ubbthreads/images/graemlins/grin.gif

Scott

[Scott]

Grouch,

Based on what you say about the difficulty in measuring the actual grit at these sizes, what would they use instead? Something like measuring the scratch sizes and interpolate the actual size from that?

Oh my aching head... /ubbthreads/images/graemlins/grin.gif

Scott

[Grouch]

Scott,
There are myriad techniques for measuring the size of fine particles: microscopy, time-of-flight, particle counters, mesh separation, electrolytic, etc( e.g., see this page (http://www.bic.com/PDFs/AGuidetoChoosingaParticleSizer.pdf) ). What the stone manufacturers (or their suppliers) utilize is anyone's guess.

[Scott]

Grouch,

Way cool! /ubbthreads/images/graemlins/cool.gif The techno-nerd in me just loves this kind of stuff... /ubbthreads/images/graemlins/grin.gif

Thanks!

Scott

[yuzuha]

[ QUOTE ]


The one reason I believe that it could be down to .1 micron (forgive me grouch, but I use this for illustration) is because the Japanese grit system does not appear to be linear. Especially as you get to the higher grits. Please see this site:

[/ QUOTE ]

No, but the sites you mention do not support that either... diamond mesh seems to jump higher than JIS grit and .1 micron diamond is listed as 240,000 mesh 1/2 micron is 60,000 mesh, and 1 micron is 14,000 mesh.

Now Shapton lists their K0705 stone as .96 micron (nearly 1) and the Japanese site says the 0705 model stone (actually embossed on the stone itself) is 12,000 grit and the US site says it is 15,000 (which corresponds much more closely with the diamond grit mesh size, so it seems the Japanese site is understating a bit and the US site is maybe closer, but both list the purple as 30,000.) So, I still think their 30k stone is closer to .5-.6 microns

[ QUOTE ]

Yeah, I had noticed that issue with his natural stone. I can see that he guards it well and justifiably so. I wonder how this stone would compare to his stone?

http://shop.niimi.okayama.jp/kajiya/en/shop_e/toishi_e/okudosui_e.html

[/ QUOTE ]
Yes, I showed him that 1.5 million yen stone and that is what prompted his comment about not being able to replace his stone. So, he obviously doesn't consider even that one to be up to the level of his stone.

[ QUOTE ]


I had seen some powders in this range before. My problem now is how to use them. By this I mean that I am getting much sharper results by using a high-grit stone than I did when using a leather strop. The leather strop has actually dulled the edge the last couple times I have used it. I guess that I would have to use my granite surface plate or an equivalent to be able to take advantage of these powders. Because of this, I'll wait until another time to test this stuff... /ubbthreads/images/graemlins/smile.gif

[/ QUOTE ]
put it on a sheet of plastic film, like 3M uses for their micro-finishing film, on your surface plate. Lee Valley has plastic laminate sheets just for this: plastic sheets (http://www.leevalley.com/wood/page.aspx?c=2&p=33017&cat=1,43072) though you could probably just use wet artist's acetate.

Obviously it depends on blade geometry, but I have not had trouble stropping my pocket knife or other small knives that I bother to strop. But then, I do not try to strop the actual bevel (I am aware that leather is somewhat pliable so never try to tilt the blade 'til it can get a bite and then draw back, unless I am intentionally trying to convex the edge), I just lay the blade flat on the strop (which is supported by an iron plate) and polish the side of the blade, letting the leather itself spring up after the blade passes and clip the bevel as it returns to its normal shape (doesn't look like you are accomplishing anything but polishing the side of the blade, but, unless you have a huge bevel, it really does spring back and just graze the edge). Been using water soluble 1/2 micron diamond paste instead of buffing compound (unless it specifically states .5 micron green honing compound, those green rouge bars are a lot coarser than that... up to 3 microns, so avoid them)


[ QUOTE ]
As I have mentioned here before, I have found that sharpening my knives to be a zen-like experience. For me it is very relaxing. On the other hand, to do it as a business would likely ruin it for me. /ubbthreads/images/graemlins/crazy.gif

[/ QUOTE ]
Also guilty! /ubbthreads/images/graemlins/crazy.gif

[ QUOTE ]
Also, I sharpen my knives while I watch TV. I cannot do this at the kitchen sink (especially with my (5 year old) 60" rear projection TV). /ubbthreads/images/graemlins/grin.gif


[/ QUOTE ]

Again, guilty as charged. I often watch foreign films and even with a wide screen tv, I can't read the subs from the sofa, so 9 times out of ten, I'll just plop down on the floor in front of the tv like I did when I was a kid. I'm so used to it that I even do it with regular tv programs.... Often with a couple of ceramic stones, my holder, a bottle of windex (the ammonia kind, not the vinegar), a roll of paper towels, and a plastic bag to stick under things to keep the mess off the floor. ROFL, it could be that my knives are entirely too sharp, all because sharpening is relaxing /ubbthreads/images/graemlins/wink.gif

[dbtoe]

If the Shapton stones are really a plastic type stone do you think they could be used dry? Has anyone tried useing them dry? I wonder if they would ware the same or give the same finish. Does anyone have any reason why they couldn't be used dry?

[blwchef]

I would say that there would be too much friction and that would cause heat to build up quickly and damage the blade.
Just a hunch.

[Fred]

Based on comments I've read on other forums (fora?) I've tried every stone I have dry. Dry is good for diamond or ceramic (the white industrial ceramic sticks, I mean.) Otherwise don't use them dry. I think the people on the other forums are all wet. /ubbthreads/images/graemlins/smile.gif

[blwchef]

Well you learn some thing new ever day here. That's why I love it.

