Thread: Another whats under the stone post.

Originally Posted by StewieS

aaron; I am prepared to listen. Put forward your case that the stone is not an Ark, but a Washita.

StewieS.

I have no big reason. A while back I posted a stone real similar and it was identified to be a Washita by the people on this forum. Personally if you brought that stuff to me and asked me what it was I would say it's a Washita.
I still have yet to fully lap this Stone.

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Originally Posted by StewieS

~~~~ using the ANSI Standard, based it suggests the range of grit at 800 - 1000. I have some slight concerns with how the ANSI and JSI Standards vary greatly ~~~~~ I would rate this stone equivalent to 8000 grit.~~~~~

Yep that is how Ark's work, Dan's appears to be the cause of these inaccurate grit ratings, my opinion (not fact) Dan seem to rate his Ark's based on what the grit would be if you could remove a quartz crystal from the stone and measure it, which is just not reality on the hard ark's as they don't release slurry unless your doing something crazy like sharpening an axe with lots of pressure and gauging out bits of rock, I might also mention not all quarry's are the same.

Also burnishing of hard/translucent/hard black(SB) can bring them up into the 15k to 20k+ range on some stones when honing with light pressure such as a razor, it is more about how they work than any grit rating, so in effect I am saying my prior sentence about 15-20k is bad form as well, I would prefer to never even mention a grit rating on Ark's but people like numbers.
I would really like to just call them as Washita = medium, Translucent/SB = finisher and polisher etc.

my .3 cents.

That stone is loaded with oil, so how it looks can change. I have remove all the oil from all my Arks and use them with water and Smith’s water soluble Honing Solution. Removing all the oil can take some time, it took years of soaking in dirty swarf and oil to look like it does.

All that counts, is how it performs. If you have other Arks, compare it to them to see where it will fit in your progression.

You cannot grit rate natural stones, but you can compare them to known grit stones, and even that can change from one side to the other. A shiny bevel and especially one stropped, on Chrome Oxide, tells you nothing about the stone.

What the stone is called, or looks like, does not matter as much, as how it performs. If you are going to hone razors, on that stone, I would use one side for tool and a smooth prepped side for razors.

I doubt it is a finisher for razors. Blacks and Tranlucent’s, are much better finishers for razors.

Euclid; you may want to refer to work of the late Henk Bos, who applied a grit rating to the natural stones featured within his website. https://bosq.home.xs4all.nl/info%202...ing_part_3.pdf

StewieS.

Yup, familiar with their work.

They give estimates… of 2-3k spread.

You cannot grit rate a natural stone, they were made by nature, over hundreds of thousands of years, there was no quality control.

Another stone I recently purchased from the U.K. (Most likely the last honing stone I am going to purchase.)



The top surface of the stone showed no obvious signs to its origin.



But the underside was quite different, and the primary reason I chose to bid on this stone. The grain pattern indicated a natural stone, and not a man made stone.



Flat sanding with 220, followed by 400 grit w & d, highlighted it as being a quick release slurry stone, of a soft to medium hardness. The swirly grain pattern was now much more obvious to see after a light spray of water.



The next photo shows the sedimentary layering within the stones side grain.



Additional information;

Dimensions; 20.1 cm x 5.3 cm x 2.5 cm. (266 cm3)

Weight; 740 grams.

Specific Gravity (SF) = 2.78

Conclusion; the stone appears to be a highly featured Scotch Dalmore Blue. Possibly better suited to water as a lubricant than thin oil. A quick release slurry stone, suggesting a fast cutting stone. A high range in SF, indicating a large % of fine particles within its make up.

I would rate this as a high value/ high quality honing stone, purchased at a remarkably cheap price.

StewieS.

Originally Posted by Euclid440

Yup, familiar with their work.

They give estimates… of 2-3k spread.

You cannot grit rate a natural stone, they were made by nature, over hundreds of thousands of years, there was no quality control.

Euclid; not wanting to upset the apple cart between us, but a 2 -3 k judgement on the stones working properties, tells me far more about the stone than a simple rating of coarse, intermediate, or fine.

I understand that 2 natural stones of the same origin, mined from the same quarry, do need to be judged independently.

My apologies for reiterating my point of view. I will say no more on the subject.

regards StewieS.

Originally Posted by Euclid440

Yup, familiar with their work.

They give estimates… of 2-3k spread.

You cannot grit rate a natural stone, they were made by nature, over hundreds of thousands of years, there was no quality control.

Right on. I have tested plenty of natural stones and two examples of the same type stone can be considerably coarser or finer per example. I personally just like to rate natural stones as "razor bevel setter" "razor midrange" or "razor finisher." Alternatively swap the "razor" for knife, plane, chisel or whatever.

Dalmore Blue I would rate rate as "razor midrange" or "kitchen knife finisher."

That's a nice Dalmore Blue there Stewie. I like mine quite a lot for kitchen knives - quite a nice honing feel. I use mine with water. I would be kind of surprised if that was actually sold by Salmen. I'm inclined to think someone just stuck it in the sleeve.

I would be kind of surprised if that was actually sold by Salmen. I'm inclined to think someone just stuck it in the sleeve.

EKretz; I am assuming you have limited knowledge of Salmen's background as an owner, major dealer and exporter of U.K mined natural sharpening stones. They were equivalent to Pikes from the USA.

StewieS;

“My apologies for reiterating my point of view. I will say no more on the subject.”


Not a problem, your stone may perform at x grit performance, but some new guy reads your post and thinks he can buy the same stone and expect the same, a la Chinese “12” K or the ethereal rating of EBay Slates. It did sell a lot of rocks.

What you must remember is that others will read these posts and not knowing better, believe claims.

There is no quality control in nature. Take a walk through a stone yard and look at the difference in slabs, from one side to the other, 1inch of material.