Spyderco Ceramic Stone, Flattening?

[Jim Stewart]

I have an 8x3 Spyderco Ceramic stone, and an 8x2 brown medium stone. I read a thread not long ago and George Wilson commented that the newer Spyderco stones have swirl marks in them. Bingo! That is what I have. These stones seem to be very good, but I was wondering about flattening them. Is it possible? I don't want to ruin a diamond stone by trying to do it. I mainly use these stones on hollows and rounds and gouges. That being the case I don't really need them to be dead flat..right?

[Steve Friedman]

Yup. Just did it on all three (medium. fine, and ultra) with my Atoma diamond plates. In all fairness, I have both the #140 and #400 Atoma plates which made it possible. I also did it under running water (per George's suggestion). The medium was easy, the other two not so much. I went at them alternating between the #140 and #400 diamond plates. It was work, but I did finally get all of the stones flat on both sides. I finished the medium with the #140, but finished the other two with the #400.

Tested the diamond plates on my waterstones after I was done and they still cut fine. No difference noted.

If you don't already have diamond stones, it's an expensive way to flatten the Spyderco stones, which are guaranteed to arrive flat. If I didn't already have the Atoma plates, I would have returned the Spyderco stones for flat ones.

Steve

[Chris Griggs]

I'm guessing coarse loose diamonds or coarse SiC would also work, but don't know for sure (especially about the SiC). Anyone have thoughts on this?

[Shaun Mahood]

Here is a previous thread with a few details on flattening the spyderco stones

http://www.sawmillcreek.org/showthread.php?169703-USPS-has-delivered-How-do-I-flatten-ceramic-stones

[george wilson]

At least my stones did not have those swirl marks on them. The brown stone was o.k.. The white Spyderco had some PERMANENT ceramic "fuzz" on it which I got rid of. Had I not,the fuzz would never have gotten worn off.

It would be nice if Spyderco would make progress in the right direction,rather than making their stones even worse. I had better not ever drop mine and have to replace them!!

[Steve Friedman]

I don't know if my stones would have had the marks on them. Never got that far. I read the old thread before ordering them, so I expected the stones not to be flat (sad, I know). So, I unpacked them, checked with a straight edge just to confirm that they weren't flat (they weren't) and went at them with the diamond plates for a few hours.

Were it not for wanting something harder than waterstones to use on carving gouges, I don't think I would have bought the Spyderco stones.

Seve

[David Weaver]

I used a 400 grit atoma dry on a spyderco UF. Dry, as in bone dry (important if it's not going to be wet) and the stone was dry.

The reason bone dry is important is because you need to be able to brush the dusty stone swarf (don't breathe, it's probably not good for you) off of the atoma periodically.

It worked well, but it wasn't super quick. Under water would work OK, but it was harder for me to check progress that way. Either totally bone dry or under water both work.

[Jim Stewart]

Thanks guys, Jim

[Robert McNaull]

I just ordered a 1200 and 8000 sigma stones from Stu's store and was having the same questions about how to flatten them. I didn't spring for a diamond plate as I couldn't currently justify the cost, I think. I have a coarse silicon carbide flattening stone that I use on my cheap water stone. Could this work for the ceramic stone flattening as well? I dropped the link to the stone I have, I can't remember board rules on these so I aplogize if I'm not supposed to link it, just say so and I'll remove it.

http://www.hartvilletool.com/product/1016/water-stones

[David Weaver]

The 1200 is a hard stone. It'll eat up the norton flattening stone and just cause the surface of the flattening stone to be graded.

If diamond is out of the budget, you want to order a pound of silicon carbide grit in about 220 for your 1200 and rub the stone on loose grit on a flat surface and rinse it off.

Never used the 1000 stone, so couldn't really tell you what it requires. Stu can.

[Jonathan McCullough]

Hasn't anyone ever tried using a belt grinder on these Spydercos? Seems like it would take a lot of the drudgery out of getting these flat. I've got a brown banana-shaped Spyderco and a belt grinder. If no one can speak to this, maybe I should become the first "expert" on the subject. I've already flattened an UF and it took a very long time. Very happy with it now, but a v e r y l o n g t i m e. Worth sacrificing a HF belt or two to get it over with.

[David Weaver]

Give it a rip. Getting the belt moving and taking a light cut is the only way that it won't be instant death to the abrasive.

[Steve Friedman]

Jonathan,

If you've already done the UF, the brown will be a cinch. Must faster going. I can't imagine holding the stone steady enough to get it flat on a belt grinder, but would think it might work to take down the real high spots and get close. I am not sure that aluminum oxide will work, since the ceramic is (I believe) harder that that. If you try it, please report results. I agree with David's suggestion about loose using silicon carbide grit to flatten it. For the brown stone, I think you can start with 90 grit since it breaks down pretty quickly.

Steve

[Robert McNaull]

Thanks David, I almost ordered an atoms but didn't. I might pick up a dmt diamond plate. Is there a recommendation on grit? I know stu sells a 400 atoma with with the discount kits.

[Harry Rosal]

Lurker here,


...well, say i'll get a 2"X8" medium and a 2"X8" UF, can't i just rub the two together? Maybe i won't get perfection but i'm bound to end up flatter than i started right?

If it's slow going, or glazing, or whatever the issue could be, I'm thinking sprinkling loose grits (as suggested) between the spyderco sandwich should then make it work?

I only have the pocketable, spyderco "double stuff" so i have no means of trying out what i just said unfortunately, and i might be getting the big stones further down the road.

[David Barnett]

In 2008, Sal Glesser, founder & president of Spyderco, explained the three bench stone grades (http://www.spyderco.com/forums/showthread.php?31188-Ceramic-benchstones-compared-to-DMT-extra-fine&p=395490#post395490).

Our gray stone is "medium". (Same material as fine but different carriers and heat treat).

Our fine stone is fine.

Our extra fine is a surface ground fine.

On using diamond stones to flatten a Spyderco fine. (http://www.spyderco.com/forums/showthread.php?31188-Ceramic-benchstones-compared-to-DMT-extra-fine&p=401328#post401328)

I've sacrificed a few DMT stones turning fines into ultra fines before we made them.

The fine is "as fired".

So, if Sal is to be believed, Spyderco bench stones have the same abrasive material with two different ceramic carriers and surface treatments.


... I was wondering about flattening them. Is it possible?

Yes, they can be flattened.


I don't want to ruin a diamond stone by trying to do it.

Sal "sacrificed" DMT stones to flattening.


... I don't really need them to be dead flat..right?

Your call. I don't need mine dead flat for sharpening gravers, narrow chisels, netsuke knives and most carving gouges. For most chisels and plane blades, though, I'd want dead flat.

[David Weaver]

Thanks David, I almost ordered an atoms but didn't. I might pick up a dmt diamond plate. Is there a recommendation on grit? I know stu sells a 400 atoma with with the discount kits.

400 atoma or 325 DMT. Either is a good choice for medium and fine stones. If you get the DMT, get the duo sharp and shop around for the cheapest 8x3. Should be about 60 bucks. The atoma is better, though, if the price is even close.

[David Weaver]

Lurker here,


...well, say i'll get a 2"X8" medium and a 2"X8" UF, can't i just rub the two together? Maybe i won't get perfection but i'm bound to end up flatter than i started right?

If it's slow going, or glazing, or whatever the issue could be, I'm thinking sprinkling loose grits (as suggested) between the spyderco sandwich should then make it work?

