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James Taglienti
06-04-2012, 10:23 PM
Is it pretty much agreed that the coarsest natural oilstone is washita? I have a tan colored one that is like 220 sandpaper, it is much coarser than any others i have seen. Has anyone seen any coarser ones? I use a medium india as my coarsest stone and i am looking for an intermediate. Might have to settle for a fine india, just curious about natural alternatives.

On a related note, is there a natural oilstone finer than hard transluscent? I have seen some jade and beryl on the internet anyone have any experiences?

David Weaver
06-04-2012, 10:40 PM
There are some slate hones that are super fine that take oil well (welsh slate, and finer than a dragon's tongue hone), as well as some super fine charnley forest. As variable as a translucent is, I don't know if there are many as fine as the fine welsh slate stones, if any.

I'd say that the norton translucent (the two that i've tried) were probably accurately similar to a 4k stone with some time to settle into that, freshly abraded they were probably more coarse. The dan's hone I had (HTA also) was probably twice as fine (who knows if they all are). And a purple and black pair of welsh slate hones that I have are in the ballpark of 1 1/2 times as fine as the dan's HTA. Different feel, too, a little more aggressive, but they can also settle in to being slow cutting if you wear the surface. Interesting stone with a slurry stone, though, something different than novaculite stones (though I wonder if an HTA would benefit from another novaculite piece as a slurry stone to wake it up a little without making it too coarse)

Anything vintage (like a charnley forest) that is well suited to razors is going to cost the moon. From what i've seen of those, they look to vary a good bit, too, with the fine ones being very very fine.

James Taglienti
06-04-2012, 11:20 PM
I have been using the same oil slurry on a washita for over a year, its jet black but it still cuts very fast. I guess im that "lazy carpenter" that the next generation of neanderthals will cuss when they are boiling my stones.
Played around the other day with a big thuringian stone, had a pasty slurry at one end fading down to just water at the other... went from a washita stone to a polish just on that one thruingian, pretty sweet! Made me wonder if i could duplicate it with oil...?

David Weaver
06-05-2012, 7:44 AM
I haven't used a thuringian yet. I've seen speculation that they go on slurry from a 6k stone to sky's the limit if you get a good branded escher. I haven't used a good one for the simple reason that a bench stone sized escher now brings $800, and I still don't believe any stone can't be improved by horse leather with chromium oxide powder (this is in regard to razors, of course).

Of course, if you find a thuringian in the wild and it's big enough to use, and it is fine, then that's good luck. The biggest escher's I've seen have come out of carpenter's traveling boxes, something we're often told the older craftspeople never fooled with - the "chasing the edge" syndrome the new woodworkers have. Someone on a razor forum a couple of months ago pulled a huge escher branded stone ...HUGE... out of a tool box at a flea market and paid $2 for it. It's probably a $1000-$1500 stone with the right razor buyer.

Anyway, on the oil stone, if you found a charnley forest that fine, or if you got a huge black welsh slate stone that fine, it wouldn't cut very fast on oil. If your thuri is fine like an escher, I don't think you'll be able to duplicate the speed and fineness with oil, but I haven't seen it all. There are gobs of older natural stones from europe that we don't get to play with.

Joel Moskowitz
06-05-2012, 10:01 AM
"were probably accurately similar to a 4k stone with some "

huh?
Modern Norton stones take a while to break in, they are cut with diamond saws and are initially very sharp but they wear in to unbelievable fine, slow cutting but
finer than all but the best of the 8K+ water stones and finer, but slower cutting than green stropping compound. All I can think of is that you are not giving the stone enough time to wear in or you are trying to flatten it mechanically, in which case the coarseness will return. German razor hones are also incredibly fine and cut faster than an arkansas stone but the reason that the Arkansas stones drove everything else off the market in the 19th century was because they were such a fine stone even at a considerable cost premium. Charney Forest stones are both coarser and softer.

Kevin Adams
06-05-2012, 2:02 PM
Joel, where does the Norton Lily White fall as compared to a soft ark? I know that's variable depending on the stone, but in general? My Lily White seems a bit finer than the soft ark, but perhaps works faster (which is nice).


Thanks.
Kevin

Tony Zaffuto
06-05-2012, 3:49 PM
Joel,

Is the Norton black arkansas stone finer, when broken in, than the Norton translucent? Why the price differential, if not finer?

