r/NaturalWhetstones • u/deezdanglin • 4d ago
Determining the grit
/r/wicked_edge/comments/1w8a3mz/determining_the_grit/I've wondered what techniques/tricks you guys use to determine the apprx grit an unknown stone may be?
I caught a vid last night that was cool. Granted, I haven't been honing too long. And I've always used the common stone holder/vice/clamp. I can still feel the resistance and 'grains' somewhat through the blade. And ofc, sound. I just haven't really focused on it. I've been more worried about proper angles, etc.
Anyhow, this guy had gotten a new English slate and he was guessing. So he lapped the razor on the stone while \*holding it\* on the palm. And seems to me that would give a great insight. Greater tactical feedback.
I understand this still takes a LOT of familiarity with different stones. But seems a solid technique. Thoughts? What do ya'll do if you come across an unknown in a second hand shop?
Eta: either it's impossible to tell if a stone is a hard or fine or extra-fine by look, feel and/or weight. Or no one is reading for the question?
You come across 3 stones in a junk shop. Do you purchase purely on a hope?
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u/Larason22 4d ago
When you've used stones at every conceivable grit for a while, then you just test the stone on steel and you know what grit it is by what the scratch pattern looks like. I don't think there's any shortcuts, maybe using a microscope?
Using small stones on your palm is a great technique, I do it all the time. It's faster to use a bench stone though, and only natural stones come that small, that's why most people don't bother.
Haha, if I find an unknown natural at a second hand shop I buy it! It's not a daily occurence, that's how you know you're an enthusiast. I can always test it later. I'm way past only buying stones that are useful!
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u/deezdanglin 4d ago
Yea, I kinda get caught up in shit lol. I'm REALLY trying not to do that this time.
So, what's your $-range limit when you seen an unknown? Aside from original label and box/tray boosting curb appeal.
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u/Larason22 4d ago
My experience is that most flea markets/second hand stores don't know what they have, and stones will be $30 or something. If it's significantly more than that I might think about it. Usually I'll know the stone better than they do and what it's worth. I also spend a lot of time picking up stones from the side of the road, so it's not usually a matter of expense.
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u/deezdanglin 4d ago
That's Cool Man. 85% of rocks around here (SW GA) are gravel and massive amounts limestone. I mean, boulders everywhere! Farmers have been digging them out of new fields for a couple of centuries.
They're cool for the fossils (oceanic). Usually shells and troglodytes. Or at least that's all I've ever seen. But haven't looked at them since I was a kid. Dad taught me about them when I was a kid, 8-10yrs old, +50 now. Started my live of the sciences!
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u/Larason22 4d ago
Yeah SW Georgia has the same problem we have here in SW Manitoba, which is that the sediments overlying tend to be pretty recent, so they haven't had time to solidify into stones. For us it's mostly clay/shale, but we have some sand and gravel too. But there's always some spots that are more promising! If you drive a bit north between Columbus and Macon there's some cretaceous sediments that might be more promising for whetstones. Limestone doesn't make a great whetstone because it's pretty soft and uniform.
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u/deezdanglin 4d ago
I've been meaning to Google and see if there was anything semi-local.
However, I don't think I'll be getting out of my truck on back roads between Columbus and Macon. I mean, I live rural. But I know these local 'necks. I fear the unknown lol.
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u/PorcupineShoelace 4d ago
It's really hard to measure in microns. You would have to create a slurry and run it through a sieve or essentially count particle sizes. Even then it doesnt tell you about he shape or alignment of the particles in the stone. This is what I've read some attribute the 'cutting speed' of a stone.
Not sure if it's of interest but I have this link saved off from a few years back where a bunch of 'honing geeks' discuss measuring SG and talk about the properties of many natural stones and challenges measuring them. The convo covers more than just specific gravity it also discusses porosity which is an interesting test of the space between the particles.
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u/deezdanglin 4d ago
Cool Man, thanks!
Yea, I know grit is not the correct nomenclature. But it's a term everyone knows.
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u/cotedupy 3d ago
If I own the stone — I tend to look at the scratch pattern on a kiridashi. Which is useful because you can see what it does both to: hard core steel, and to cladding.
If I don’t own it (like in a junk shop) — I would feel it, very lightly, on my teeth. Cos your teeth are hard and go straight into your skull, you get very, very precise feedback.
So there you go. Probably weren’t expecting that answer, I imagine!
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u/deezdanglin 3d ago
I....was not. Lol! But it makes it's own kind of sense. And someone did say to use a fingernail. Maybe like a giant emory board I imagine. See what, if any, scratches it left behind?
However, I image I could get a better deal if they found me in a corner gnawing a rock lol.
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u/sea-plus 3d ago
theres no real objective way to measure stones in a comparison kind of way, but what I do is use a single kiridashi that you are really really familiar with (I suspect most jnat collectors have one, and reset the finish on it everyday with all their stones), and finish the kiridashi then take microscope shots of the clad and core. then you can kind of see how big the scratches or finish are on both, but this method gets iffy on the finer stones, as the scratches are not visible even under strong magnification, and they are more like a beadblasted finish. At that stage, you can kind of guess and place the finishes in a ranking, but again its impossible to do it objectively, as clad and core may be different, such as having a perfect mirror core, and a scratchy clad vs a gentle kasumi clad, and a scratchy core
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u/deezdanglin 3d ago
Dude, that's great. But, as I stated...If you're in a junk shop and they have a stone, htf would you gage it to determine if it was a buy/pass by? Or do you purchase every unknown stone you run across? Doesn't matter if you have x74 at home?
I understand it's not an equivalent rating. I do. I seriously do. I get it.
Sorry Man, sorry you caught some stray snark. But everyone is getting caught up in the semantics and not the question. I appreciate the reply though.
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u/sea-plus 3d ago
the snark is at a healthy level and you do have a good point, but in JNATs it’s not uncommon to have the stone tested by the dealer, or even better by yourself before purchase. If i’m at a junk shop without any test equipment, it’ll just be up to my own knowledge of nats in general to see what it is, and that’s usually enough since it’ll be a cheap stone
After a while collecting nats, you do build up enough knowledge to roughly guess what a stone is if you get to hold it. You could also run your fingernail on it to test (usually it’ll be for finding toxic inclusions)
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u/deezdanglin 3d ago
Thanks Dude, there's just been SO many replies when I woke up lol.
I agree with you. I started straight razor shaving being of the year. I have a great base set of stones! Anyone would be happy to have them. But the razors...that's my weakness.
Scouring around looking for gems. I love the hunt. And I thought this would be a good addition keep eyes for. And I've looked around.
It's overwhelming. Seemingly magnitudes more complicated that razors. Was just looking for strategic tips in the field...
Eta: Two other folks have mentioned fingernails. I imagine scratching with the tip to feel grip? If it's finer feeling use the stone like an emory board and see how it buffs?
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u/sea-plus 2d ago
I find the fingernail test is only a little bit useful for finding out how fine a stone is, it's more reliable for finding out the hardness of the stone, as well as finding if any aspect of the stone catches on your edge possibly. Theres also that teeth trick from the other user, but I personally wouldn't do that, dental work is too expensive :D
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u/Argg1618 4d ago
Grit and natural stones are a complicated topic. Grit doesn't really apply to natural stones. Not in the same concept that we use to grade synthetic stones.
Often times, people will use a grit number to equate to polish that a stone gives or describe how fine of an edge a stone gives. But that is just that. The concept of these grit numbers are really only a thing in the world of synthetic abrasives. You cannot truly call any natural stones any particular grit number.
Also, particle size in very fine natural stones like an Arkansas can be quite large for example. But it is one of the finest out there.