I only have the pocketable, spyderco "double stuff" so i have no means of trying out what i just said unfortunately, and i might be getting the big stones further down the road.

Start with the loose grit, and have a third surface, even if it's the back of one of the stones. If you just rub two spydercos together (I don't know what that would sound like, could sound like fingernails on a chalk board), then they will glaze over.

[Steve Friedman]

David,

Thanks for the link to the Spyderco site, but that made me even more confused than I was before. How is it possible that all three Spyderco stones have the exact same sized grit and the only difference is the binder and finish. If true, then wouldn't flattening them with diamond stones mean you end up with three ceramic stones of the exact same grit? I don't get it.

Steve

[David Weaver]

I'm the wrong david, but you can make finer abrasives cut coarsely if you put some space between the blobs of abrasive grit. That is essentially what makes dense oilstones finer than less dense oilstones - how tightly packed the particles are.

[David Barnett]

How is it possible that all three Spyderco stones have the exact same sized grit and the only difference is the binder and finish.

Grit size isn't the whole story—not by a long shot. What holds and presents the grit is very important. For example, a resin-bond diamond lap will cut faster with a smoother scratch pattern* than an electrobond lap of the same-sized diamond crystals while requiring no break-in whatsoever. Loose diamond will cut differently than bonded diamond, monocrystalline than polycrystalline, and so on.

David W's absolutely correct. The density of the silica, how tightly it's bound, it's presentation and fractioning characteristics determine the grade of novaculite.

And so it is with naturals and man-mades of all sorts. The matrix and binders, what Glesser calls "carriers", determine how deeply, how evenly and quickly a bench stone will cut and how quickly it will wear away—how the particles of abrasive will fracture and/or be released, rapidly as in softer waterstones or conversely in ceramics and the denser novaculites.

I'm not just theorizing, either. I have years of hands-on experience making and using sintered and ceramic abrasive points, wheels and laps for gem carving, first employing Henry Hunt's methods before moving on and extending my technique, so can better appreciate Glesser's considerable accomplishments, having tackled first-hand the variables involved and the effort required to control them. To say it's challenging to balance kiln temperatures, heat work and firing schedules, clay bodies, slips and abrasives into consistently usable results with low discard rate is oversimplification and understatement at its richest.

As Hunt says in Lapidary Carving for Creative Jewelry —

"The important thing in making ceramic grinding wheels is the temperature at which they are fired. Too high and the wheel is so hard it won't cut. Too low and the wheel wears away between eye blinks. A difference of 100° can make or break you as a wheelmaker."

And believe me, there's a lot to learn in within that 100° and a lot more to it than temperature alone, which is just one reason most gem carvers have migrated to electrobond or sintered diamond points & wheels or to high-diamond-density pastes on wood.


If true, then wouldn't flattening them with diamond stones mean you end up with three ceramic stones of the exact same grit? I don't get it.

When Glesser flattened his fine it wasn't so much to produce a stone with improved edge-to-edge flatness but to change its cutting characteristics from fine to ultra-fine.

What effect diamond flattening has on a medium Spyderco stone I cannot say, but I'd intuit it would change its cutting characteristics, although it might simply slow it down—probably not what you're after.

If my goal was edge-to-edge flatness across a ceramic bench stone, and if I chose diamond to achieve it, I'd choose loose diamond over electrobond diamond plates or bench stones.

My reasons? My lapping substrates are of known flatness, loose diamond is far cheaper than electrobond diamond laps or bench stones, there are more grit sizes compared to bench stones, it's faster and more efficient—almost the entire loose crystal gets presented and consumed whereas electrobond does not, loose diamond can be refreshed as needed, and lastly, I have a lot of it.

*A Raytech Nu-bond 600-grit resin-bond lap cuts as smooth or smoother than a 1200-grit electrobond lap in less time, and will do so consistently over the life of the lap.

[Steve Friedman]

Thanks to both Davids. Much of it is way over my head, but, having already flattened my Spyderco stones with Atoma plates, do I need to do something to fix the surface? Since I never used them before flattening, I have no idea how they are supposed to feel and cut.

Also, is using diamond paste OK or are loose diamond stones really that much better for this purpose? I have diamond paste up to 45 micron, but can get some even grittier. What size grit do you suggest for repairing the surface of the three different grit stones? I assume different grits for the different stones, right?

Steve

[David Weaver]

Don't know about the medium, but for the UF, you can just use it as you have it now. It will probably cut very fast at first, but it will settle in to much finer pretty quickly.

I wouldn't use diamond paste unless it's water based. Loose diamonds that you can get on ebay (dry) are the way to go to condition the surface of the medium if it's cutting too fine.

Check the medium first to see how it's cutting. It might be just what you want already. If it seems slow, you can find some coarse loose diamonds (ebay is a good place) to open up the surface.

[Steve Friedman]

Don't know about the medium, but for the UF, you can just use it as you have it now. It will probably cut very fast at first, but it will settle in to much finer pretty quickly.

I wouldn't use diamond paste unless it's water based. Loose diamonds that you can get on ebay (dry) are the way to go to condition the surface of the medium if it's cutting too fine.

Check the medium first to see how it's cutting. It might be just what you want already. If it seems slow, you can find some coarse loose diamonds (ebay is a good place) to open up the surface.
Thanks David,

I have never used loose diamonds before. What size would you use?

Steve

[David Weaver]

Go big....100 or 120 grit to condition the stone. 100 carats of 120 grit diamonds are about $25 and they are very handy to have around to remove pitting from anything hard.

Here's a guy I've used before (ebay listing)

221124842714

no affiliation, just recommending him purely because he's *cheap*. If you want more or less or different grits, you can sift through his store.

[David Barnett]

Thanks to both Davids. Much of it is way over my head, but, having already flattened my Spyderco stones with Atoma plates, do I need to do something to fix the surface? Since I never used them before flattening, I have no idea how they are supposed to feel and cut.

Although I don't use Spyderco bench stones for woodworking tools, I'd guess you now more or less have one fine or medium-fine and two ultra-fine stones, but Spyderco can better tell you than I. I also doubt you can replicate the original cutting characteristics of either the medium or fine, so I'd be inclined to simply use them in their altered state and see if they perform positively for you. One strategy might be to allow your original ultra-fine to load up and use it as a final finish or polish stone—it performs admirably for this—something suggested by David W, as I recall.

Spyderco has been very accommodating in putting flat stones into the hands of those who feel their stones fail to meet expectations, even after normal use—they're quite aware that what might be entirely adequate for some knivees might be less so for woodworking chisels and plane blades—but diamond lapping may fall outside even Spyderco's liberal exchange policy. At any rate, I'd call or write them, explain your concerns and actions and see what they say.

My medium and fine stones are older 2" x 8" stones, and I was fortunate to have a pile from which to test and choose, so have never flattened mine. Because the ultra-fine stones are surface ground, they should be flat from the start, but you may wish to remove the swirl marks. I'd be interested in what Spyderco has to say.

For others thinking about purchasing Spyderco stones, I'd advise sending them back if they're not as flat as you'd expect. I've known two persons to did so and they both received stones that were very flat indeed.


What size grit do you suggest for repairing the surface of the three different grit stones? I assume different grits for the different stones, right?