David Weaver
06-05-2012, 4:17 PM
"were probably accurately similar to a 4k stone with some "

huh?
Modern Norton stones take a while to break in, they are cut with diamond saws and are initially very sharp but they wear in to unbelievable fine, slow cutting but
finer than all but the best of the 8K+ water stones and finer, but slower cutting than green stropping compound. All I can think of is that you are not giving the stone enough time to wear in or you are trying to flatten it mechanically, in which case the coarseness will return. German razor hones are also incredibly fine and cut faster than an arkansas stone but the reason that the Arkansas stones drove everything else off the market in the 19th century was because they were such a fine stone even at a considerable cost premium. Charney Forest stones are both coarser and softer.

That's not universally true for charnley forest. Some of them are coarse and softer, but some are extremely fine on oil. I suppose it is a trick getting a hold of a guaranteed fine one because a reputable seller will charge for the service of guaranteeing that.

When I got my norton stone (HTA), I used it until it didn't cut - several months without abrading it. The HTA that I got from Dan's (I got it for a song on clearance from some place) was definitely finer than the norton, probably by a factor of two. I'm sure they are variable, but the slip that I got from norton also was not as fine as I expected and about identical to the norton's bench stone. Looking at the composition I wondered if they were cut stones or if they were sintered or something from graded material. I guess not, they're cut?? That's the case for the stones I had in terms of fineness. When I eventually re-abraded the norton and abraded the dans, from the outset again, the dans was about twice as fine. That's just the way those two stones were.

I shaved off of most of my bench stones (anything synthetic 8k or above, and all of the naturals once they were allowed to settle in), and could definitely tell the difference between the different stones. The graded japanese razor hones were the finest I've used (of any natural stone, and they are too fine for tool use in practical terms), followed by the welsh slate (purple llyn melynllyn, and a finer black slate), and then the dan's translucent and then both of my nortons. The particle size in the norton trans must be fairly large, perhaps when they have just about stopped cutting they may equal an 8k waterstone, but they will not match an 8k waterstone in the hands of an experienced sharpener, one who will allow the surface of the stone to dry to complete the polish. And the base particles are much larger than an 8k waterstone, I would guess if I had to guess that they're in the 6 micron range.

I have never used an escher or equivalent antique fine thuringian, but until the are down in price by a factor of 10, I'll be unlikely to.

To be comparing to the chromium oxide i'm talking about, you must be using graded powder only or a guaranteed graded powder sized only slurry, which is significantly finer than the wax bars that say "microfine" on them and have some fairly large particles. In the words of Lynn on straight razor place (a professional Honer, I guess is the right term), he has never seen a stoned edge that wasn't improved by stropping with graded powder. Neither have I, despite being in possession of an antique hone that came out of a japanese barber's shop.

Also, to rely on an oilstone that has settled in to such a mode of polish only, you have to restrict yourself on what you use (in terms of steel composition), unless you are willing to charge the stone with something like 1/2 micron diamond or something (I wouldn't do that to a good oilstone, and it wouldn't make sense to spend the money on one, anyway, when cast iron makes a much better substrate). And you must use a sharpening method that is either coming off of a barely coarser stone, or lift the edge some to work only the finest amount. If there is a trans stone that is working directly off of norton medium india, then it hasn't settled in, and it's not that fine. I grew to appreciate the fineness of a stone that wasn't abraded, by lifting the edge, but there are many stones out there as fine as that and that cut much faster at that level (we are talking about a level of sharpness that offers an easy even full width1/2 thousandth shaving, whereas the next level up may provide something like .00025 or .0003 - impractical shaving thicknesses for woodworking, but still a differentiation in sharpness)

Shaving and stropping on bare leather is by far the easiest way to tell just how fine a stone actually is.

David Weaver
06-05-2012, 4:23 PM
What else was on the market in bench stones in the 19th century? I've seen an exhaustive list of turkey stones (the fine ones that are black and softer from the mediterranean, and not the brown washita stones over here labeled as turkey stones), charnleys, dragon's tongues, eschers, etc. as stones available to european woodworkers, and they also gave a favorable rating to oilstones, but I don't think a lot of the stones issued today are in the same ballpark as the stones bought by craftsmen who had more experience.

Also, the professional barbering literature that is on straight razor place around the turn of the century suggests thuringians/eschers and "peculiar far east" stones from japan (or something along those lines) and suggested avoiding all others.

And to reiterate, there is no stone that I'm aware of that matches 1/2 micron graded chromium oxide powder. Not in the shave, and not under the microscope (under the same microscope, there are fairly large scratches left from the green "microfine" crayon, from aluminum oxide in the mix).