[yuzuha]

[ QUOTE ]
If the Shapton stones are really a plastic type stone do you think they could be used dry? Has anyone tried useing them dry? I wonder if they would ware the same or give the same finish. Does anyone have any reason why they couldn't be used dry?

[/ QUOTE ]

No, I agree with Fred. I tried my Shapton without water once and it was like drawing on it with a crayon, just loaded up like crazy (but then mine is also a super fine grit stones and they tend to load anyway).

Oh, also be careful in the kitchen! I got a drop of hot garlic butter on my Shapton and nothing gets it out... tried lapping it off, 30% ammonia, soaking, Dawn dish soap, lighter fluid, Goo Gone and freon circuit-board degreaser (yeah, I dabbled in electronics once... this is the ozone safe stuff and won't hurt plastics). Nothing worked.

So, now I have this little round 2-3mm butter spot that just won't go away. It isn't a huge problem since it doesn't make the stone unusable and is off in a corner anyway, but it is a trifle annoying since that one spot loads up as badly as a dry stone and I can feel it sort of bind a little when a blade passes over it.

[Fred]

Now how would I have guessed you would have a ready supply of circuit board degreaser? /ubbthreads/images/graemlins/wink.gif

[barbouni]

I thought I would bump this classic. There is so much good stuff in here for new members.

[TATATA]

Long time no see!
I think that a natural whetstone is effective in carbon steel.I tested many natural whetstones with various steel materials.An artificial whetstone is very effective in stainless steel material.
If a natural whetstone is used for stainless steel, the thing of a rude particle will be good.
Aoto, Suita, and Akamon are famous as a medium whetstone in Japan.Akamon is already a natural whetstone with difficult acquisition.
I investigated the relation between edged tool steel materials and a whetstone in detail. If the edged tool steel materials which you have are taught to me, I will be able to recommend the optimal whetstone.
Cutting quality goes up by uniting a whetstone with edged tool steel materials considerably.

I heard the rumor referred to as that a good natural whetstone is produced in Australia. My acquaintance said that they could be found on the seashore.

As for WebSite which I manufacture, the dialect of Japan is contained for a while. :-)
I am going to distribute various information by this forum.
Thank you for your consideration.

[Fred]

Welcome back, Tatata. I was told that the Australian stones were imported from Japan and then cut and packaged in Australia. Is this not true?

[TATATA]

I asked the natural whetstone production company president by telephone. In their association, it was said that export was not performed in the state of an ore.
In Japan, a natural whetstone is in very few states.
Exporting to overseas commercially is impossible.
If packed in Australia, it may be [the product] re-packed in the whetstone fabricated in Japan.

[Fred]

That is interesting. Thank you. I was under the impression that my stone is from Japan but, apparently, it is from Australia. Now I will have to get another for a test.

Another question, please. How do Japanese cooks use the miroshi deba? Is it used for chopping food?

[TATATA]

Mioroshi Deba is used when cooking a fish.
Mi= body Oroshi = cook fish. Deba=Deba.
It is Deba of the exclusive use which cooks a fish.
It is Deba thinner than ordinary Deba.
Thin Deba is sharp and an edge goes into a fish.
Deba cuts off the head of a fish and MioroshiDeba makes fillet steak.
MioroshiDeba is a single edge.

[Fred]

Then the mioroshi deba is the filet knife. Thank you.

[yuzuha]

Ohayo Tatata ^-^/" Nice to see you again!

[ QUOTE ]
Long time no see!
I think that a natural whetstone is effective in carbon steel.I tested many natural whetstones with various steel materials.An artificial whetstone is very effective in stainless steel material.
If a natural whetstone is used for stainless steel, the thing of a rude particle will be good.

[/ QUOTE ]

I have also found this to be true. "Shaputon" kuromaku stones seem very good on stainless steel, but natural stones often leave a dark smoke-like haze on the steel (thinking that stone particles get caught in the tiny pores of the steel and cause it to look dirty), but I like the polish that natural stones leave on carbon steel.

I can not read Nihongo, but have found this site very useful http://www015.upp.so-net.ne.jp/toishi-erabi/index.html even if machine translators like http://www.nifty.com/globalgate/ and http://babelfish.altavista.com/ turn Japanese into some very strange English! ^0^ It is fun to look at things like the stones on pages 278-284 on web sites like this http://homepage1.nifty.com/shincoo/c1-vbk-chuubou-1-mokuji.htm or these http://homepage2.nifty.com/s-kawai/tennen-toisi_hanbai.html and even sword stones like they sell here http://www.namikawa-ltd.co.jp/index.html

I wish I had a relative in Japan who could buy some of these things for me, but then I would probably spend way too much money! ^0^

[TATATA]

Thank you for your message.
Yes, "Shaputon" whetstone is congenial to stainless steel.
I am the same opinion as you!!

I also like the gloss which the natural whetstone has.
Furthermore, he likes the smell when polishing by the natural whetstone. /ubbthreads/images/graemlins/grin.gif It is the scent to relax.

The gloss can be made from a Uchigumori whetstone.
A Uchigumori whetstone is used for makeup sharping of a Japanese sword. It emphasizes Hamon.

If you reach to an extreme of a Japanese kitchen knife, you will think that this set is cheap.
[Japanese Sword polising kit]
http://www.namikawa-ltd.co.jp/english/index.html

Keep polising!! /ubbthreads/images/graemlins/smirk.gif