I don't have a suggestion as to what grit size might rehabilitate your bench stones. I simply don't know. Hopefully, Spyderco can help answer that, and again, I'd certainly be interested in what they'd say.


Also, is using diamond paste OK or are loose diamond stones really that much better for this purpose? What size grit do you suggest for repairing the surface of the three different grit stones? I assume different grits for the different stones, right?

For lapping larger surfaces, lapping on substrates where oil is not wanted, and/or where swarf handling and cleaning present unique issues, loose diamond might be more appropriate.

Diamond paste is, for the most part, loose diamond. I make my own compound and simply add loose diamond to my preferred medium; mostly petroleum jelly with kaolin (china clay) now that the older olive oil paste is unobtainable.

Diamond compound does let one easily control the amount of diamond and keep it where you want it.

"I eat my peas with honey.
I have done it all my life.
It do taste kind o' funny,
but it keeps 'em on my knife."
—Burma Shave

[David Weaver]

This whole conversation encouraged me to drop a few dimes on a spyderco medium. It's one of the few stones that I've wanted to try that I resisted buying until now. I like the UF, though I'd bet it will frustrate a lot of folks used to friable stones.

[David Barnett]

I just edited my above response to include your suggestion to allow the UF to load, using it for a final finishing stone, much as I use my harder jaspers.

The medium is a favorite with engravers, chip carvers and so on. Of my not-so-friable non-diamond bench stones, the medium gets the most use. It's a really good stone.

[David Weaver]

I have some curiosity about it, thus the inability to resist. I dismissed it out of hand initially figuring that it would be a project to keep it fresh cutting, but if it is porous (for some reason, I figured it was compacted larger grits instead of a more open matrix), then I was probably off base.

The UF will glaze over if not kept after, but it's a great base to use anything on. I've even used it with loose japanese finish stone grit (which is very coarse compared to all of the micron and sub micron offerings). Works well with diamonds, too, as long as you have them rolling on purpose, as far as i can tell, they don't embed.

[David Barnett]

I like the UF, though I'd bet it will frustrate a lot of folks used to friable stones.

No doubt! It does remove metal, but precious little. I have a currently favored jasper variety that's more aggressive than either the UF or some of my harder jaspers, but leaves an amazingly polished edge on both high-carbon and HSS.

264315

Streaks from top to bottom:
• GlenSteel, non-cobalt HSS graver from GRS
• M2 vanilla HSS
• O1, oil-quenched HC tool steel
• W1, water/brine-quenched HC tool

No oil, no water, dry.

[David Barnett]

I have some curiosity about it, thus the inability to resist. I dismissed it out of hand initially figuring that it would be a project to keep it fresh cutting, but if it is porous (for some reason, I figured it was compacted larger grits instead of a more open matrix), then I was probably off base.

It's more porous (but not especially so) than the fine but seems every bit as hard and is easily cleared with a pinch of dry abrasive cleanser and a few drops of water rubbed in small circles then rinsed with a squirt bottle. One could use a nonwoven pad, of course.


The UF will glaze over if not kept aftter, but it's a great base to use anything on. ... Works well with diamonds, too, as long as you have them rolling on purpose, as far as i can tell, they don't embed.

As a faceter, I learned to polish rubies and sapphires on ceramic laps charged with ½µ (50,000/60,000 grit) spray diamond. I use ½µ on both ceramic and BATT laps, nowadays, preferring the BATT for corundum and ceramic for graver heeling and polishing—the only time I use submicron diamond on steel, really—making a huge difference on high-carbon for bright-cutting silver and HSS for anything harder.

The trick on ceramic for both corundum or steel is to remove as much diamond as possible before touching to either gem or steel. Spray the least, most evenly possible diamond coating from 10 or 12", then wipe clean. Squeegee thoroughly with a fresh single-edge razor blade at low rpm, then wipe again with pure alcohol and a paper towel, repeating this last step at least once until it squeaks dry, eliminating free-rolling diamond particles and any too-large outliers.

1µ, 3µ or even 6µ diamond's also great for cleaning and refreshing hard Arkansas stones, of course. Paste works just fine.

[Harold Burrell]

This whole conversation encouraged me to drop a few dimes on a spyderco medium.

What? Seriously? You bought another stone?

No way...

;)

[Steve Friedman]

After re-reading the Spyderco forum thread again, I am troubled by a comment made by Sal Glesser, who I gather is the owner of Spyderco. In response to a question about grit size, he says,

"We've spent a great deal of time trying to determine grits for our stones. The manufacturer has also worked with us, to no avail. A guess seems to be best. Most abrasives are measured by the grit size used in the matrix. Our ceramic doesn't work that way. Grit size is constant. We've tried to compare scratch patterns . . . this is probably the closest, but nothing that we can say 'This is blah blah'. Then the Japanese water stones jump into the equation and suddenly there is whole new set of numbers. So where we end up is . . . Our gray stone is "medium". (Same material as fine but different carriers and heat treat). Our fine stone is fine. Our extra fine is a surface ground fine."

Huh? I am sure that Mr. Glesser is very knowledgable, but for me that answer translates to, "I don't know." It also seems pretty clear that Spyderco doesn't make their ceramic stones and is relying on what the manufacturer is telling them about grit size and what makes the stones work. Not trying to be a cynic or question the quality of the stones (although my 8 x 3 UF was NOT flat), but has there ever been anything definitive (scientific) to indicate what these stones are really made of and how they work? Does anyone else make similar ceramic stones?

Just wondering,

Steve

[David Barnett]

I am sure that Mr. Glesser is very knowledgable, but for me that answer translates to, "I don't know." It also seems pretty clear that Spyderco doesn't make their ceramic stones and is relying on what the manufacturer is telling them about grit size and what makes the stones work.

I understand what Glesser is saying and find no problem with it. Like many companies, the conception, development and specification for a product is done in-house then outsourced to an appropriate manufacturer, and Glesser's manufacturer working with him to find meaningful grit equivalents is not at all surprising nor in any way reflects questionably on Spyderco, as I see it.

What you may not really understand is that what grit a stone is determined to be, what abrasive is used, its grit range and crystal habit, is secondary to its performance as described in the examples I offered. The question Mr. Glesser's trying to answer is where on a scale of equivalent grits—one of several developed through a consensus of interested, inquiring users attempting to arrange a large sample of stones by their relative component grit sizes and cutting characteristics—does a given Spyderco stone fall.

The problem really becomes can a stone's grit size accurately predict or describe the various performance characteristics of that stone or any other stone. It is this Mr. Glesser is doing his candid best to address—where do the Spyderco bench stones properly fall on such grit equivalence scales. Because one industry freely offers grit component sizes for their stones—not all do—it doesn't necessarily follow that another maker's stones, systems which incorporate those very same abrasive components, will cut, wear and produce similar scratch patterns as the first company's stones.

Glesser's statement: "Most abrasives are measured by the grit size used in the matrix. Our ceramic doesn't work that way." is dead accurate. While grit size may be more descriptively meaningful for highly friable sharpening systems, for harder matrix systems, not so much.

The convention of using grit sizes to differentiate one stone from another is, at best, a convenience to unsophisticated buyers and a useful way to scale the relative cutting characteristics of a manufacturer's line, and at worst, misleading. It's like trying to describe composers by their comparative number of notes per measure, so I find Sal Glesser's answer refreshing, realistic and honest.