Joel Moskowitz
06-05-2012, 5:12 PM
Obviously your results differ from mine and just about anyone I know. Walter Rose mentions that as soon as the workman could get Washita stones they quickly ditched their charney forest stones. It is possible of course that differences in steel and steel hardness makes the stones perform differently. I can only answer for woodworking tools. This AM I sharpened up a mess of carving tools - worked great.

My sense about the nortons vs dans is that the norton stone is harder and what you take as "stop cutting" is when I say great we are in business. I have never seen an arkansas stone that stopped cutting unless it was clogged - but that's hard to do with a good fine arkansas stone. But I guess there is always a first time.

David Weaver
06-05-2012, 5:34 PM
When I say stopped cutting, i'm also saying that's where the stone has settled into a state when it can be used well. It has not truly stopped cutting, it would be worthless then. But it does not raise much black slurry at that point and as warren mickley points out, it is a subjective point when the stone is used to polish an edge, and not to cut one.

One where you can remove the wire edge if one exists in a significant manner by a quick palm stropping.

I doubt the charnley forests that have been selected as razor stones are the same as the type you're referring to. They are likely harder and finer. Both stones are novaculite stones, all natural stones are variable to some extent.

Perhaps you were dealing with charnley stones that were selected for woodworkers. If you look on ebay at the charnley stones that are targeted toward razor sharpeners, you're likely to find stones finer than any HTA that you've ever used.

David Weaver
06-05-2012, 5:56 PM
Jim - i forgot one other very fine hone - the guangxi stone that woodcraft sells. it is a slow stone, though, on clear water. it might be unusable on oil. it does well slurried, though, esp if you slurry it with another same type stone. i haven't found the same thing sold on ebay to be as good of quality as the ones woodcraft has.

Joel Moskowitz
06-05-2012, 6:39 PM
Are we talking about the same charney forest? Charney forest stones as sold in the 19th century were soft, abrasive in a clay/slate substrate. I can scratch or dig into mine pretty easily. They had to be soft because the way they were finished cut and flattened was all by hand. Of course the abrasive is quartz but I would not call it a novaculite by a long shot.

David Weaver
06-05-2012, 7:14 PM
There must be a difference between stones. I don't want to start an argument about charnley forest stones, i guess, because it seems like there's a far different context of the charnley forest hones you're talking about and the ones that are still popular (though not common) due to suitability for razor use.

I don't think we're talking about the same things in general. I have heard people state that their charnley's are similar to a dragon's tongue (which is about where a 6-8k stone is) and I've also heard charnley's that folks describe as working a razor at about a 20k grit level. Those comments are subjective, but they are made in context with synthetic stones.

So my llyn melynllyn is classified as a 12-15k grit stone, and I'd say that's about accurate if it's allowed to settle (I don't think it's that fine on slurry).

And a charnley will often be given a grit estimate by a seller - see ebay item
180895375074

(no relation to the seller, of course, though I did buy two stones from him and will give him the benefit of the doubt on his grit estimates)

I couldn't find one that I thought might be more representative of a tooling stone.

Here is another razor stone:

http://www.youtube.com/watch?v=lf9UY_Hs9SE


You can get an idea of how fast this stone is working by how little black there is from the razor - it is a fine stone.

Could it be that different quarries/layers had different density and fineness?

David Weaver
06-05-2012, 7:19 PM
For comparison about the speed of that charnley's cutting, here is a coticule (presumably you've gotten a hold of a coticule at some point, good ones also cost the moon now).
http://www.youtube.com/watch?v=Z8ZVeYNPwwE&feature=relmfu

They're well regarded for razor sharpening, and they vary a lot, but I would categorize them as a stone that makes an edge that is only moderately keen, but somehow is soft to shave with and doesn't rip your face up like other stones with similar grit level (I got a little razorburn straight off of a settled in translucent arkansas, and a lot off of a slate hone that was probably about 8k in grit).

Joel Moskowitz
06-05-2012, 7:30 PM
I have a few Coticules new, old, never really cottened to them. For woodworking tools I mostly use waterstones, for carving tools arkansas stones. the latter because of the lack of need for maintenance.

Chris Griggs
06-05-2012, 8:18 PM
Can't you "wear in" (give a finer surface to) a hard Arkansas (black or HTA) by dressing the surface with very fine sandpaper?

David Weaver
06-05-2012, 8:30 PM
You can get it a good part of the way doing that. Same thing as rubbing it with another hard stone. If you had two black arks that you could mash together, you could get them close to where you want them.

