Fällkniven gray vs Spyderco medium ceramics?

[Mr.Wizard]

I have 15 µm as the approximate apparent coarseness of the Spyderco medium ceramic and Fällkniven rates their gray ceramic with the same value. Does anyone have both to compare?

 

[Obsessed with Edges]

I have examples of both. Mine are older examples, with my Spydercos (two DoubleStuff hones, one bench hone, and a Sharpmaker with it's standard medium & fine rods) dating back 10-20 years or more, and my Fallkniven DC4 dating back maybe 10 years or so.

The big difference between them has always been more about factory surface finishing (at least), rather than actual grit size. This has always been the case with Spyderco's sintered ceramics, with all of them (medium, fine and ultrafine) being produced using the same alumina grit in the 15-25 micron size ballpark, per Sal Glesser's own comments on the Spyderco forum (excerpt of that below).

"All of the ceramics use the same micron size (15-25). the different grits are created by different carriers, different firing techniques and diamond surface grinding."

Based on my own experience with the Fallkniven, which came from the factory with a VERY coarse and/or irregular, bumpy surface finish, and also based on posts I've read here on the forum from others reporting a lot of variation in surface characteristics, Fallkniven's surface finishing seems to be the overwhelming dominant influence on how the hones perform. It seems impossible to know how they'd compare based only upon the stated grit spec for each.

Spyderco seems to have been much more consistent about maintaining predictable behavior in all their hones, across each respective grit rating (medium, fine, uf) and over a span of many years. But based on everything I've read & experienced with Fallkniven's medium ceramic, it seems to be very much a luck-of-the-draw determination. Always a big question mark about how each new hone coming from the factory will perform. I still don't have a clear picture of what they're supposed to be, by original design.

 

[Mr.Wizard]

Obsessed with Edges do you know if the white "super fine ceramic" (in CC4) is similarly inconsistent?

 

[Obsessed with Edges]

Obsessed with Edges do you know if the white "super fine ceramic" (in CC4) is similarly inconsistent?

Never tried that one. I don't recall seeing any posts here on the forum either, about issues with that one. All of the issues I'm aware of were related to the grey ceramic from Fallkniven. I don't know how long the white has been around either. It may be I haven't heard of any issues with it, if it's a relatively new offering from them.

 

[353]

Fallknive is A LOT coarser IMO. I'm not even sure they are made of the same stuff.

 

[Papilio]

Actually I have a DC4, a CC4 and a DC521.
Let us begin with the dark ceramic (15µ). My DC4 is about 10 years old. And in the meanwhile the ceramic is very smooth and fine. But I refinished this hone, it wasn't only a natural process.
Both the CC4 and the DC521 are quite new. Their finish is a lot rougher than a Spyderco Medium. Nonetheless I would say that even the refinished DC4 is more aggressive than the Sypderco. The surface finish - as long as we talk about the dark ceramic side - does not have any kind of quality issues. Even and not bumby. To be fair: I had to claim one CC4 because that stone did have a bad surface finish.
Compared to a Spyderco Medium (sold this stone) the dark ceramic works faster. The Spyderco seems to be finer and more even or less "spongy".
Fallkniven uses synthetic sapphires.

The fine white ceramic of a Fallkniven stone leaves a good edge. But compared to a Spyderco Fine (I had one of this Bench Stones) it is not of the same quality, I would say. The surface is coarser and a lot more uneven. Some micro bumps or grooves are visible, especially after sharpening (swarf). It is not very distinctive when you use your finger. But visible by naked eye.
I have no idea what kind of material they use for the white ceramic.
For years the fine white ceramic has been rated as "ultra-fine". Nowadays Fallkniven says 9µ. This rating is disappointing. A Spyderco Fine would be a lot finer then.
Maybe the white side gets finer. Up to now I would say that Spyderco is finer.

 

[FortyTwoBlades]

They all use synthetic sapphires (aluminum oxide) and they all have a mix of grain sizes averaging 15µ but those are not the important part here. Abrasives in general rely on more than just the grit size to affect the finish produced and relative cut speed, and sintered ceramics even more so.

Sintered ceramics are binderless and are basically like synthetic sedimentary rock, with the enormous heat and pressure used in their creation causing the grains to fuse with one another. This not only makes for a very hard bond, but the grains are in a range of sizes to make them easier to fuse--if they were all one size they wouldn't want to stick together so readily. However the final product's cutting method is less the individual grains cutting the steel, but rather the surface texture that does it. That is to say, they function more analogously to a file. You can lap these stones on loose abrasive grit (lapidary diamond recommended) to condition the surface to different degrees of roughness that will cut more or less aggressively, much like coarse and fine file cuts, despite the files themselves being made of the same steel in either case. The grit size of the stone essentially doesn't matter in this scenario, and should not be focused on.

If you don't like how one is cutting compared to the other...just resurface it.

 

[Papilio]

For me that has always been a one way. Finer, yes. But coarser? Need to try loose abrasive grit. Diamond stones didn't work, they just made the surface finish finer.
When the stone was new, I wanted the DC4 to be much finer. Now I want it rougher. You always want to have, what you don't have....