Not trying to be a cynic or question the quality of the stones (although my 8 x 3 UF was NOT flat), but has there ever been anything definitive (scientific) to indicate what these stones are really made of and how they work? Does anyone else make similar ceramic stones?

Not definitive if you mean in all-encompassing breadth of stones tested, although studies have been rigorously scientific within more limited sample domains. The literature on abrasive technologies, as you might expect, is vast. Unfortunately, bench stone analysis gets short shrift as such pursuits go, but it's enough to keep a few of us interested and entertained—seemingly endlessly.

And yes, Spyderco is hardly the only maker of ceramic abrasive products, although they certainly have the ceramic bench stone markets for woodworkers and food preparation specialists.

I do understand your disappointment with flatness issues and do hope that Spyderco can offer some help even though you've attempted your own fix. The ultra-fine really should've been flat, in my opinion. I hope it works out positively for you.

[Steve Friedman]

Thanks for your explanation David. That actually makes sense in relation to friable water stones, but I still don't get how two ceramic stones can cut differently when they contain the exact same size grit. Would two diamond plates with equal sized diamonds cut differently just because one of the plates had the diamonds spaced out differently or embedded at different depths? How can very hard 25 micron abrasive particles create the same level of finish as a stone with 1 or 2 micron particles? It doesn't seem possible.

I see that Wayne Barton and Dennis Moor manufacture and sell ceramic stones that look and sound remarkably like the Spyderco one. The Moor stones (which I believe are the ones sold by Lee Valley) are described as 800 and 8000 grit. No description on the Barton stones.

Thanks again for trying to help me understand.

Steve

[David Barnett]

Would two diamond plates with equal sized diamonds cut differently just because one of the plates had the diamonds spaced out differently or embedded at different depths?

They sure can. A lot of other factors come into play, too, such as the crystal habit—whether it's monocrystalline or polycrystalline—the electrobonding technology, the electrobonding formulation and deposition thickness, diamond distribution characteristics, the particle size range for that diamond, its standard deviation and skew to larger or smaller outliers, the amount of diamond used, its alignment, exposure and other presentation factors, and so on.

For example, the 3M films have remarkably tight grading for size and astonishlingly regular alignments which produce highly homogenous scratch patterns and cut quite differently from most other diamond abrasive technologies.

For another example, let's focus on just one factor, the difference between monocrystalline and polycrystalline diamond particles of similar size affixed to bench stones through electrobonding, rather than the two interesting but more technically challenging factors you named.

Polycrystalline stones have distribution and wear characteristics that produce smoother scratch patterns and can last longer and improve with age and use—my favorite Eze-Lap is coming up on 20 years—whereas monocrystalline stones of similar grit size cut deeper and more aggressively at first but also gives up the ghost rather quickly—one reason I prefer polycrystalline over monocrystalline bench stones.

I think monocrystalline diamond is best used where aggressive, fast-cutting with consistently-graded particle size is desired over durability and evolved fineness of cut—not my requirement for bench stones. So, you see, it's truly more than particle size alone.

Because many first-time buyers encountered monocrystalline bench stones such as DMT, their expectations for polycrystalline stones can be unrealistic and unsophisticated, which is why monocrystalline may be mixed with polycrystalline diamond to compensate for this*. While some manufacturers claim this improves distribution (closest packing) and cutting characteristics, I am dubious of such statements.

At any rate, before mono was added to poly, you can hardly imagine how many polycrystalline stones were discarded or given to me when they'd just begun to be broken-in, having lost what I considered deleterious and annoying initial roughness, in spite of my protestations, explanations and efforts to get their owners to continue using them. All this and particle size had little to do with any of it.

So yes, different diamond stones with similar grit sizes certainly can and do cut differently and the same goes for ceramics. We'll not even go into diamond laps for gem faceting.


... I still don't get how two ceramic stones can cut differently when they contain the exact same size grit.

How can very hard 25 micron abrasive particles create the same level of finish as a stone with 1 or 2 micron particles? It doesn't seem possible.

Very much the same way novaculite, a chert, cuts steel. The cutting grit size in soft, medium and hard Arkansas stones centers roughly around 4µ for all three, with a rule of thumb range of 3µ to 5µ skewed to the larger particle size, yet the softest cuts coarsely and quickly while the hardest cuts finely and more slowly. The difference is in the density of cutting particles and the matrix that presents them.

Think of it this way—if you had some sharp sand, not beach or playground sand, embedded in chalk, the chalk surrounding your cutting particles would wear away, exposing the grains of sand to greater depth, which would cut a coarser pattern. Chalk being soft will more readily release its loosely-packed grains than a harder surrounding substance, such as hard casting plaster, so will wear more quickly before the cutting grains have lost all their coarse-cutting sharpness.

The very hard matrix in a hard Arkansas stone tightly holds and presents its cutting grains, hardly eroding or wearing away from around them, exposing less of each grain above the matrix surface. What's more, those grains are far more densely packed than in stones having softer matrix material, so the hard Arkansas cuts finely due to less cutting grain exposure and the denser packing of adjacent cutting grains to one another.

As the exposed cutting grains become less sharp with use, the stone will cut more slowly but even more finely, eventually leveling off, reaching a plateau, settling into its long-term cutting habit. No matter which Arkansas stone you choose, its cutting characteristics will be largely determined by its density of cutting particles and its matrix rather than the 4µ average size of its cutting grains.


I see that Wayne Barton and Dennis Moor manufacture and sell ceramic stones that look and sound remarkably like the Spyderco one.
As to the origin of Wayne Barton's ceramic stones, I've seen that, too—that Barton now manufactures his own (http://www.mhcrafters.com/servlet/the-1851/Set-of-Wayne-Barton/Detail). Whether or not this is so I wouldn't know. It's possible, of course, but I'd be hard-pressed to see the cost benefit for what I'd imagine the chip carving market to be.

Anyway, I hope this makes things a bit clearer despite its length and do feel free to keep asking questions as I rather enjoy answering them.

*While I'm not a fan of this practice, doing so in moderation shouldn't adversely affect the predominantly polycrystalline bench stone's surface over the longer term, as the stone will soon lose its added break-in aggressiveness as the monocrystalline diamond breaks down far more quickly than the polycrystalline. Pure polycrystalline laps, pastes and loose diamond are to be strongly preferred over mixtures, in my opinion, with monocrystalline films being an exception for certain polishing applications.

[David Weaver]

What? Seriously? You bought another stone?

No way...

;)

Happens sometimes. Forums certainly drive purchasing. At least they drive woodworking and toolmaking, too.:)

[David Weaver]

No doubt! It does remove metal, but precious little. I have a currently favored jasper variety that's more aggressive than either the UF or some of my harder jaspers, but leaves an amazingly polished edge on both high-carbon and HSS.

264315

Streaks from top to bottom:
• GlenSteel, non-cobalt HSS graver from GRS
• M2 vanilla HSS
• O1, oil-quenched HC tool steel
• W1, water/brine-quenched HC tool

No oil, no water, dry.

I wonder how much of the jasper's action is pushing the steel around on the gravers vs. abrading it. Obviously, some os being abraded. I've never paid too much attention to what separates the grains of steel from whatever's being sharpened, but assume that either through adhesion or some other mechanism, molecules can be removed without slicing them off in bits.

There are enough flat pieces of jasper that appear to be nonporous on ebay for $10 that I think I'll give them a whirl. The pieces that I've seen sold as hones are *much* more expensive, and if there are no pores on the surface, the surface has taken a polish and the stone is hard enough to not release grit, I'm not sure I care too much how large the underlying grits are.