Most of the razor fans will either avoid coarse lapping, or follow the coarse lapping with progressively finer stuff until they have a surface they can live with. For the natural stones, I would agree with joel that it's nice to not abrade the surface on the fine ones. Stuff like a hard ark, my opinion is that it's nice to abrade one side and not the other. Then you get the benefits of having a coarser stone and a finer stone in one.

Joel Moskowitz
06-05-2012, 8:38 PM
The short answer is no.
The long answer has two parts. in the old days arkansas stones were cut by abrasion. A steel wire, mixed with abrasive was drawn through the material. This cut slow but smooth. The crystals of the final surfaces were rounded and smooth from all that loose abrasive bouncing around an getting finer and finer.
Modern stones are made with diamond saws. THe stones are left with sharp crystals that cut coarsely.
Finishing of slips, odd shaped stones, and some makers is still don't with abrasives.

If you take a new stone and use it for awhile it will slowly mellow and and you get a super fine slow cutting stone. Slow cutting because unlike a sharp abrasive, rounded, dull crystals cut slower.

Now if you want to speed up the process and use a fine abrasive all you are doing is cutting fine grooves in your stone. The stone is hard and unlike a friable waterstone being flattened the grooves will form a rougher cutting edge that in itself has to be worn down and wil not easily be removed.. The harder the stone (and Norton's stones are very hard) the longer this process will take. (think of how the grading stone works on a tormak - same idea but the consequence here is undesired.)
On our shop arkansas stone (11 1/2" long) - it probably took a year of so of use. The ends of the stone are still comparatively rough but the middle of the stone we actually use fairly regularly is like glass and cuts a treat.

Chris Griggs
06-05-2012, 9:06 PM
Thanks for the detailed explanations Joel and Dave.

Joel, your house stone sounds like my Halls black. I've used it intermittently for about a year and with exception of the ends its quite glassy - I've read that the halls blacks are very fine which is part of why I chose it, but honestly don't know how it compares to other hard arks, blacks or HTAs. I'd put it at about a 4k in terms of edge, but its probably not fully worn in. Its annoying that the Halls and many other Arks (don't know how the Nortons are) don't come very flat. I still need to go back and work mine flatter which, of course, will make it rough cutting again not mention be a royal PITA to do. I have one side that I've scuffed up a number of times and when its freshly scuffed it cuts pretty similarly to my soft ark when its freshly scuffed. Oh well, I'll get around to it one of these days. I hardly use my arks anyway.

Its weird, I love black and trans arks, they're so smooth and hard and so convenient just to leave sitting on the bench. But at the end of the day I always go back to my waterstones (and Joel, I have finally come around to loving Choseras BTW) since I consistently get a better edge and get it much faster. I think I'll probably end up using my Arks for carving tools like you do, if I ever get into carving, and I also like them for scrapers. The metal is soft so they cut it quite fast and it avoids wearing grooves in my expensive waterstones.

So Joel, how are those Norton Blacks you just got in? Are something extra special or pretty much the the same as the HTAs, just in different clothing?

David Weaver
06-05-2012, 9:21 PM
The groove issue shouldn't be a problem if you condition the surface with like stones or go up to about 2k grit wet and dry (which is what a lot of razor folks do).

I prefer the like stone issue, but it doesn't do a lot of good if the stone is way out. With like stones (with old very hard japanese stones) I don't lose the great fineness of the stones.

That might not be that productive with a black ark, I don't know. I had a halls black like you're talking about and it was also very far out of flat. I don't know why it was so far out, but mine was a 12x3 stone that I found fairly cheap ($90 shipped) for a stone that size. It was so far out of flat that I never did get the whole thing in plane, and got tired of it cutting coarse and once I had an area about 8x 2 1/2, i just used it from then on.

Chris Griggs
06-05-2012, 9:30 PM
Well mine's only 8x2 so I'll probably get it flat eventually, but given that I have other medium it feels like a colossal waste of time. It just a matter of me bothering. Like yours the center is flat (ish) in about a 7 x 1.5 area, but the edge are out of flat and when it was new it was worse. Its a shame because its a nice stone otherwise and I like Halls as business otherwise (knowledgeable and good service), but I were to do it again I'd find a place that would sell me a flatter stone.

Wasn't this thread supposed to be about coarse stones...:)

Joel Moskowitz
06-05-2012, 10:19 PM
Chris,
Up until recently Norton never separated out their black arkansas stones. When you bought an HB8 you got a stone that could be white, black, red, brown. I have one stone that is just to pretty to use - it's a rainbow sawed in the middle of a geode like thing. They did sell black arkansas to some specialized industries but you won't see that distinction in their catalogs (ever as far as I know).

