Soft VS "Hard" (not True Hard/Black/Transluscent) Arkansas Stones

[Luke Dupont]

This is one of those "is it just me, or..." posts -- something I've always wondered about but never seen discussed.

So, I've used a ton of Arkansas stones. They're my go to, and my favorite sharpening media. However, I've always felt that the Soft Arkansas is kind of the worst of the bunch.

It seems to me that the "Hard" (usually white, though Dan's come in all kinds of colors) variety is almost as quick as the soft... sometimes, I would swear, even quicker, and doesn't clog or get burnished nearly as bad. And yet, it produces a much finer edge. It's actually a surprisingly quick stone that can take out deep scratches left by a coarse diamond plate, and yet leave you with a really keen edge. I've got tons of stones that leave a similar finish, but can't do that. It seems unusually fast for its grit compared to the Soft, and, indeed, to many other stones natural.

I've always wondered if it was just me who notices this and thinks so, or if others feel the same. My go to these days, if not a Washita, is just an India and a "Hard" Arkansas, followed occasionally by a strop or black/translucent, depending on whether I really need that extra sharpness or not.

[Tom M King]

The only Soft I've ever used was in the set of four stones I bought 47 years ago. I agree with everything you said about yours.

The first stone in that set was named Washita. It is a purplish, variegated colored stone, much like the ones that were re-released a year, or two ago, and a wonderfully fast cutter. I went from that Washita, straight to the White Hard stone. The Soft seemed like a waste of time.

[Cassius Nielsen]

I know Japanese natural stones from sharpening knives. It is a whole rabbit hole to go down but some stones are just better than others. Without trying them out it is hard to get an idea what the stone is like. Some soft stones will be amazing and bring you up to 5 or 8k grit from a synthetic 1k depending on how you work the slurry. A medium stone that will work from 1k-8k grit is a treasure in my book. On the other hand finding a hard stone that will work from 5k up to who knows what grit with some slurry is also not an easy find. What I learned from using natural stones is that once you have one or two that work the way you want with the steel that you have, stick with them. The next best thing might be total crap for the steel you put on them.

[Rafael Herrera]

My understanding of these stones is that the difference between the hard and the soft Arkansas is in their compactness (measured by their specific gravity). The size of the particles making up the stones is the same, it's the spaces in between these particles that causes changes in the density of the stone and is directly related to their abrasive properties. As an aside, a good Washita is in the lower range of compactness. How abrasive any sample you have may vary depending on the specific gravity of the stone, a soft Arkansas may get glazed sooner rather than later and stop cutting, a hard Arkansas may not get glazed as easily and continue cutting.

I have one Washita that works really well on my tools, whereas other samples don't cut as well, they feel too "hard". I also have a Dan's black Arkansas that I rarely use, stropping or the powered buffer achieves the same effect for me for final honing. I have also tried vintage translucent Arkansas, they're cool, but not necessary for my bench work.

[Warren Mickley]

I have used a soft Arkansas stone on every tool I have sharpened since 1983. Before that I just used a Washita and a black Arkansas. I use it in a worn smooth condition; I do not abrade it to roughen it up. I would buy another if this one broke.

There could well be quite a range of what is considered soft Arkansas. If someone had a hard Arkansas at the lower end of density and a soft Arkansas at the upper end of the density range, they might not be very different. I think one would have to go through a lot of stones to really get a feel for this.

[Jim Koepke]

[edited]
There could well be quite a range of what is considered soft Arkansas. If someone had a hard Arkansas at the lower end of density and a soft Arkansas at the upper end of the density range, they might not be very different. I think one would have to go through a lot of stones to really get a feel for this.

Agreed, of my stones from Dan's Whetstones one is labeled soft Arkansas and another is marked hard Arkansas. There is a difference between the two, but not a great deal of difference.

Other supplier's stones labeled simply Arkansas stone have been softer or more aggressive than the Dan's soft Arkansas stone. These have been more like my stones that came labeled as Washita stones many years ago.

There are also a few modern stones labeled as Washita stones that do not cut like my older Washita stones. One from Norton recently sold as a Washita comes the closest. It may be from the end of the particular area's last Washita stones.

jtk

[Rafael Herrera]

I have used a soft Arkansas stone on every tool I have sharpened since 1983. Before that I just used a Washita and a black Arkansas. I use it in a worn smooth condition; I do not abrade it to roughen it up. I would buy another if this one broke.