[David Barnett]

I wonder how much of the jasper's action is pushing the steel around on the gravers vs. abrading it. Obviously, some os being abraded.

Surprisingly, streak tests show that some jaspers remove more metal than my hard translucent Arkansas. Some, as you might expect, less so and with more burnishing action. The same steel with the same cross section, same hardness, length and breadth of streak when weighed on an analytical balance after a multiple-streak test proves this.


The pieces that I've seen sold as hones are *much* more expensive, and if there are no pores on the surface, the surface has taken a polish and the stone is hard enough to not release grit, I'm not sure I care too much how large the underlying grits are.

Yes, and far more for novelty and adornment than honing. Some are not even jaspers at all and a few aren't even cherts, never mind the polished surfaces.


I've never paid too much attention to what separates the grains of steel from whatever's being sharpened, but assume that either through adhesion or some other mechanism, molecules can be removed without slicing them off in bits.
Yes, the metal is sheared or pulled from a tool edge in more than one way, but by what mechanism it's removed by various cherts and other hard natural stones I can't say. I just don't know. Under my engraver's microscope, it appears there is some shearing and some smearing action in novaculites and jaspers alike, but it's hardly conclusive, just looks to be so. I'm far from expert in such matters as most of my knowledge of abrasives and abrasive action is practical, at best. I'm just happy if metal or gem material is removed while leaving the best surface possible.

I've found nicely-sized slabs on eBay for ten dollars, right. The thing is to avoid pits and actual fractures (some brecciated fissures are not fractured but appear so), simpler patterns are generally to be preferred over brecciated, orbicular and so on, and stick to established well-known named varieties such as Biggs, Willow Creek and so on. Finally, some slabs called jasper are anything but, so Google or ask if you're unsure.

If you prefer rectangular to free-form, a tile saw with a continuous rim diamond blade should do the trick. If I ever get my hands on a slab saw again, I'll send samples of several jaspers and cherts with interesting abrasive qualities.

If loading becomes problematic, diamond will clean and refresh jasper just as it does hard Arkansas.

[Harold Burrell]

Forums certainly drive purchasing.

See? Now my wife is going to read that...and then ground me from coming here.

Especially since...just this week...I placed another order with Stu...:o

[Chris Griggs]

Especially since...just this week...I placed another order with Stu...:o

May I ask for what?????

[Steve Friedman]

David,

Thanks for that explanation. Starting to make sense.

Even if the Spyderco medium and fine stones were perfectly flat from the factory, they would still need some flattening at some point during their lives. It seems that I would be altering the factory grind if I did that and it seems that altering the factory grind will make the stones less abrasive. So, how would you flatten the Spyderco medium and fine stones without making them less abrasive? Not an issue on the Ultra Fine, since I don't mind that stone having a higher effective grit, but I wouldn't want to make the medium or fine stones any less abrasive. If anything, I would love to be able to make the medium even more abrasive.

Since I use honing guides, flat is important.

I am glad to see another endorsement of the EZ-Lap diamond plates for steel and may try those. I had sworn off diamond stones for steel after bad experiences with DMTs and was going to buy some Atoma plates just to use for steel. But, after reading your (and the other David's) comments, I am definitely inclined to give the EZ-Laps a shot. The price is certainly right.

Thanks again,

Steve

[Harold Burrell]

May I ask for what?????

Just because I wanted to. :p

[Chris Griggs]

Just because I wanted to. :p

Ahhh your no fun...fine keep your secrets about your new toys for now...but I want to see pics when they arrive. :)

[David Weaver]

Dave B - I went cheap and knocked out two fairly boring pieces of maybe jasper on ebay. For the most part, they don't appear to have much on at least most of the stones that would constitute pitting, cracks or voids. There was a lot of extremely interesting stuff out there on google slabbed thing (presumably to make jewelry), but a super colorful varied stone would probably have less chance of being consistent and it would also obscure what was going on.

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281108532457

The second will have to be put into plaster since the back is extremely rough, but I don't care about that.

Lots of pieces of various cherts, but big cheap ones are harder to find.

[Harold Burrell]

Ahhh your no fun...fine keep your secrets about your new toys for now...but I want to see pics when they arrive. :)

OK, OK...I'll tell you...

I ordered a Sigma Power 1200 and a 6000, a Shapton Pro 1000 and a 12000, an i-Wood 300 diamond plate and...a rubber base.

I should be set for a while. :)

[Chris Griggs]

I should be set for a while. :)

I don't know about that. I think you're gonna need to order a handful of various new edge tools as well to justify the stone purchases. I bet Stu would be willing to sell you some nice chisels to go along with those new waterstones.

[Harold Burrell]

I don't know about that. I think you're gonna need to order a handful of various new edge tools as well to justify the stone purchases. I bet Stu would be willing to sell you some nice chisels to go along with those new waterstones.

Oh, man...SHUT UP!!!

That's all I need...one more voice in my head...

They call to me...

I hear them even now...

"Buy me...you know you what me...Do it...Do it..."

AHHHHHHHH!!! :eek:

[Chris Griggs]

Oh, man...SHUT UP!!!

That's all I need...one more voice in my head...

They call to me...

I hear them even now...

"Buy me...you know you what me...Do it...Do it..."

AHHHHHHHH!!! :eek:

Mwahaahahahahahahahahahah!

[David Barnett]

I went cheap and knocked out two fairly boring pieces of maybe jasper on ebay. For the most part, they don't appear to have much on at least most of the stones that would constitute pitting, cracks or voids.

You did well, I'd say. Both are large enough and the surfaces look to be sound. I'm eager to see how they'll perform. And cheap is good. Cheap is very, very good.

The heels on my vintage water-quench carbon steel square (diamond-shaped) and onglette gravers are about ¼mm long and I was impressed at how flat and highly polished they were compared with my very old black trans Arkansas, other trans Arkansas stones, the Spyderco and ½µ spray diamond on Raytech ceramic.

What's most surprising are the HSS square gravers I use for high-karat gold, as these must be well-polished to avoid any gold sticking to them as would happen with plain carbon steel. No, not as polished as diamond on ceramic, but doable. The bright surface smoothness of both high-carbon and HSS may confirm your idea that there may be more than simple shearing at work. It does appear more burnished than from my hard trans Arkansas stones. Beilby flow? Who knows.

I do have one smallish slab of gemmy Marlborough chrysoprase that I'm sure does what it does more by burnishing with very little metal removal, hardening and consolidating rather than shearing. It will eventually develop a shiny patina of steel particles in the most used areas, so at least some metal is left behind, but its use is limited.


Lots of pieces of various cherts, but big cheap ones are harder to find.

It helps to know lapidaries who will cut the boring cherts less desirable for jewelry. My problem is I already have too much and with the exception of certain jades, I rarely carve opaques.

[David Barnett]

Thanks for that explanation. Starting to make sense.

You're welcome. It's not exactly intuitive.


So, how would you flatten the Spyderco medium and fine stones without making them less abrasive? ... If anything, I would love to be able to make the medium even more abrasive.

I've had my Spyderco stones for way longer than I care to think about and haven't felt the need to flatten them, but they're neither my only nor primary hones so you may arrive at such a point far earlier. By the time that happens, there will likely be new technologies to supplant ceramics or at least, to maintain or restore them, but if we are to limit ourselves to the present I'd say diamond is probably best.

