Anyone Know what grade or grit Whetstone this is?

J

JamesV83

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Jul 6, 2009
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I've been looking online but I can't find one that's in a little black plastic slip like this one. It feels smooth as glass pretty much. It's a small pocket-sized stone. If anyone knows that'd be great. I've attached a few photos of the whetstone. Thanks for the help ya'll Happy NYE everyone!!
Indian-Mountain-Whetstone-by-James-Vally
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indian-mountain-whetstone-by-james-vally
 
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First, give it a thorough washing with dish detergent, because I think the smooth is coming from the fact that it looks loaded up with metal grit from previous sharpening sessions.

Come back when you've got that done.
 
Well....

I'm assuming you don't have any other sharpening tools to compare it to. Also, remember that free opinions are worth what you pay for them.

D'you have a stoneware coffee mug handy? Or, a stoneware dish should work too. If so, turn it upside down, gently of course.

On the bottom will be a ring where the cup meets the table, which is not finished. If you run your finger over it very carefully, you'll feel it's very slightly abrasive.

I'm going to guess that's about 1,000 grit, or about 8 Microns, but this kind of information is hard to find on the internet: there are a great many pieces about improvised sharpening, but none of them seem willing to put a number on the abrasive grade of the coffee mug/car window/concrete/etc. If you compare the feeling of the bottom of the mug to the feeling of the stone, you'll have a very broad idea of whether this stone is more is less than 1,000 grit.

Without having other stones or sharpening media on hand that you know what they are, it's going to be hard to tell what you've got in that slip case. My guess is a "hard" Arkansas or India stone, because I have one (Norton), myself. I don't know if they ever put an exact number on them because it's a natural material, with some variability built-in. I know that they're intended as the final step in the sharpening process, to get you that reflective, hair-shaving edge, and they're not much good if you haven't built up to that on coarser surfaces.
 
A simple Google search of "Indian Mountain Whetstones" shows that they indeed sell Arkansas stones...

That there then would in fact be a hard black Arkansas stone, used for finishing/polishing a final edge... Great for simple carbon steels and even old fashioned basic stainless varieties, but won't do much good against modern, high wear/abrasion resistant tool steels and powder steels...
 
JamesV83 said:
it's even more smooth than the bottom ring you were talking about Shorttime.
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Huh!

Well, it's possible that you have a 2,000 grit, or higher! A quick search shows me they go to 10,000, at least.

I don't think yours is that fine, though, those are like glass. I'm going to guess yours is somewhere from 2,000 to 4,000. But, that's just a guess.
 
Looks like a hard Arkansas stone. "Ultra Fine" is the rating. Used for final high polish/fine edge, after using a coarser stone, and for sharpening a straight razor.
As others have stated, good for the basic steels; 10xx, 420J2, 440A, and 420HC ... also T10, and the alphabet xCRxxMoV 420J2/440A/420HC equivalents, and whatever Victorinox, Mora, Boker, Opinel, MAM, and other European company's basic steels are. Not so much for D2, 440C and "above", where the carbides are harder than the stone.
 
It does look like a black hard Arkansas, sometimes called a 'surgical black' Arkansas stone. Those are pretty common in that small pocket-size format. The 'smooth as glass' description is apt as well, for that type of stone. More so, as they glaze with use (and this does happen pretty easily with these).

They are generally a polishing stone, used for simpler steels (plain carbon steel like 1095 or CV, low-alloy stainless like 420HC). Grit rating really doesn't apply, because it's a natural stone. Just know that in terms of performance, it'll be very slow in general. These can be useful as edge realignment stones or for burr cleanup on more wear-resistant steels, which otherwise wouldn't respond to a stone like this, for actual grinding purposes.
 
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I would not expect that stone to be much use on T-10 steel if it is anything like T-15. That is a high speed steel, predominantly alloyed with tungsten, but also containing vanadium and chromium. That means tungsten and vanadium carbides, which an Ark will not cut. I'm not familiar with T-10 so I can't say for sure it is what I think it is, but if so an Ark will be next to useless for any more than a very light touch-up. They produce a very nice edge indeed on plain carbon steels though.

And I would definitely agree that the pictured stone does look like a black Ark. The last picture makes it look like it is translucent also. You can check that by shining a bright flashlight into it near the edge in a dark room. If the light spills through it a bit near the edge it's a black or dark gray translucent. They don't transmit near as much light as the white stones, but are supposed to be among the finest.
 
JamesV83 said:
Will this put a polish on the edge of D2 or S30V/S35VN?
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It will burnish the daylights out of those steels and make a shiny smooth slick edge. So you would want to use a coarser stone to set the edge first before smoothing the bevel up.
 
JamesV83 said:
Will this put a polish on the edge of D2 or S30V/S35VN?
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Very slowly, to some degree. The caveat to this is, the glazing effect on the stone will happen much faster, meaning the carbides in those wear-resistant steels will tend to polish the stone more than the stone polishes the steel. The more glazed the stone becomes, the slower it'll work on any steel tried with it.
 
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appreciate all the great info guys thanks, I love this forum. What stones should I use for those steels then. Diamond stones, SiC, CBN? I also want to give my cutting edge a mirror shine
 
JamesV83 said:
appreciate all the great info guys thanks, I love this forum. What stones should I use for those steels then. Diamond stones, SiC, CBN? I also want to give my cutting edge a mirror shine
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For grinding & setting an edge on D2: AlOx, SiC or diamond all work. Due to the large chromium carbides in D2, I've preferred using diamond at the finishing stages, which handles them cleanly and leaves the edge crisper without eroding the support for the carbides at the apex. For polishing D2 especially, I've liked diamond compound (3 micron & finer) for that, used on wood. CBN compound should also work for that.

For S30V: Diamond all the way, for setting & refining edges. Some hones in CBN are becoming available too, and they should also work for that. Either diamond or cbn compounds for stropping it. And I'd likely take the same route with S35VN, though I haven't used that steel before. In both cases, this choice is due to the significant portion of vanadium carbides in these steels. At anything above 3%-4% vanadium in the steel, diamond/cbn makes a big difference at finishing stages, where lesser abrasives will struggle in refining the vanadium carbides at the apex.

Regarding the polishing aspects and considering the use of the hard black Arkansas for it, the 3-micron diamond/cbn compound on a firm or hard wood strop will do the job extremely well, and much faster than the black Ark will do it. And you won't have to worry about glazing the stone in the process.
 
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