I don't remember seeing any soft Arkansas in the vintage market, I'm curious to try them. I ordered one from the Natural Whetstone Co.

This is an interesting read regarding how these stones where marketed in the early 1900s, https://babel.hathitrust.org/cgi/pt?id=uc1.31175035165789

Rafael

[Eric Rathhaus]

I have a Pike's Lily White that is labeled as soft and as a Washita. It was unused when I got it and cuts fairly aggressively, definitely the first stone to use unless you're reshaping your bevel or another procedure that requires significant material removal.

[Rafael Herrera]

I have a Pike's Lily White that is labeled as soft and as a Washita.

Washitas were a class of their own, further graded as hard or soft. They were mined in very specific quarries as well. The soft ones are the ones to definitely look for, those are the ones they will cut more aggressively.

Arkansas stones were also graded as hard and soft, but they were differentiated from the Washita stones.

The pamphlet I linked above has some of that info. A lot more detail can also be found in this old report, https://babel.hathitrust.org/cgi/pt?id=hvd.32044102940343&view=1up&seq=135&skin=2021. The link takes you to the sections discussing the Washitas, but there's a lot more to know in the rest of the document.

[Jake Hillestad]

Washitas were a class of their own, further graded as hard or soft. They were mined in very specific quarries as well. The soft ones are the ones to definitely look for, those are the ones they will cut more aggressively.

Arkansas stones were also graded as hard and soft, but they were differentiated from the Washita stones.

The pamphlet I linked above has some of that info. A lot more detail can also be found in this old report, https://babel.hathitrust.org/cgi/pt?id=hvd.32044102940343&view=1up&seq=135&skin=2021. The link takes you to the sections discussing the Washitas, but there's a lot more to know in the rest of the document.

Washitas are a dirty little rabbit hole I've fallen down. Only way to have a reasonable idea what you're getting into is to buy a labeled one which are now stupid expensive. Currently running through about half a dozen unlabeled stones trying to figure out which are going to do what I want them to in the long haul.

Regarding the hard vs soft, I've also not found a lot of difference. In fact, I have a single vintage soft I keep around for nostalgia sake only. Everything I sharpen these days is off a Washita straight to a Translucent. Works for me.

[Warren Mickley]

A few notes: Some people are abrading their Arkansas stones supposedly to "expose fresh grit". What they are really doing is making scratches on the surface, and this rough surface is what is doing the cutting. In that case an abraded hard Arkansas might not be much different than an abraded soft Arkansas. A soft Arkansas that is well broken in and not abraded might give a better polish.

[Eric Rathhaus]

Warren, you would still abrade an older stone to bring it back to flat, no?

[Warren Mickley]

My black Arkansas is 45 years old. It has not been abraded since it left the factory and it is now 1.000 inches thick, same as ever.

The Washita stones do wear. I use one side for gouges and small tools. It is quite dished. The other side I use for wider chisels and plane irons. On that side I sharpen with part of the tool overhanging the edge of the stone so that I get even wear on the stone.

The soft Arkansas stone wears slowly. Mine is dished about .001. It would be worse if I did not take care to even out the wear.

[Eric Rathhaus]

I have a couple of old stones I acquired on a bundle and none of them are flat. I just wondering would you try to make them flat or use as is?

[Jim Koepke]

I have a couple of old stones I acquired on a bundle and none of them are flat. I just wondering would you try to make them flat or use as is?

A couple of my softer stones had become dished over the years. With a bit of care and thought put in to how to accomplish the desired end they were used against each other to bring both of them to useable flat stones.

You might want to wear a mask while doing this. Even with oil on the stones there may be some dust you do not want to breath.

jtk

[Andrew Pitonyak]

I have a couple of old stones I acquired on a bundle and none of them are flat. I just wondering would you try to make them flat or use as is?

Although I spent significant time looking at how people recommend flattening Arkansas stones, I have never done it myself because none of my Arkansas stones are out of flat and the ones that I did buy that were out of flat turned out to be misrepresented and were not Arkansas stones and not worth flattening.