If you've dished your ceramics to the point they need to be flattened you'll have already worn away any original surface characteristics so I'd think there'd be little reason to avoid using diamond to reprise flatness and cutting ability.

My inclination would be to use diamond only somewhat coarser than the stone's own coarseness. If this fails to bring back some cutting life, I'd likely try an even coarser grit. Perhaps David W or someone else will have something better to offer but that's how I would approach it.


Since I use honing guides, flat is important.

While I mostly free-hand woodworking tools, I do use honing guides and jigs on narrower chisels and gravers with special geometries. Either way, I want flat.


I am glad to see another endorsement of the EZ-Lap diamond plates for steel and may try those.

I've tried quite a few electrobond diamond products over nearly two decades and the Eze-Lap 600 is my only choice for woodworking. In fact, I'm entirely satisfied going from grinder to the Eze-Lap to 1µ diamond paste on cast iron for everything with an occasional oxide stropping for paring chisels and smoothing irons, my routine since the late '90s. Sure, I'll experiment and tinker with other abrasive systems for fun or from curiosity, but I always return to my simple regimen for woodworking.

I avoid all diamond laps with interrupted, that is, noncontiguous diamond surfaces—I don't like dots, whether surrounded or covered with diamond—and have no use for DMT stones or pastes whatsoever.

[David Weaver]

I don't have any great suggestions. I only suggested coarse diamonds to try to avoid grading the stone, plus they are nice to have around even if you do have a good medium stone. It's hard to find anyone who has used the spydercos too much, though I know george settled on them after trying a lot of stones in the 1970s. The knife folks like them a lot, and from time to time a razor person will say something about them, but sal is correct about the razors, the strop really counts and the strop and either linen or loose fine grit setup before the final stropping have a lot more influence on a shave than does the last bench stone used.

[Steve Friedman]

I don't have any great suggestions. I only suggested coarse diamonds to try to avoid grading the stone, plus they are nice to have around even if you do have a good medium stone. It's hard to find anyone who has used the spydercos too much, though I know george settled on them after trying a lot of stones in the 1970s. The knife folks like them a lot, and from time to time a razor person will say something about them, but sal is correct about the razors, the strop really counts and the strop and either linen or loose fine grit setup before the final stropping have a lot more influence on a shave than does the last bench stone used.
David, good point. I do realize that I'm trying to use the Spyderco stones for something they were built for. I don't know about the straight razor crowd, but realize that a flat stone isn't as critical for knives as it is for plane blades (with a honing guide). I still want something harder than water stones for my carving gouges and other curved blades, and the Spyderco stones seem perfect for that purpose. If I can't get the medium stone to cut as aggressively as I want, I'll just step down to PSA sandpaper for the lower grits - or use the Eze-Lap I'm about to order.

Steve

[David Weaver]

Steve, I think they're a great choice for carving tools. I haven't used mine for straight razors so much because I fell into a vintage linen that seems to keep the straight razor sharp indefinitely. I do like the UF for anything that requires a hard stone, and I'm sure I'll like the medium, too.

I don't really have any great formed thoughts about them other than that they're a lot like oilstones, but harder and with a different abrasive. The UF is a little harder to use than a more friable stone, but if you find you like to work with a stone's attributes, it does some really nice things and you'd have to just about drop it to damage it. Plus, I never mind putting diamonds on the UF, and my favorite finish oilstone never sees that.

Oilstones are nice, but there are tools a lot of us have now that they just don't tolerate well, and I haven't had anything yet the spydercos won't cut.

[Jonathan McCullough]

Just took the DMT to flatten the medium. Took about 50 minutes. About 1/16" bow in the middle to start with. No light seepage against a Starrett rule now across all four corners. Listened to a podcast and just went at it with dish soap and water. Now have to go at the fine (not UF) stone. About the same amount of banana-ism, but this one is gonna hurt, I figure. Still and all, these should be useful. Found one of those old Prairie wet grinders at the flea market. It'd be good to have an indoor sharpening-session setup, with the oilstones out in the cold garage during subzero temperatures for touch-up on edge tools.

[David Weaver]

My medium spyderco showed up yesterday. Very close to dead flat, and the surface is in perfect shape. I don't know if it was NOS or what, and amazon dug it from the nether regions, but I was surprised.

Both jaspers also showed up, too. I will say that the one jasper hone slurried exceeds my oilstones in sharpness, and is faster. Without slurry, both are basically burnishers. That's OK, I don't mind slurrying them.

There is a catch, though, and that is that one of them varies from 1 1/2" thick to 1/4" thick on one corner, it will have to be mounted. The other is 1/4" thick, and it is fairly large so I'm contemplating what I'll do with it, as it's not thick enough to resist breaking on wood that would move at all and it's extremely hard.

Both had tiny mill marks in the surface from sawing or lapping, and both were them moderately polished. They are a bit "skippy" on clear water when they're like that with those little ripples, but it's clear to me that I will be mounting the thick-thin stone and using it on slurry a lot. It reminds me of the hardest nakayama stones, except it leaves tiny tiny very uniform scratches when slurried, but its sharpness level is describable as no wire edge on an old stanley chisel and severing hairs at a level that is at least in a class with 1 micron stones. At least as good as an excellent oilstone provides after stropping, and faster to get there (again with the catch being that the slurry needs to be there - oilstones cut fast on slurry, too, but not sharp like this).

For $10 each, I'm super pleased. If I don't get a good situation with mounting the stones, I'll just go on a mission to find a thick piece that has a flat face but that was cut without jewelry in mind.

[Paul McGaha]

OK, OK...I'll tell you...

I ordered a Sigma Power 1200 and a 6000, a Shapton Pro 1000 and a 12000, an i-Wood 300 diamond plate and...a rubber base.

I should be set for a while. :)

Congratulations on the purchase Harold. Who is that in your avatar?

PHM

[Harold Burrell]

Who is that in your avatar?

PHM

ummm...me. :o

It's part of a video that I am making for a big day at church.

[Chris Griggs]

My medium spyderco showed up yesterday. Very close to dead flat, and the surface is in perfect shape. I don't know if it was NOS or what, and amazon dug it from the nether regions, but I was surprised.

Both jaspers also showed up, too. I will say that the one jasper hone slurried exceeds my oilstones in sharpness, and is faster. Without slurry, both are basically burnishers. That's OK, I don't mind slurrying them.

There is a catch, though, and that is that one of them varies from 1 1/2" thick to 1/4" thick on one corner, it will have to be mounted. The other is 1/4" thick, and it is fairly large so I'm contemplating what I'll do with it, as it's not thick enough to resist breaking on wood that would move at all and it's extremely hard.

Both had tiny mill marks in the surface from sawing or lapping, and both were them moderately polished. They are a bit "skippy" on clear water when they're like that with those little ripples, but it's clear to me that I will be mounting the thick-thin stone and using it on slurry a lot. It reminds me of the hardest nakayama stones, except it leaves tiny tiny very uniform scratches when slurried, but its sharpness level is describable as no wire edge on an old stanley chisel and severing hairs at a level that is at least in a class with 1 micron stones. At least as good as an excellent oilstone provides after stropping, and faster to get there (again with the catch being that the slurry needs to be there - oilstones cut fast on slurry, too, but not sharp like this).

