Flattening a hard stone

[Lasse Hilbrandt]

When searching for ways to flatten a hard arkansas most people recommend using loose grit on a plate of float glas.
But will the loose grit not just grind the Glas out of flat just as fast as it flattens the stone?

[Rafael Herrera]

I had good results flattening several Washita stones using SIC powder and float glass.

[Kevin Jenness]

If you have access to a 3 year old child, tie the stone to a tricycle and let them drag it around on a concrete floor.

[Warren Mickley]

Do you really have a hard Arkansas stone that is dished? Mine is 46 years old and has not lost a thousandth of an inch anywhere. I think I flattened my soft Arkansas stone about thirty years ago, but I am not sure. My Washita stone I have flattened a few times but now I use one side for plane irons and one for gouges, which is not as critical.

[Oskar Sedell]

I flattened my washita (which was dished maybe 1 mm over its length) on a piece of flat construction iron/steel. Flat enough but I did not worry too much about micrometer flatness.

Same principle as in using a sharpening stone - dont grind all the time in one place. I worked the SiC powder around over the full surface, and swapped ends of the washita from time to time.

When I was done I took the washita to a diamond plate just to confirm flatness (took just a few minutes, the arkansas stone got very flat with SiC powder only).

Probably the iron plate got a little dished in the process, but nothing that in any way rendered it useless.

[Andrew Pitonyak]

A few things to consider:

What grit should you use? The finer the surface, the finer the surface on your stone. My guess is that on a "fine" stone, you want 220 grit and a course stone closer to 120 grit. Really fine? How about 600 then 1200 grit?

One guy flattened his stone using sandpaper. it worked, but he ended up with a very glassy smooth surface. This is probably because the carbides fractured and became smaller so he also had to recondition the stone to put back a rougher surface.

I read a recommendation to buy a cheap silicone carbide or Aluminum Oxide stone and then put loose grit on that stone. Just search "home depot tile rubbing stone" and you will fine a stone for about $10.

I have heard stories about people ruining their Diamond stones, but I have already read about people being happy doing it this way. I would probably try a cheap diamond stone from say Harbor freight,i think that they sell one.

You might also try.... the back of a floor tile or even a sidewalk surface.

Can you get a course diamond paste?

I did see a recommendation that you "boil" your oil stone first to get oil and gunk out of it.

Oh, if you want to purchase some grit:
https://gotgrit.com/index.php/cPath/2_6/sort/2a/page/1/osCsid/e0995b368395a9917900523fd50c4d09

[ken hatch]

I'm with Warren,

A Hard Black or Surgical Ark shouldn't need flatting. First question how do you know it needs flatting, if by chance it does, then a 600 grit Atoma diamond plate works about well as anything.

ken

[Andrew Pitonyak]

I'm with Warren,

A Hard Black or Surgical Ark shouldn't need flatting. First question how do you know it needs flatting, if by chance it does, then a 600 grit Atoma diamond plate works about well as anything.

ken

Depends on the "hard" stone. I have a "hard" stone. Best orders their stones soft, hard, black surgical, translucent. Preyda is soft, hard, hard black, translucent, surgical black. Dan's is soft, hard, translucent, Black.

Given that these are placing hard one step above soft, it might dish. I have never seen it, but maybe.

What I am more likely to expect is that it needs to be "resurfaced" or "reconditioned".

So, is the stone actually dished?

[Lasse Hilbrandt]

It's a genuine Washita, which is slightly dished, perhaps 1mm.
The reason the question was regarding a hard (I meant hard, like a translucent) was that I'm on the lookout for one, but most I see advertised on ebay as "hard" is dished enough to see it on the pictures.

[Steve Voigt]

When searching for ways to flatten a hard arkansas most people recommend using loose grit on a plate of float glas.
But will the loose grit not just grind the Glas out of flat just as fast as it flattens the stone?

No, it will not. Glass is softer than novaculite, so the particles embed partially in the glass and abrade the stone.
If you want to save your glass, you can buy plastic laminate sheets from Lee Valley. I used to use these to flatten all my stones, and still do when I flatten India stones. For novaculite, I now use an Atoma, just because it's faster and more convenient.

