Water Stones

Re: Indeed, most informative  However....

wilbur

"Buyers of industrial grinding wheels demand this information; woodworkers don't. It is pointless knowing the tool is A2 and not knowing what abrasive particle is trying to scratch it, or not."

Seriously? There's a very good reason why woodworkers may not be all that interested in the composition of waterstone abrasives. It's because they are most likely dealing with a much narrower range of steels than the buyers of industrial grinding wheels. If all you need to deal with is O-1 or A-2, then that's a pretty narrow range of variables.

And the identity of the abrasive is not the only thing that needs to be known. The binding matrix should also be identified, so that how quickly new abrasive is exposed by the matrix can be known. That's assuming that you can make some sort of conclusion about the waterstone's behavior can be made by this information.

Since most woodworkers are only dealing with a couple types of tool steel, I have a very hard time believing that you can't come to some sort of conclusion regarding a waterstone's performance based on other's experiences even if the exact composition of the waterstone abrasive is unknown. You can do tests like the one in FWW, or the ones that are available on the Tools From Japan blog for information, and that information is probably good enough for woodworking purposes.

If we are going to pick on the unknown components in our sharpening media, then you might as well say that you shouldn't use diamond plates because it's not well known exactly what adhesive was used to adhere the diamonds to the plate. As others have mentioned in this thread, diamond plates are prone to having the diamonds come off the plate over time. By your logic, not knowing how the diamonds are adhered does not allow me to predict how long such a plate will last, and therefore diamond plates would be beneath my notice, much as you seem to categorize waterstones.

As I understand it.....

Bill Tindall

Hardness is determined by seeing how much a diamond point sticks into the steel. I am not sure whether the following is an accurate analogy or not. The steel is like the water stone in that there are hard abrasion resistant particles (carbides) dispersed in a matrix of softer metal, iron. If we were to stick a point into the water stone it would be the hardness of the binder that would determine penetration, not the abrasive particles dispersed within the clay(presuming the hard particles were at modest concentration relative to the clay binder). Ditto for the steel. The penetration of the point is determined by the hardness of what ever crystal forms of iron are present. The point doesn't penetrate the hard carbides present at modest penetration, it just pushes them aside. Hence, the presence of a modest concentration of carbides does not affect the hardness as it is measured.

However, when the steel is rubbed (abraded) it is the modest concentration of the hardest particles(carbides) that resist its wearing away. The abrasion resistance does correlate with the concentration and composition of the carbides present. Iron carbides are much softer and hence less abrasion resistant than the carbides of the alloying elements.

We know that hardness does not strongly correlate with abrasion resistance of steel alloys. Compare a carbon steel with the series of steels that have increasing vanadium content, all at the same hardness. Something like M4 is vastly slower to abrade than a carbon steel, with steels like A2 and 3V falling in between.

Re: Indeed, most informative  However....

Bill Tindall

Aren't there all sorts of discussions about dealing with the fact that A2 is more difficult to abrade(sharpen) than carbon steel and we are soon to be facing an even more abrasion resistant steel offering? Haven't we been told that for unknown reasons this or that stone abrades A2 better or worse. I'll bet I could have predicted the result if I had the same information I have for wheels.

When I select a grinding wheel the code tells me the hardness of the binder, as well as the abrasive composition and its friability. From this information I can determine the wheels suitability for the tool I need to abrade. I know this same information for fixed diamond plates (whether it is single crystal or not tells me about friability). In fact the only abrasive stones where the manufacturer doesn't reveal this information is water stones. I could use this information if it was provided the same way I use it for wheels. I would not need to wait for a review in FWW to make an informed choice.

(Message Deleted by Poster)

Newbie Question

Howard

I’m new to sharpening. From Rogers’s initial question can I assume that A2 blades cannot be sharpened using the MKII system?