For $10 each, I'm super pleased. If I don't get a good situation with mounting the stones, I'll just go on a mission to find a thick piece that has a flat face but that was cut without jewelry in mind.

Hey that's super cool on all counts! Just don't tell the Schwarz about jasper...if he blogs about it suddenly Jim Bode and everyone on ebay will be selling "ultra rare, super minty, finest sharpening abrasive in the world jasper" at $100 per 1x4 chunk.

[David Weaver]

Yeah, it's cheap for now. It's tempting to sacrifice my 1/4" slab on some decent QS wood and see if it stays on it well and doesn't crack. It's harder than novaculite by a wide margin, so there's nothing to do with the surface other than diamond hone, but it works well as a general finisher - at least my two slabs do. I don't have a japanese finisher that cuts any finer. Here's the (maybe biggs) jasper with a little bit of darkened slurry on it. It's so uneven on the bottom that I could only use one hand to hold it and one hand on the chisel at the same time, but I'll fix that this weekend maybe with some plaster and a base.

What little I've used it so far, I wouldn't trade it for a good oilstone. With the slurry, it's faster and finer.

264688

Thanks to Dave B for bringing up the jasper and providing some advice on what type to get.

[Chris Griggs]

I think I looked at the piece on the bay when Dave B was talking about this stuff, and naming the different types to look for a couple weeks ago. I'm encouraged to know that finding a good piece isn't rocket science. I'm leaving on summer vaca tomorrow, think I'll need to get myself a piece off ebay when I get back.

You gonna try shaving off of it?

[David Weaver]

Maybe once it's settled in. It's a burnisher without slurry, but whatever it would do that an escher wouldn't, or a good coticule (which is a rare thing) ....would be erased on the linen. Good vintage linen dictates the edge.

Nearly forgot, I bought George's big frictionite pair, too. So many stones, and the linen makes it literally so that I don't need to visit a stone more than once every few months, maybe once a year.

But I do like the natural stones in the shop, and the harder the better. And this one is really something because there's no wire edge coming off the slurry and it's waxy endgrain fine with no lines or evidence of crushed grain. Great stone to use lifting the handle a little.

[Chris Griggs]

Dave, you'll have to try it out on all those different steels you have in your shop and let us know how it goes. Could be just the thing for that HAP chisel of yours.

[David Weaver]

Definitely not going to hold my breath on that. The HAP loves diamonds. It might even tolerate spyderco. The jasper might burnish it, but that's what the spyderco would do, too.

Only did the easy-sharpening stanley chisel on it so far, but will try a couple of less demanding steels. If it handles anything in the A2 range (which it should do OK with on slurry) then it's already past what you can get done properly with oilstones. Not that you can't sharpen A2 on oilstones, but there are compromises doing it and softer or carbon steels are much better to stick to with oilstones.

[Chris Griggs]

Definitely would be curious to hear how it does compared to an ark on A2 and hard white steel.

[David Weaver]

Just supposition, but it will handle white steel no problem since the abrasive is loose on the surface and since white steel never fans out much of a wire edge. No carbides in any appreciable amount, either.

Fresh novaculite is fine on the hardest of white steels. Broken in, it becomes marginal. As much slurry dulling as there is with novaculite, though, of course you want to be able to use it broken in as a final step (unless stropping with compound).

My ideal finish stone for planing is still something like a shapton, no attention paid to it and stays fairly flat but cuts everyday stuff fast. I like to have a hard natural stone nearby doing joinery, though, just preference. Certainly not necessity. It's like using a strop, except geometry is never threatened.

[Mel Fulks]

David,the slurry on the jasper,produced with diamond or what?

[David Weaver]

Yes, diamond. I would imagine if someone would've had something to abrade the jasper a century ago, they'd have been a common and favorite finishing stone.

I'm sort of satisfying my own curiosity by playing with them, I don't expect that anyone else is going to go out and buy. They fit my ideal wish list for a bench side chisel stone, though, except for the fact that it's hard to find them in a slice of any fairly large size that's also thick. That's probably owed to nobody wanting to buy a 1" thick slab to buy jewelry or to "cab" whatever that means. A lot of it says "great for cabbing" or "cabs" or "cabochons". Google will tell me what that means, I envison them in pendants.

I can't imagine anything other than diamonds would do anything to their surface, they are *hard*. I have to look at the scratches on a razor under a loupe to see what they compare to.

[Mel Fulks]

Thanks David,I thought maybe you were actually cutting with slurry from a softer stone. The cabochons usually refer to any rounded polished stone without facets.

[David Weaver]

Thanks for clarification on what Cab is mel.

I do (I guess it goes without saying) have a bunch of slurry stones, from parts of stones to "real" tomonaguras, coticule bits, etc, but this is all straight from the diamond plate. Even a diamond plate doesn't raise slurry quickly, and I'm not sure if the slurry is full grit particles or if it may in fact be broken off bits of particles that were slashed off by the diamond hone.

The reason I'm gushing about the stone, though, is that for $10, it's literally all from the stone, slurry and all, and I'm kind of shocked to be able to take an old softer chisel that raises a wire edge with anything but the finest japanese natural stone and see no wire edge off of the jasper, and even with slurry, it might be sharper than any natural stone I've seen. Maybe not finer, but very keen. The stone would be a carver's delight, and the kind of stone I like to have by for sit-down joinery (like a long row of HBDT or something) where you can rub a good quality chisel on a very fine stone after each socket or two for 10 seconds and never go back to any stones (i.e., i never have to get off my butt).

For $10, though, it's really a treat for a stone fanatic.

[Shaun Mahood]

So David W, do you think you're up for the task of clearing up all of the questions about what the Spyderco stones are equivalent to? I would really be interested, as well as what happens to them when they are flattened as far as their sharpening characteristics go.

[David Weaver]

If you really scuff up the surface of a spyderco UF with a diamond hone (or if you use it when it's brand new), it is similar to a very fast 8000 grit stone. It's very abrasive. If you don't clean it and you just use some water to keep it from getting totally blocked up with some swarf (as in, you allow the surface to break in and do nothing about it) it becomes like glass, almost a burnisher. It's hard to say what it's equivalent to at that point, because it literally doesn't cut at that point and if you'd try to hone from a 1000 stone on it or something, it would frustrate you greatly. If you clean it with abrasive cleaner like it suggests, then it ends up somewhere between those two points (in fineness and speed) unless you really really get after it with abrasive cleaner.

Not sure about the medium yet, it's brand new so it's still aggressive. At this point, it's similar in speed to a slightly finer than 1000 grit ceramic waterstone (like shapton, bester, sigma power 1200, etc).

I think most people who are not used to natural stones (which also are constantly varying unless they're just plain soft) may get frustrated by the spydercos as they change their characteristics between freshenings.

That said, if you have a diamond hone and the UF is flat to it, you can keep it fast cutting pretty easily. I'd imagine the same is true of the medium, nothing can't be cut by a diamond hone, including the surfaces of the spydercos.

[Shaun Mahood]

The spydercos can definitely be frustrating if you expect them to stay the same. I've gotten into the habit of refreshing mine with a coarse diamond stone more often, and was playing around in the last few days with rubbing my UF stone together with my medium briefly between honings and that seemed to help both of them - though it may be the placebo effect working it's magic on me.

[David Weaver]

That doesn't sound like a bad idea, actually - rubbing them together.