They do sell HM8 which are stones which one side has a defect.

The reason is that stones are graded in the industry by density not color. The higher the density the harder and finer the stone. Color interpretations vary from quarry to quarry.
So is the black ark that Norton sells extra special? I don't know. I know some people prefer it, but I haven't tried it. I have my own personal stone that is nicely worn in, my shop stones, and frankly I can't justify switching for a test. They do feel smoother out of the box, so my quess is that the break in period might be shorter but I don't know if they are actually finer. I can't imagine it anyway but it might be.

If your stone is a little convex it was finished by hand and should work fine for woodworking - just use it eventually in 20 or 30 years it might wear flat. certainly for carving tools it makes little difference but for doing a back of a flat chisel maybe.

Of your new stone in concave - send it back.

Joel Moskowitz
06-05-2012, 10:20 PM
Chris,
Up until recently Norton never separated out their black arkansas stones. When you bought an HB8 you got a stone that could be white, black, red, brown. I have one stone that is just to pretty to use - it's a rainbow sawed in the middle of a geode like thing. They did sell black arkansas to some specialized industries but you won't see that distinction in their catalogs (ever as far as I know).

They do sell HM8 which are stones which one side has a defect.

The reason is that stones are graded in the industry by density not color. The higher the density the harder and finer the stone. Color interpretations vary from quarry to quarry.
So is the black ark that Norton sells extra special? I don't know. I know some people prefer it, but I haven't tried it. I have my own personal stone that is nicely worn in, my shop stones, and frankly I can't justify switching for a test. They do feel smoother out of the box, so my quess is that the break in period might be shorter but I don't know if they are actually finer. I can't imagine it anyway but it might be.

If your stone is a little convex it was finished by hand and should work fine for woodworking - just use it eventually in 20 or 30 years it might wear flat. certainly for carving tools it makes little difference but for doing a back of a flat chisel maybe.

if your new stone is concave - send it back.

Chris Griggs
06-06-2012, 7:26 AM
Thanks for the info Joel. I'm just always curious to hear opinions on different hard Arks. Some folks swear up and down that blacks and trans are quite different and others say they are pretty much the same. Probably depends on the individual quarry. My understanding though has always been what you just said, that its the density that determines the stone, not the color, and that differences in price have more to do with availability/rarity then than anything else. I didn't realize that Norton didn't previously separate out their stones at, that's interesting. That all clarifies for me the stones that Dan's sells that they call "True-hards" they describe them as the same fineness and density as their blacks and trans, but w/o the color standards.

Anyway, out-of-flatness is/was what you describe - convex from hand lapping. It is only a concern on chisel backs. I'm probably worrying too much about it, but that said I don't want to risk throwing my nice flat chisel backs out of flat whack so I avoid sharpening chisels on them. Thanks again for the info.

george wilson
06-06-2012, 8:38 AM
I have a nice,never used coticule that has the original decal on it. I have never used it because I don't want to ruin the decal!! It is a rectangular stone,about 3" x 4",about 1" thick. cream on one side,and blue/purple on the other. I wonder what it's worth?

David Weaver
06-06-2012, 9:21 AM
$100-$150 for the razor sharpeners if it is suitable for razors.

The big coticules are expensive, and I see a lot of criticism about the fineness of some of the new ones. But that's universal, it's not like there aren't old ones that are coarser than others, and someone has to just about be an expert of the big ones to know what the different names mean and what the likelihood of getting what you want is.

The new ones where someone just sells an "8x3 coticule" without saying what it is, kind of nutty I think. Especially when they want about $350 for them.

george wilson
06-06-2012, 8:02 PM
My stone is old,but I don't know HOW old. I picked it up in the 70's,and haven't wanted to wear off the nice decal. It looked old but not used when I got it.Now,I need to find where I put it.

Joel Moskowitz
06-06-2012, 8:55 PM
My stone is old,but I don't know HOW old. I picked it up in the 70's,and haven't wanted to wear off the nice decal. It looked old but not used when I got it.Now,I need to find where I put it.

Based on when coticule stones were made I would say the stone is old, at least several million years. The decal on the other hand is probably a lot newer.

george wilson
06-06-2012, 10:08 PM
A wise observation,Joel!!

Chris Vandiver
06-07-2012, 1:24 PM
Based on when coticule stones were made I would say the stone is old, at least several million years. The decal on the other hand is probably a lot newer.

I think you meant to say, several hundred million years old.