Thanks

Howard

Re: Newbie Question

Howard

Mistake on my part, I thought he was talking about the MarkII Power Sharpener

Re: Newbie Question

roger lance

Howard....just to clarify, Lee Valley sells a sharpening jig called the Mk II honing guide that simply holds plane irons and chisels at various angles for sharpening on a water stone or other sharpening plate/stone/surface....this jig retails at about $65....Lee Valley also sells a sharpening motorized machine/system that they also call the Mk II....it retails for about $400....I was referring to the Mk II honing guide....A2 irons can be sharpened using either product....in the case of water stones, some stones are more effective at sharpening A2 than others....the subject of sharpening is confusing and unfortunately, some people seems to make it more confusing than is necessary.

Re: Indeed, most informative

Pam Niedermayer

Some of these water stones don't have any matrix, they're all abrasive, sintered.

And some of them are ceramic, whatever exactly that means, but I would expect matrix to not be a big deal.

And then I suspect that it matters a lot as to how these materials are combined. For example, in some cases a lot of the matrix is lost in the combining, resulting in a higher percentage of abrasive that the stone started with.

Not being a materials engineer, I feel a lot more comfortable relying on empirical results with the steels I use than some list of materials.

Pam

Re: A question for water stone enthusiasts

Pam Niedermayer

Check out Stu's site, Tools From Japan, for Atoma and iWood diamond stones. Also, So at Oz sells Atoma. I suspect many other places also sell the Atoma.

Pam

Re: Diamond 'binders' more alike than not

wilbur

Hi David,

I think my analogy completely holds. The assertion was made that the only way of determining performance is to know the component involved in that aspect of performance. In the case of waterstones, the question is if waterstones will effectively sharpen more abrasive resistant tool steels, and the apparent answer is that identifying the abrasive used will predict its performance.

In the case of diamond plates, the question is how long will diamond plates last before loss of diamonds from the plate renders the plate ineffective. The apparent answer would be knowing the composition and method of the adhesion process would predict performance in this aspect.

My point is that if we are going to pass on waterstones because we don't know the composition of the abrasive, then we should pass on diamond stones because we don't have all the details on the adhesion process. To me, both conclusions are equally silly, especially since there are other ways of getting the information that we really want even though we have other methods of getting the information that we really want (which waterstone do a good job on A-2, and which diamond plate lasts the longest). If Stu reports that Brand X waterstone does well with A-2, and if you or Bill tell me that Brand Y diamond plate lasts longer than the others, I'm good with that, even though I don't know the exact components that are leading to good performance.

Re: Indeed, most informative  However....

wilbur

Hi Bill,

That's the problem with being an early adopter. There's another way of dealing with not knowing what sharpening method to use with these newer abrasion resistant tool steels. Don't use them, at least not until those methods are sorted out. I'm sure there are other tool steels that are suitable for woodworking where the method of sharpening isn't such a mystery. Having seen your output, I know you know such tool steels exist as well.

Re: Diamond 'binders' more alike than not

Pam Niedermayer

My point is that if we are going to pass on waterstones because we don't know the composition of the abrasive, then we should pass on diamond stones because we don't have all the details on the adhesion process. To me, both conclusions are equally silly, especially since there are other ways of getting the information that we really want even though we have other methods of getting the information that we really want (which waterstone do a good job on A-2, and which diamond plate lasts the longest). If Stu reports that Brand X waterstone does well with A-2, and if you or Bill tell me that Brand Y diamond plate lasts longer than the others, I'm good with that, even though I don't know the exact components that are leading to good performance.

Exactly, and especially since sometimes, even when we know the material composition, we don't know whether they were combined in a way that handles sharpening steel with aplomb without the testing.

Pam

Correlation

Warren in Lancaster, PA

At a given hardness, different steels have different abrasion resistance. But, nevertheless, hardness of steel correlates very well with abrasion resistance. For a given steel, the harder the steel the more resistance to abrasion. Annealed steel abrades easily.

Historically the abrasive was silica and the matrix clay. What historical era and what continent are you talking about here?

