Ceramic vs Diamond vs Synthetic vs Natural Sharpening stones

J

JD Spydo

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Nov 20, 2004
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I've been a knife user and collector for many, many years now but I'm also just as much of a collector of Sharpening Tools as well. I have quite an array of sharpening stones. I have a complete set of Spyderco's great 302 Benchstones that I love to use and get great results with. But Spyderco's stones are the only ceramic sharpening stones I own so in that category I have nothing to really compare them too. However I've been so satisfied with them that I haven't had the desire to check out other Ceramic stones. But I would like to hear some feedback about ceramic stones made by other companies as well.

In the Diamond stone category I have stones made by Norton, DMT and 3M. I've had good overall results with the diamond stones I've acrued over the years>> but I've found my 3M diamond sharpening tools to be the best I've used up till now. I've heard great things about Atoma diamond stones but I've yet to try them out. Also if there are any other diamond stones that are good I would like to hear about them as well.

I also have some Norton India and Norton Waterstones>> I also have some of Norton's synthetic stones. I consider Silicon Carbide, Aluminum Oxide and CBN in the synthetic ( man made) category. I also have a decent selection of Natural stones like "novaculite" (Arkansas Stones) and I have one natural stone put out years ago by Norton called the "Queer Creek" stone which was supposed to be a natural stone found in river and creek beds. I've also heard good things about Coticule (Belgium Razor Stones.

I would like to discuss all of these categories of sharpening stones and find out which ones you guys all like or don't like. I put up ceramic stones first because I would like to know more about them and how Spyderco's compare with other ceramic stones on the market. If there are types of sharpening stones I failed to mention then by all means I want to know about them too.
 
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I guess ceramic stones like the Naniwa's are the top choice for straight razors, not sure about knives though. They come highly recommended for razor honing. I guess Shapton's are also very good for razors but again, not sure about knives.

For knives I don't use anything over something like an extra fine DMT so 1200 grit. Razors guys go as high as 20k or more!

I will follow this thread as I think it will be great reading! Thx.
 
Spyderco ceramics are the best on the market in terms of ceramic stones, don't waste your time or money trying to find anything better you won't .

Sharpening is 90% technique 10% equipment . The steels.you own and sharpen dictate the stones you buy.

IMHO a diamond plate and the medium spyderco bench stone can get you a ridiculous edge on any knife you could buy.
 
sir_mike said:
I guess ceramic stones like the Naniwa's are the top choice for straight razors, not sure about knives though. They come highly recommended for razor honing. I guess Shapton's are also very good for razors but again, not sure about knives.

For knives I don't use anything over something like an extra fine DMT so 1200 grit. Razors guys go as high as 20k or more!

I will follow this thread as I think it will be great reading! Thx.
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Hey thanks for your input "Sir Mike" because I'm also a member of a Straight Razor Forum known as www.straightrazorplace.com>> I joined it not because I'm all that much of a straight razor fan per se like I am with knives but because I'm intrigued with the interesting variety of sharpening equipment they use for straight razors. Now don't forget that Spyderco's "ultra-fine" 302 benchstone is also known to be a great sharpening stone for straight razors. I believe I remember Sal Glesser himself touting the Spyderco 302 Ultra-Fine stone as being an ideal tool to sharpen straight razors with.

But believe me it's also a great finishing tool for many different types of knife blade steel as well. The Spyderco Ultra-Fine stone does an extremely good job on my M390 Military model as well as quite a few other favorite Spyderco blades I use. I'm very glad you mentioned "Naniwa" because now I do remember someone else saying that they made some really good quality ceramic sharpening stones. I also seem to remember another company and I believe their name was "Global" if my memory serves me well also is known for good quality ceramic sharpening tools. Now I have two small ceramic sharpening devices made by DMT and they seem to be good quality as well. But I don't think DMT makes ceramic benchstones.
 
Spartan00 said:
Spyderco ceramics are the best on the market in terms of ceramic stones, don't waste your time or money trying to find anything better you won't .