I think I have read a post in the Spyderco forum, where more or less the same topic was discussed. It was the same thing Fallkniven states: The stone gets finer when you use it. Will it be too fine / smooth at some point? Can you resurface an ultra fine stone coarser? Sal Glesser said no, as far as I remember.
But: The UF is a fine stone with a finer surface finish. If you can make it finer, you can make it coarser?

 

[FortyTwoBlades]

For me that has always been a one way. Finer, yes. But coarser? Need to try loose abrasive grit. Diamond stones didn't work, they just made the surface finish finer.
When the stone was new, I wanted the DC4 to be much finer. Now I want it rougher. You always want to have, what you don't have....

I think I have read a post in the Spyderco forum, where more or less the same topic was discussed. It was the same thing Fallkniven states: The stone gets finer when you use it. Will it be too fine / smooth at some point? Can you resurface an ultra fine stone coarser? Sal Glesser said no, as far as I remember.
But: The UF is a fine stone with a finer surface finish. If you can make it finer, you can make it coarser?

Yes, you can refinish them coarser using coarse lapidary diamond grit. The method I was referring to was not using diamond plates, and I do not recommend that method for lapping/conditioning. The loose grit method is faster and produces better results.

You do need to eventually dress sintered ceramics, since they don't shed grit on their own. When the surface grains blunt and start burnishing instead of cutting you need to recondition it to remove the surface layer of grit and expose fresh-cutting grains with a retextured surface at the desired level of aggression.

 

[Papilio]

Yes, you can refinish them coarser using coarse lapidary diamond grit. The method I was referring to was not using diamond plates, and I do not recommend that method for lapping/conditioning. The loose grit method is faster and produces better results.

When I started sharpening I thought I just would need a stone, or two.

You do need to eventually dress sintered ceramics, since they don't shed grit on their own. When the surface grains blunt and start burnishing instead of cutting you need to recondition it to remove the surface layer of grit and expose fresh-cutting grains with a retextured surface at the desired level of aggression.

Fallkniven and Spyderco stones are always described as low maintenance ("stay flat virtually forever"). Hardly no one is ever talking about this dressing thing.
Next time I buy Japanese waterstones...

 

[FortyTwoBlades]

When I started sharpening I thought I just would need a stone, or two.


Fallkniven and Spyderco stones are always described as low maintenance ("stay flat virtually forever"). Hardly no one is ever talking about this dressing thing.
Next time I buy Japanese waterstones...

Basically all stones require some degree of maintenance. It's true that the sintered ceramics stay FLAT forever. But that's because they don't shed grit, so depending on how heavily they're used and on what steels the surface grains will blunt over time, and eventually do little more than rub/burnish instead of actually sharpening. Japanese water stones are the polar opposite, and tend to be very soft, which makes final apexing annoying at times, but they cut very quickly because they are continuously exposing fresh grit. They do often require frequent flattening as a result.

The loose grit method is very simple and easy and basically anyone doing sharpening work should get themselves a black granite flooring tile and at least one bag of loose grit of appropriate type/size. It just works fast and easy for flattening most stone types.

Sintered ceramics don't need dressing often, since they're mostly used for light touchups and final honing. But they do eventually need it.

 

[Papilio]

Could you give me an example for a loose grit you are talking about? I can only find SiC powder (which seems to be inferior on sintered ceramics) or very fine diamond for honing / stropping.

 

[FortyTwoBlades]

Lapidary diamond powder is what you're looking for. I find the stuff from Tech Diamond Tools does a very good job. They have a wide range of grits at very reasonable prices. You only need a small pinch of the stuff to do the job.

 

[Papilio]

Thank you very much.

 

[311climber]

They all use synthetic sapphires (aluminum oxide) and they all have a mix of grain sizes averaging 15µ but those are not the important part here. Abrasives in general rely on more than just the grit size to affect the finish produced and relative cut speed, and sintered ceramics even more so.

Sintered ceramics are binderless and are basically like synthetic sedimentary rock, with the enormous heat and pressure used in their creation causing the grains to fuse with one another. This not only makes for a very hard bond, but the grains are in a range of sizes to make them easier to fuse--if they were all one size they wouldn't want to stick together so readily. However the final product's cutting method is less the individual grains cutting the steel, but rather the surface texture that does it. That is to say, they function more analogously to a file. You can lap these stones on loose abrasive grit (lapidary diamond recommended) to condition the surface to different degrees of roughness that will cut more or less aggressively, much like coarse and fine file cuts, despite the files themselves being made of the same steel in either case. The grit size of the stone essentially doesn't matter in this scenario, and should not be focused on.