It was my intent to to use loose carbide on a glass plate to do it (with water), but I have seen (in videos) people do it on concrete. If mine were out of flat, I would start with one to see how it went and go for it. One concern is that you are indeed introducing scratches and then the question becomes, how fine should you go after flattening the stone. I know that for a while, it was recommended that you purchase a nice Washita stone and then lap the two different sides at different grits so that they would cut differently. So, understand that if you do lap these stones, you may end up changing the cutting characteristics. I have zero experience with this, it is just something that I expect to happen. This was mentioned in passing in a previous post.

"Best Arkansas Stones" (A brand / company) looked at scratch patterns to find equivalent "micron" sizes for their stones (this is or was on their web site, no idea if it is still there), but, they claimed



soft = 12 micron = 1200 grit
Hard = 10-11 Micron = 1500 Grit
Black = 7 - 7.5 micron = 2300-2500 Grit
Translucent = 5.5-6 micron = 3500-4000 grit.



I should use the "approximate" symbol rather than the "equals" symbol, but it is not on my keyboard and the non-scientists or mathematicians in the group probably prefer to see =.

I do own a sets from Preyda, Dan's, and Best. Nobody agrees on "equivalent" grit. Preyda claims:



Soft = 400 - 600 grit
Hard = 600 - 800 grit
Hard Black = 2000 - 3000 grit
Translucent = 4000 - 6000 grit
Surgical Black = 8000 - 1000 grit


Then Dan's steps in and says (listed in order of what they think will leave the finest edge):

Soft = 400 - 600 grit
Hard = 600 - 800 grit
True Hard = 1200+ grit
Translucent = 1200+ grit
Black = 1200+ grit


Preyda and Dan's both agree that their finest stone is not the translucent. I own only a few translucent stones.

I have had good luck with all of these stones but the general consensus seems to be that Dan's is the fastest cutting (or maybe the best) but I am in no position to agree or disagree with that since I feel that I have too little experience to say this. I have, however, managed to get good results from all of these stones. Initially I had poor luck with my Best stones so I bought some Dan's stones and received advice here on how to use them and then I started seeing good results from all of them. Oh, I have also had pretty good luck with a stone that I accidentally purchased that the seller called a Washita but does not look like any washita I know. It seems to cut similar to what I expect from a Washita. I realized immediately I had purchased the wrong stone but it is one of my favorites; go figure!.

[Luke Dupont]

You can flatten softer Arkansas stones with a diamond plate, but it will wear out over time, and it will wear out VERY quickly if you try to flatten a transluscent or surgical black.

A very easy solution is to take two coarse (india or carborundum for example) stones, rub them together to make them flat, and then rub them on your Arks. I usually do this with a coarse india and it seems to work just fine, even for the hardest arks.

Sand paper on a flat surface, or better yet silicone carbide are options as well.

The stone will initially cut more coarsely after this, but it will quickly wear back into its natural grit if you sharpen often.

I find that I like to leave my surgical blacks with scratch patterns straight from the coarse or fine side of the India, though... Something about a scratched up surgical black allows it to cut faster but still fine, and I think there are a number of other people who notice the same thing.

As for grit and the edges left by Arks, you can't really equate scratch patterns and grit to edge fineness, because arks cut very, very shallow grooves -- much shallower than a diamond plate or man-made stone.
So, even if a Soft might technically be something like 400-600 grit, the edge you get is going to be *MUCH* finer than that, and the cutting speed equally slower -- more in the 1500-2500 range for a Soft Ark in my experience. And I'd put a Hard at more like 3000-5000, with the hardest and finest Arks being well above 10k in "effect". But there is no equivalant grit, really -- they cut differently and leave a very different edge compared to any synthetic stone, and even to many other natural stones. Taking a blade to a bare leather strop reveals just how fine an edge Arks tend to give, as the shallow scratches can be easily refined on just plain leather.

[Rafael Herrera]

I tried lapping a Washita stone using sandpaper and it took a long time. It also created a lot of dust that it was probably pretty bad to breath. A diamond stone may also take a long time and the stone may end up worn out.

Lee valley sells silicon carbide lapping grit. The coarse powder, 90 grit, on a piece of float glass and water will wear any stone very quickly, not just a Washita. For finer stones, 180 grit will smooth the surface.