Sharpening is 90% technique 10% equipment . The steels.you own and sharpen dictate the stones you buy.

IMHO a diamond plate and the medium spyderco bench stone can get you a ridiculous edge on any knife you could buy.
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I have virtually no doubt that you're 100% correct with that "Spartan". Because I've noticed that most retailers and vendors who sell sharpening tools usually only sell Spyderco ceramic stones. And all the time I've been on this Forum and Spyderco's own Forum I've yet to hear anyone brag about any other ceramic sharpening tools other than Spyderco.

That's one of the main reasons I'm such a fan of Spyderco's is that they put high quality is just about everything they do. I've yet to try a set of the CBN stones that Spyderco has recently made available for Spyderco's 204 Sharpmaker but they are next on my list of sharpening tools to buy. I don't know what classification or category they fall in>> maybe they are regarded as synthetic or man made stones?
 
As far as I know the spyderco bench stones are unique. You can get ceramic water stones and ceramic sticks .

The sticks are all a little coarser than the spyderco grits .I've been using an UF bench stone for years . Back when there were claims you could lap it and turn it into a shapton lol.

I bought it and lapped the hell out of one side ,it was pretty flat basically I just removed the tool marks ,but it did increase the Polish the stone gives ,the cost was 2 diamond plates IIRC and a lot of man hours ,I wouldn't do it again lol.

On my medium spyderco one side is worn smoother than the other so I'll do passes on the rough side of the medium then the worn side ,same with UF and finish with the side I had "lapped" .

If I do my parts on the lower grits to remove the scratch pattern then the spyderco will put a mirror polish. From a polishing only look the UF polishes just as well if not better than my naniwa 10k super stone .

Thing about stones too is water you get you need the set . If you want Waterstones buy the same brand or your going to shoot yourself in the foot .

I have the Norton 1k/4k and I'm not a fan for knives . It's personal preference I just don't like the feel.of the stones and I can get better edges off other stones .

Coarse stones I like a softer Waterstone for the mud . As I get higher in the grits though I like harder stones. I've had several edges ruined off soft Hugh frit water stones by digging into the edge .

If you get a softer finishing WaterstoNE be careful. I tend to do stropping strokes only on the softer Waterstones.
 
JD Spydo said:
Hey thanks for your input "Sir Mike" because I'm also a member of a Straight Razor Forum known as www.straightrazorplace.com>> I joined it not because I'm all that much of a straight razor fan per se like I am with knives but because I'm intrigued with the interesting variety of sharpening equipment they use for straight razors. Now don't forget that Spyderco's "ultra-fine" 302 benchstone is also known to be a great sharpening stone for straight razors. I believe I remember Sal Glesser himself touting the Spyderco 302 Ultra-Fine stone as being an ideal tool to sharpen straight razors with.

But believe me it's also a great finishing tool for many different types of knife blade steel as well. The Spyderco Ultra-Fine stone does an extremely good job on my M390 Military model as well as quite a few other favorite Spyderco blades I use. I'm very glad you mentioned "Naniwa" because now I do remember someone else saying that they made some really good quality ceramic sharpening stones. I also seem to remember another company and I believe their name was "Global" if my memory serves me well also is known for good quality ceramic sharpening tools. Now I have two small ceramic sharpening devices made by DMT and they seem to be good quality as well. But I don't think DMT makes ceramic benchstones.
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I remember some chat about using the 302UF for razors and I think I asked that question in the Spyderco forum. Unfortunately, I could only find one person, Sal saying that he uses his ceramics for razors. Most everyone else said they would NOT use them, not fine enough I guess. IDK and dont have a 302uf to try out on a razor to test so I will have to stick with Naniwa's and sometime I will try a jnat for a finisher. Another good finisher for razors I have heard is the ILR 12-15k stone.

I should add that I haven't honed a razor yet, just used an 8k and ILR to refresh one. I will begin that process shortly though! :)
 
I sold off all my waterstones, threw the Nortons in the garden shed , and for the last few years all I used is Eze-Lap and DMT diamond stones/rods and Spyderco ceramics ( DC4 and Model "M " Eze-Lap for field use.) Any type steel is handled by those , the cleanup is easy . the stones last a long time , and the results are impressive.
 