Re: Water Stone Flattening

Brian Greene

I'm mindfull about contamination but I see no reason to be obsessive about it. I rinse my stones as I'm lapping. I'm also careful to rinse the blade between stones so as not to spread the grit around where it doesn't belong. Honing guide users (I'm not one) should also be careful on this score.

In my experience as a teacher of sharpening and having counseled hundreds of customers at the counter and at trade shows, it seems to me that the number one problem people have with sharpening is not lapping stones properly. They must be flat for the way most of us sharpen and being obsessive about it doesn't require much time or effort.

"ceramic" tells me a lot....

Bill Tindall

I suspected that the modern high performance water stones were likely "ceramic" or "seeded gel" aluminum oxide. This relatively new material is used in the high performance grinding wheels. The "3X" wheels have 30% of this high performance expensive to make abrasive. It has the property of fracturing to yield new sharp edges without significant loss of particle size. The new edges means the dull particle doesn't need to be shed/replaced by a soft matrix/binder like in a conventional abrasive format. The result is that one can make a harder stone that wears slower, yet it still cuts fast because of cutting edge renewal resulting from particle surface fractures.

Re: "ceramic" tells me a lot....

Pam Niedermayer

The result is that one can make a harder stone that wears slower, yet it still cuts fast because of cutting edge renewal resulting from particle surface fractures.

And that's what the tests reveal, with some of these even handling powdered metal edges pretty well.

Pam

Re: Water Stone Flattening

Derek Cohen (in Perth, Australia)

Hi Brian

I would qualify your statement about stones needing to be flat to refer to honing guides. A stone, worn to a gradual arc over time, will contain enough "flat" to hone a bevel if it is freehanded. Of course, there is still an arc, which must create a rounded bevel (no how small) but the hand can often accommodate to this - and I believe this was the case when oilstones ruled. On the other hand, when a honing guide is used on this surface, the extended length created by its body and roller will effectively accentuate the arc. Honing becomes significantly more difficult on such a surface.

After writing all this I do think that the issue is a moot point - I choose to flatten my Shaptons even though I mostly freehand blades because doing so also cleans the surface of the stone and enables it to function optimally.

Regards from Perth

Derek

Re: Water Stone Flattening

David Charlesworth

Derek,

I would suggest that waterstones are kept flat during back preparation of new tools and final back polishing.

When doing a lot of planing I will often allow the 800 stone to wear hollow, as this is helpful for producing cambered blades. But I never allow the polishing stone to become hollow.

There has been some misleading discussion of hollow oilstones and convex bevels recently. A convex bevel may be fine, but there was no mention of the menace of a bellied back!

best wishes,

David Charlesworth

Re: Water Stone Flattening

Derek Cohen (in Perth, Australia)

Hello David

How wonderful to see you back in the saddle! You had us a little worried for a while back there.

Yes, I see the benefits of a hollowed 800 for creating a camber. I recall Odate designing a diamond stone for that very purpose. However I prefer the predictability of cambering "by numbers" on a flat stone.

The importance of a flat stone for working the back of blades is very relevant. These days I would rather use diamond paste on caste iron for the coarser grits. This is much more reliable at that end of the waterstone grit spectrum, where stones tend to be soft and dish easily. I keep the 12000 Shapton very flat because that is the only waterstone that touches the back of a blade.

Anyway, it is good to know you are on the mend. My best wishes for Christmas and the New Year.

Regards from Perth

Derek

Affirmed, Thom, but are the Kings

Tom Colligan

adequate for A2 steel? It's been my understanding that something harder is needed in a stone matrix than the normal Japanese waterstone. Tia, Tom.

Re: Affirmed, Thom, but are the Kings

Bruce, a MN Galoot

I have kings, mostly, and two a2 blades. The kings work but not easily.

Fantastic read

Archie

Fantastic series of posts here. Though I could add my experiences and opinions, you folks have genuinely addressed the issues. I hope everyone who needs this info can find it. Fantastic!