It's nice to refurbish an old stone and fit it in a new box.

465540

[steven c newman]

Hmmmm, with all this constant sharpening...where does one find the time to actually USE the tools? Is there any shop time left to work on a wood project?

I usually schedule a day between projects, to refresh edges. Just normal maintainence....usually am doing any rehab work at the time, too.....while waiting on the next project to start.

IF I do stop during a project to refresh an edge...usually only 10 minutes, then back to work. YMMV:D

[Andrew Pitonyak]

Nicely stated Luke, thanks, lots of information there.

[Andrew Pitonyak]

Hmmmm, with all this constant sharpening...where does one find the time to actually USE the tools? Is there any shop time left to work on a wood project?

I usually schedule a day between projects, to refresh edges. Just normal maintainence....usually am doing any rehab work at the time, too.....while waiting on the next project to start.

IF I do stop during a project to refresh an edge...usually only 10 minutes, then back to work. YMMV:D

Especially with my knives, I have a tendency to get it really sharp and then cycle through them until I realize.... this thing is not sharp. And then I have a large stack to sharpen.

With my woodworking tools, I am more likely to do the fast touch-up while working. With my Shaptons, I rarely have to flatten. With my Arkansas stones, I even less rarely have to flatten (as in have not done it yet one one I purchased new.... or used).

No wait, what I really mean is that I never work wood. I just keep stropping looking for that perfect shaving edge!

[Eric Rathhaus]

I don't know how you have time to sharpen, Steven, with all the time you spend posting snarky comments on various forums.:D

[Jim Koepke]

I don't know how you have time to sharpen, Steven, with all the time you spend posting snarky comments on various forums.:D

LOL! :D

My sharpening tends to be done as needed. It only takes a few minutes to disassemble a plane, hone the blade, reassemble the plane and get back to work.

Maybe a little longer if a jug needs to be taken to the nearest faucet to use the water stones.

jtk

[steven c newman]

Tends to happen when one is chair-bound...hard to just sit around all day, unable to even get TO the shop.....tends to make one a tad bit...grumpy......

As for "snarky"? I return snarky for snarky....

Hmm, managed to get to the shop a bit ago....rehabbed 2 block planes....irons in both are OEM....and are sharpened back up to 600 grit...for now. Too sore to go out on a Quest for the Perfect Edge. One hour, counting "travel time" to the shop and back...was about all the old body could handle. BTW: Unicorn in effect.....Film if and when I can get back up out of this chair, waddle down the steps to the shop, and take a few pictures...may do a "Before & After" thing....

Sharpening Threads...never fails......

The Unicorn Machine...
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Old 6" Craftsman grinder...Brass wheel on the right, cloth wheel on the left...green stick to "charge" the cloth wheel up.

[Luke Dupont]

I usually sharpen as I need during work, but occasionally when I need stress relief, I'll go through my tools and knives and sharpen everything up.

I don't find it to be that big of a chore to pop the tool on a stone or two for a few minutes, but it can disrupt work when you have to sharpen a plane iron and then you also have to readjust the plane to take the right shaving again.

But, I confess to being one of those sharpening geeks who find some zen and relaxation in the process...

[Robert Hazelwood]

Re: Flattening an arkansas stone

I would not try to do it with a diamond plate. They are good for refreshing the surface of a flat stone if you want it to cut faster. But they are too slow for flattening a stone that is out to any significant degree. I would use coarse loose diamond or SiC grit on a flat surface, or 80 grit PSA sandpaper stuck down solidly to a flat surface and changing the paper often. If the stone is way out of flat, you can use the idler wheel of a belt sander to take off the high spots before lapping. I think David Weaver has a of video doing this.

I do not have a "Hard" Ark. But I do have a big Soft from Natural Whetstones and think it is great. I rub it a bit with a 320 grit diamond stone to keep it faster cutting and it seems to me like the perfect medium stone- cuts fast enough to establish good geometry but leaves a fine enough finish that the finishing stone can easily polish. I imagine most "hard" arks are more or less similar, especially if you abrade them regularly. If you let them settle in (don't abrade) then they should get a little finer than a Soft, and in that state may be a good finish stone.