I did nearly the same as hiwa.... and never looked back.

Eze-Lap 600/1200 and Spyderco ceramic for all my knives including pricey Japanese kitchen cutlery.
 
I have quite a collection of stones. At last count I believe it was near a hundred. They all have their place and uses. My collection is not quite evenly split with the natural stones outnumbering the synthetic about 2 to 1.

I have a Spydie Ultra Fine that is easily capable of putting a great edge on a razor. I left one side with the factory "swirled" finish for knives and flattened/conditioned the opposite side for razor use. Other outstanding stones for finishing razors are Arkansas Black & Translucent stones (these need proper prep to give the most comfortable edges), Japanese natural stones, Thuringian stones (same as Eschers), coticules and the Suehiro Gokumyo 20k. I tested an ILR 12-15k and didn't care for it that much. Quite a few notable razor guys have found the same result. I could shave with edges from it but it wasn't on par with the better stones for me. And I tried about eight different methods IIRC to try to eek every last bit out of it. Plenty keen edge but the against the grain shave wasn't comfortable for me.

Diamond stones are extremely useful, I use them often. I've got quite a few DMT plates as well as 3 Atomas. The Atomas have a slight edge for lapping/flattening stones, but I don't like them for honing - the feel of the interrupted surface is like fingernails on a chalkboard for me. I've never tried a 3M diamond plate JD, how do they compare to the DMTs?
 
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sir_mike said:
I guess ceramic stones like the Naniwa's are the top choice for straight razors, not sure about knives though. They come highly recommended for razor honing. I guess Shapton's are also very good for razors but again, not sure about knives.

For knives I don't use anything over something like an extra fine DMT so 1200 grit. Razors guys go as high as 20k or more!

I will follow this thread as I think it will be great reading! Thx.
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Naniwa makes resin bonded (super stones) and magnesium bonded (Chosera) stones, their new ceramics are just now becoming available but they are not sold in many places.
 
Jason B. said:
Naniwa makes resin bonded (super stones) and magnesium bonded (Chosera) stones, their new ceramics are just now becoming available but they are not sold in many places.
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That's interesting Jason B. because from what a good friend told me there is a really broad definition of the word "ceramic". And I got a feeling that a lot of these newer stones I'm hearing a lot about would probably fall under the category of "ceramic".

I'm also wondering at this point if a ceramic stone and a sintered material might also be one in the same? The only thing I don't like about ceramic sharpening stones like the ones Spyderco sells is that they load up fast and I usually clean mine after about every 2 knife sharpenings. I know that there are many of you who may think that's overkill but if I go more than 2 knife blades on my 204 Sharpmaker stones I can sense that they no longer have that uniform bite that I get with a really clean ceramic stone. And I find with that uniform bite that I can feel that the edge really gets super sharp when keeping the stone very clean.
 
Ceramic waterstones and Spyderco ceramics are nothing alike. Ceramic waterstones are ceramic abrasive in a binder and can rage from very hard stones to very soft stones with various wear rates and cutting speeds. Spyderco ceramics are Kiln fired alumina, they are pure abrasive that is sintered together to form a very dense and hard material. Spyderco ceramics are the most recognizable type of "ceramic" but you are correct in saying that Ceramic can be defined in many ways.

Ceramic waterstones like Shapton, Bester/Beston, Suehiro Cerax, Naniwa Gouken, and probably a few others I am forgetting are the stones to look at for "ceramic" waterstones. The advantage to these stones are typically all in the cutting speed and ability to handle high alloy steels.
 
Knowing that metals and materials like Tungsten carbide and other exotic materials that are known as "Sintered" materials>> I've wondered if many of those types of materials that can also be used as super hard abrasives? With the technology expanding at such an exponential rate I think it's going to be very interesting to see what new innovations occur in the area of abrasive materials. Now when they rate abrasives on the "Moh's Hardness Scale" it starts at the top with "diamond" being right up at number 10>> because at this time diamond is the hardest known substance here on the earth. It's much harder than any steel alloy or even ceramic too for that matter.