If you don't like how one is cutting compared to the other...just resurface it.

ive heard this for a long time about the sintered ceramics, ive lapped a few surfaces with 60 grit sic on the medium to get it a little more aggresive and that works but it doesnt last long. i know you have your own line of stones and am curious, have you ever purchased the kme ceramic versions of their benchstones? the texture is far more porous by comparison to spyderco, and you dont need to lap them for a temp. solution. i do believe these kme ceramics must have a bunch of way larger sapphires they press together, you can per say see the grit and it looks way more defined then the spy med. of course they cut way faster im guessing to the media size, but whats your thoughts? can they use small grain in a fashion or a process where its still a bit more porous or is it safe to assume you need bigger media to create said voids?

 

[311climber]

They all use synthetic sapphires (aluminum oxide) and they all have a mix of grain sizes averaging 15µ but those are not the important part here. Abrasives in general rely on more than just the grit size to affect the finish produced and relative cut speed, and sintered ceramics even more so.

Sintered ceramics are binderless and are basically like synthetic sedimentary rock, with the enormous heat and pressure used in their creation causing the grains to fuse with one another. This not only makes for a very hard bond, but the grains are in a range of sizes to make them easier to fuse--if they were all one size they wouldn't want to stick together so readily. However the final product's cutting method is less the individual grains cutting the steel, but rather the surface texture that does it. That is to say, they function more analogously to a file. You can lap these stones on loose abrasive grit (lapidary diamond recommended) to condition the surface to different degrees of roughness that will cut more or less aggressively, much like coarse and fine file cuts, despite the files themselves being made of the same steel in either case. The grit size of the stone essentially doesn't matter in this scenario, and should not be focused on.

If you don't like how one is cutting compared to the other...just resurface it.

while thinking aloud, the reason im less convinced that resurfacing is the way to go is because of the medias stock surface. when you score up a piece of plate glass with low grit sic you change the surface texture, we all know that, but when you get through that roughing you produced theres nothing but super fine smooth glass below, so its a temporary solution not in a sense how the stone is supposed to be used. (not saying you cant of course multi purpose a stone) i think you said below, the original surface, or the surface you create after using the stone for awhile is the true composition of the stone and should be used in the sequence it fits. hense why resurfacing a med. spyderco isnt its true calling to cut material fast, sure i can spread jam on toast with a samurai odachi, or use a butter knife. just seems weird i know we all like multi functional items but after trial of making a stone coarser, that stone slowly goes back to its original sintered format

 

[FortyTwoBlades]

Sintered stones don't shed grit. It doesn't work the same way. And they are made using a range of different grit, as it aids the sintering process. If you tried to create a sintered stone using all one grade of grit you'd have a VERY difficult time getting it to fuse. What you are describing is just not how they work. They are not the same as vitrified, resin-bonded, or coated abrasives, all of which have their own unique behaviors. Sintered stones rely more on their surface texture than anything else to create their abrasive effect.

 

[311climber]

how do they work then? i know for a fact i have lapped a ton of spyderco UF stones with sic powder on glass and my sic turns pure white like alum ox. i do understand that under normal blade use the sintered ceramics dont shed to the eye. i just think the medium one that i lapped one side to 60 grit has shed some of the valleys i made with the sic. just like any polished ceramic, its cutting less and polishing more now. you can feel the aggression is no longer there as it was at first. so are you saying the aggresive texture i started with wasnt planed off? earlier i had asked if you used the kme 6 inch ceramic bench stones just to reference they were the most aggresive sized multi-grained brown alum. oxide stones ive seen. i dont believe i was ever saying they were made with identical sized particles. i was saying i believe kme used larger grit when producing their bench stones, and asking you, can you create a very porous stone from using varying smaller grit, or is it safe to assume the larger the grit, the more porous it will be?

 

[FortyTwoBlades]

how do they work then? i know for a fact i have lapped a ton of spyderco UF stones with sic powder on glass and my sic turns pure white like alum ox. i do understand that under normal blade use the sintered ceramics dont shed to the eye. i just think the medium one that i lapped one side to 60 grit has shed some of the valleys i made with the sic. just like any polished ceramic, its cutting less and polishing more now. you can feel the aggression is no longer there as it was at first. so are you saying the aggresive texture i started with wasnt planed off? earlier i had asked if you used the kme 6 inch ceramic bench stones just to reference they were the most aggresive sized multi-grained brown alum. oxide stones ive seen. i dont believe i was ever saying they were made with identical sized particles. i was saying i believe kme used larger grit when producing their bench stones, and asking you, can you create a very porous stone from using varying smaller grit, or is it safe to assume the larger the grit, the more porous it will be?

What you're experiencing is blunting of the grains at the peaks of the surface texture, leading to burnishing rather than cutting. This is much like what occurs when a file blunts. Regarding grit size you said:

i do believe these kme ceramics must have a bunch of way larger sapphires they press together, you can per say see the grit and it looks way more defined then the spy med. of course they cut way faster im guessing to the media size, but whats your thoughts? can they use small grain in a fashion or a process where its still a bit more porous or is it safe to assume you need bigger media to create said voids?

My point was that they inherently use a range of grit size, and any larger grains will be surrounded by finer ones, meaning your grit protrusion will always be pretty low regardless of the maximum size in the mix.

 

[311climber]

that makes more sense now. thanks for explaning!