[ken hatch]

Lasse,

You will pay more for a Translucent stone than for a Hard Black/Surgical Black and It may not polish as well. These are natural stones and there can be great variation between stones of the same "grade". Which could mean you will have to kiss a few frogs before finding your soul mate. Once you do it will be worth the hunt. I've found Dan's stones are pretty consistent with his grading. Good luck with the hunt.

ken

[Andrew Pitonyak]

Lasse,

You will pay more for a Translucent stone than for a Hard Black/Surgical Black and It may not polish as well. These are natural stones and there can be great variation between stones of the same "grade". Which could mean you will have to kiss a few frogs before finding your soul mate. Once you do it will be worth the hunt. I've found Dan's stones are pretty consistent with his grading. Good luck with the hunt.

ken

I have found "Dan's Black Arkansas" to be their finest stone and they claim it is finer than their Translucent (and less expensive).

If you go with Best Sharpening Stones, they claim that the Translucent is their finest stone. I am not convinced that their Translucent is finer than Dan's Black Arkansas; yes, I own sets of both.

[Jim Koepke]

My Dan's Translucent slip stone is not as smooth as my Dan's black bench stone.

My unknown source greyish translucent seems to be every bit as smooth as my Dan's black. My unknown stone is only smooth on three sides. The rest of it is rough, nowhere near flat stone.

My Dan's soft Arkansas stone is pretty close to my Dan's hard Arkansas stone.

My other four oilstones are all of Washita type or about the same hardness. To varying degrees they all show evidence of being dished.

One is when you run a flat edge over the stone and there is a shallow collection of oil in the center where the blade just passed.

jtk

[ken hatch]

I have found "Dan's Black Arkansas" to be their finest stone and they claim it is finer than their Translucent (and less expensive).

If you go with Best Sharpening Stones, they claim that the Translucent is their finest stone. I am not convinced that their Translucent is finer than Dan's Black Arkansas; yes, I own sets of both.


Andrew,

I have a number of Dan's stones in my sharpening cabinet, from soft to Black (several) including a Translucent. Of my "polishing" stones the Translucent falls in the middle better than a couple of the Hard Black stones but will not touch my favorite Hard Black in either "feel" or quality of the edge before stropping. That said, stropping is the great leveler. With a strop any of the Black or Translucent stones give a good edge.

My current four stone rotation when trying for the best edge is a Medium India for grinding, a two step honing using first a Pike "Lilly White" Washita to clean up after the India first followed by a Norton Hard White to prep for polishing, and polishing on my "special" Dan's Hard Black followed buy a couple or three pulls on a oiled Horse Butt strop to rid the edge of anything left that looks back at me. Any one of the stones can be dropped out of the rotation and still get a good "working edge".

ken

[Andrew Pitonyak]

Andrew,

I have a number of Dan's stones in my sharpening cabinet, from soft to Black (several) including a Translucent. Of my "polishing" stones the Translucent falls in the middle better than a couple of the Hard Black stones but will not touch my favorite Hard Black in either "feel" or quality of the edge before stropping. That said, stropping is the great leveler. With a strop any of the Black or Translucent stones give a good edge.

My current four stone rotation when trying for the best edge is a Medium India for grinding, a two step honing using first a Pike "Lilly White" Washita to clean up after the India first followed by a Norton Hard White to prep for polishing, and polishing on my "special" Dan's Hard Black followed buy a couple or three pulls on a oiled Horse Butt strop to rid the edge of anything left that looks back at me. Any one of the stones can be dropped out of the rotation and still get a good "working edge".

ken

I have a couple (four or five I think) of the Dan's Hard Black and only two of their Translucent (I think only two, maybe three, I would need to check).

I do need to up my "stropping" game. I feel like I keep improving my sharpening while I also feel like there is so much that I do not know. Using a strop is probably my weakest skill. Steve (about 45 minutes away) is very good with a strop, I need to bribe him with Mexican food for stropping lessons; not that I can go see him for a while given the state of things, but covid-19 issues will pass. Part of the issue is that I have trouble seeing a difference if I come off the Shapton 16000, but, I think that it makes much more of a difference coming off a Washita. I purchased some washitas to try, I just have not had time to do it. Probably will not until I get the "blessing box" that I made for the church out of the basement. It is large and taking up significant room in the shop.

I have only flattened Arkansas stones using a diamond plate. These were very small stones (like 1/2" x 3") as part of a set attached to steel rods. Very old. I was very cautious because i was afraid that I would destroy the diamond plate. Now I have SIC grit and some float glass, but I have not tired it on anything yet. I expect to since I have some odd stones to flatten.