I've often wondered why super hard materials like Tungsten Carbide or other super hard materials that you never hear of being used as abrasives. I'm also wondering what all of the nanotech sciences are going to produce in the area of abrasives as well. I also think we will soon be seeing ceramics just about as hard as diamond before too long. Just in the area of conventional sandpaper there has been huge improvements.
 
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Although tungsten is hard it's not harder than most of the abrasives used in stones, it's actually much softer than even aluminum oxide. You should also be looking at the Knoop hardness scale, it's more accurate.
 
Shame Spyderco don't make their stones a bit bigger. I have a couple of now old and worn waterstones, but I want to go wider than 2".
 
Hm, JD mentioned tungsten carbide, not tungsten. Totally different animal. Tungsten carbide will easily cut hardened steel, and is used to do so all the time in every machine shop in the world. It's usually in the neighborhood of 70+Rc. It probably would need to be textured to effectively cut steel though, and might wear out the texture cutting much steel in the neighborhood of 60+Rc - especially if the steel contains many carbides.
 
Tungsten Carbide- Knoop hardness 1400-1800

Aluminum Oxide- Knoop hardness 2100

With aluminum oxide quickly becoming inferior in the world of sharpening with the vastly increasing number of carbide saturated steels why would you want to downgrade to a material that would be less effective?

I'm sure it would be a costly adventure too, making molds for individual grit sizes then mass producing it one single abrasive at a time.
 
Right, but the binder in AlOx stones won't hold up like a solid piece of tungsten carbide. Fred Rowe is using tungsten carbide in his pull through sharpener and it seems to hold up fine there. It's also used in just about every pull-through sharpener there is and keeps on cutting in those as well. (Though of course leaves a nasty ragged edge because it's cutting huge chunks out of the blade). It would be ready enough to find a piece of TC that would do the trick, no need to have something custom made. There are all sorts of TC blanks made by the thousand sold in every industrial supply catalog, as well as plenty of TC supply specialists that keep different sized blanks on hand for custom tooling.

I'm not saying it will work well or won't - just that there's no telling how well it would work without trying it.
 
Tungsten carbide (WC) sharpeners and other so-called 'solid' carbide-tipped tools utilize what's called 'cemented carbide', which is an engineered material and only durable because of a binder. The grains of pure WC are bound by a cobalt (or nickel) metal binder; therefore a carbide sharpening insert isn't actually a 'solid piece' of pure tungsten carbide. The metal binder is what lends toughness to the carbide insert or tool tip, and therefore gives it resistance to breaking down or chipping. Raw WC, such as found in the combining of elemental tungsten and carbon in a knife steel alloy, has no tough engineered binder and isn't really all that hard by comparison to AlOx or other abrasives as previously mentioned, though it's still 2X-3X as hard as most hardened cutlery steels (steel is usually Knoop ~600-800). In it's raw form with no binder to stabilize it, WC is very brittle and wouldn't hold up in the same manner as with the cemented carbide in WC sharpeners. I'm guessing the main attractiveness of cemented-carbide WC sharpeners and other cutting tools is mainly in their low cost and relatively high toughness, and less in the hardness of the abrasive WC grains themselves, which are hard enough to do the jobs for which the tool is engineered, but nothing special beyond that.

There are apparently some highly engineered versions of pure WC ceramics, produced by a process called 'high-temperature hot isostatic processing', which can attain hardness similar to aluminum oxide (~2100 Knoop). One application of it is apparently for wear-resistant abrasive water jet nozzles. But even at that hardness, it's still only as hard as AlOx, but no harder, and probably very expensive by comparison to simple aluminum oxide abrasives, which are ubiquitous and almost dirt-cheap at times. So, in spite of all the advanced engineering, it doesn't seem like WC would be much of an upgrade as a sharpening abrasive, especially as compared to the AlOx & SiC (~2600 Knoop) abrasives already available for little money.


David
 
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