[george wilson]

All I do with the white stone I have is let it polish the blade razor sharp. I very seldom bother scrubbing the gray deposit off of it.

[Steve Friedman]

George,

What do you do to the medium to keep it cutting? Just powdered cleaner?

Thanks,

Steve

[Steve Friedman]

Not sure about the medium yet, it's brand new so it's still aggressive. At this point, it's similar in speed to a slightly finer than 1000 grit ceramic waterstone (like shapton, bester, sigma power 1200, etc).
Interesting.

Maybe it was wishful thinking, but the few times I used the medium, it seemed grittier than the Sigma 1200. I pulled out some old worn 2 x 6 DMT plates to compare. The Spyderco medium was definitely not as aggressive as the DMT Coarse (325), definitely more aggressive than the DMT Extra Fine (1200 grit), and probably closest to the DMT fine (600 grit). I didn't compare it to the Sigma because I was using these on carving gouges.

You have much more experience than me, so I am also curious to see what you come up with the maximize the aggressiveness of the Syderco medium. I would love for it to be as aggressive as a 600 grit stone.

Steve

[David Weaver]

Not sure if mine is different or if it's just that the surface had been polished on it as new. I've seen a lot of folks mention that stones came with big mill marks, etc. Mine came with the surface polished, but since the binder isn't solid it still cuts fine.

I have cut only with it dry so far. The UF is totally non-porous and water sits on the top. On the medium, it must be a very open structure because the water just disappears like it would on a bester.

It'll be interesting to see how it cuts after it's been used a while, I wouldn't mind if it opened up a little if the polish gets knocked off of it. I like it.

As it is right now, though, it polished a semi-hss chisel a little bit (not a bright polish) from what it looked like coming off of a 1200 grit ezelap, but that might have been the steel, which doesn't really agree too well with ceramic abrasives.

[David Weaver]

Dave, you'll have to try it out on all those different steels you have in your shop and let us know how it goes. Could be just the thing for that HAP chisel of yours.

No A2 yet, but I did put one of the koyama SemiHSS chisels to jasper last night. The ultimate result was still no wire edge and hair shaving, but it didn't like the chisel!! The cut rate is probably a fifth of what it would be with US vintage carbon steel, but is doable if the chisel is set on diamonds and then only the very edge of bevel is worked.

Of course, three swipes on the shapton do the same thing. This jasper is likely better kept for stuff that's not too alloyed. If the semi-HSS can't be done easily, it won't touch the HAP. The semi-HSS is about twice as stubborn as A2 on everything else, but not as gummy as the mujingfang HSS.

[Steve Friedman]

I just received a used Shapton Pro #1000 and thought it would be a good opportunity to compare it to the Spyderco medium stone. So, this morning I took a large (40mm wide) carving gouge and sharpened it on both stones. I know it's comparing apples and oranges. My first reaction was to remember why I like waterstones so much. The feedback from the Shapton was incredible. I could feel the stone cutting the steel. There was almost none of that feel with the Spyderco. My other impression was that the Shapton cut much more aggressively than the Spyderco. It may be that flattening my Spyderco made it less aggressive or just the nature of the beast, but the experiment certainly reinforced the benefits of using waterstones.

I am still concerned about ruining my waterstones if I use them to sharpen carving gouges, so I still want to make the Spyderco stones (or diamond plates) become a workable solution. Of course, I still haven't tried oil stones, but I really don't have any desire to amass a stone collection as large as some of you have.

Steve

[David Weaver]

I don't thing anyone should amass the gluttonous pile that I have unless they have some sort of curiosity with them or fascination with edges and the history of making them. What other sucker other than me would actually buy some of George's old frictionites that didn't sell at auction on ebay (and in the interest of full disclosure, I paid what the proceeds of the sale would've been if the stones actually sold). I love the frictiontes....ok...getting off topic already...anyway.

I hope it never comes across as I think people should feel obligated to buy more than one good set of stones.

All of that said, I love the shapton pro 1000 (and the SP 1200 and the bester 1200 - all three of them feel like they're filing the steel away). that's one of the stones I was thinking of when comparing fineness of the 1000 stones vs. the spyderco medium. But it is really hard to tell how deep and drastic the grooves are without going to a loupe.

I could get by with the medium spyderco as it is thus far just fine, though, I'd just visith the grinder a little more often and work smaller flats....and that's not a bad thing.

[george wilson]

If I'd known how expensive fractionate stones would become,I'd have bought them by the gross!!

[David Weaver]

George did give me a coticule, though, that's the other end of the full disclosure.

George, you should've cleaned out the CW warehouse when you retired, before any more of those frictionites were sold. I've seen a price list for their stones before, and it's not hard to figure out why they didn't care if they made any more stones once their abrasive supplier went out of business. They were like 5 bucks each in the 70s, couple bucks more for some and couple of bucks less for others. Now, every axe man in australia wants one. Between those and the norton "axe man" razor hone, there are some nutty values for small razor hones, they just aren't being paid by anyone shaving their faces.

Speaking of frictionite, there was someone on the razor board who found a whole box of the big #00 frictionites (the bench stone sized ones). I have no idea what he ever did with them, they were NOS and unopened.

[george wilson]

We used to be allowed to purchase personal use items from the warehouse,but that,along with many other employee priviliges over the years vanished.

[Joey Naeger]

Just to get back on topic, I was able to successfully lap one of the medium stones flat in maybe 10 minutes using loose SiC on a glass plate. It was noticeably out of flat. I'm sure a fine stone will take a lot longer, but I think it will still be manageable. The lapped surface is pretty aggressive, but I think it will break in a little bit.

[Steve Friedman]

Just to get back on topic, I was able to successfully lap one of the medium stones flat in maybe 10 minutes using loose SiC on a glass plate. It was noticeably out of flat. I'm sure a fine stone will take a lot longer, but I think it will still be manageable. The lapped surface is pretty aggressive, but I think it will break in a little bit.
That's a good idea. Did you use water or oil or did you do it dry?

Steve

[Joey Naeger]

Water and a fair bit of pressure. The grit broke down quickly so it needed to be replenished frequently.

[Joey Naeger]

An update for any who are interested. I've acquired a fine stone as well and went through the process of flattening it on a glass plate with SiC. What I found with both the medium and fine is that the lapped surface was actually convex. I'm not sure exactly what caused this, but I took both stones to a coarse diamond stone and corrected it. I found it easiest to do with no water and occasionally wiping the dust off the diamond stone. Now that both stones are truly flat, I think they are excellent sharpening stones. I really enjoy using them for gouges and other tools that I've found difficult to control on waterstones. They have a hard surface that gives you a feeling of clarity when you're holding your bevel flat. I believe someone who sharpens a variety of tools freehand will find these to be rewarding stones to use.

[David Barnett]

What I found with both the medium and fine is that the lapped surface was actually convex. I'm not sure exactly what caused this, but I took both stones to a coarse diamond stone and corrected it.

This can happen with too much grit on a hard lapping substrate. It can happen with too much grit on a cast iron lap, as well, but the cast iron lap will generally work faster and grind flatter when the right amount of grit is used due to cast iron's advantage in abrasive embedment and presentation.

Getting the correct amount of abrasive, which often means the least quantity of grinding medium, on glass or ceramic laps is a technique that takes time to learn, such as charging a ceramic lap with submicron diamond. Cast iron is more forgiving.

Glad you finally improved your Spyderco stones to your liking.