Thread: What is the Sp Gr of Your Best Arkansas Stone

Originally Posted by DaveW

Definitely no reason to check SG on a hone that you're happy with. The standards are probably there centuries old because the original sellers would sell soft stones as hard to get a higher price, etc, same as folks would shave silver off of quarters.

Raises another question that I'm curious about. Softer versus harder in a finisher. I've come across a few Escher yellow/greens that, in addition to the y/g end label, had a label on the opposite end printed "guaranteed soft." Obviously a selling point if they went to the trouble of printing a label to advertise the fact. It seems that the y/g was faster than the other colors without sacrificing fineness. No question that hard novaculite stones have the rep of being slow while fine. I guess in a novaculite softer would correspond to coarser ?

All of the novaculite stones refuse to release particles in regular use, other than the odd particle here or there. The pike washitas at some point had stickers on the end that said "hard and fine" or "soft" and they may have said fast or something on the soft. In washita type stones (still novaculite, but a little different in structure vs. cheap soft stones), the smaller pore stones are definitely finer cutting and can finish a razor once settled in. Maybe the soft ones can, too, but I don't know that I have any cutting that slowly.

On eschers, there must be something in translation about how the barbers used the soft ones. I wonder if soft means self slurrying (which results in an edge that's not very fine if the edge is worked to) or if it just means a better feel. I had a y/g and it took a while to settle in. Anything that would've described it as soft (as a sticker on the end) was long gone. Compared to jnats and such, though, I was surprised how long it took for the escher to stop slurrying, and since I was sharpening the entire bevel all the way to the edge, it was immediately clear that while the stone was still slurrying, the edge wasn't what I'd want.

If Id have, however, worked to the edge, put the razor on the linen and strop, and then given a few more light strokes (which seems to be a decent recipe for a marginal stone), it probably would've been better.

long story short, softer is coarser, but softer really means less density and more space between abrasive clusters and the clusters themselves with the sharp edges from the space can do cutting. If the stone is more dense with less air space and relief for the particles and matrix to cut, then it cuts more finely.

One of the reasons, I think, that the pike washitas were so well loved by carpenters is because they are porous and those pores cut and never quite stop cutting. Cutting speed obviously being more important to a carpenter or cabinetmaker than to a single individual shaving with a razor.

I'd like to have a conversation with a high end barber in the late 1800s to see how they're using their stones and what they like. When I see a self slurrying stone, I always assume that anyone using it wants a fast cutter and isn't going to use it all the way to the edge of the razor for fear of making the edge more coarse.

Originally Posted by JimmyHAD

I had never heard of specific gravity before this thread. I'd like to know the sg of my arks, coticules but I'm not going to go through the learning curve to do the requisite test. I don't want to know that badly. If it turned out that the test reflected I had a 'good' stone, I'd be a happy camper. Then again, it could turn out is was otherwise, according to the sg. I'm satisfied with the 'rubber meets the road' test. Honing razors/knives on the darn things. Not knocking the concept of the finding the sg of your stones. I think it is a cool idea, if I knew how to do it, and if it was easy, I probably would.

I don't know if sp gr is relavant in all natural stones, certainly not for comparing different types of stones but Arkansas are graded by sp gr rather than grit size. Anything over 2.5 qualifies as a True Hard which included black and translucent. The grading standard does not distiguish between a 2.5 and a 2.8 stone even though one may produce a finer edge than the other, they are both True Hard. It would be nice if the stones above 2.5 had the sp gr marked on them so you could tell what you were buying.

If you have access to a decent scale you can get a graduated cylinder for a few bucks off ebay. That is all you need to do the measurement.

If you have a set of dial calipers and an accurate postal scale that does mg, you can get the volume of a regularly shaped stone pretty easily. I don't suppose most people have a dial caliper, though, but anyone here who reloads probably does. The width and the thickness are the most critical manual measurements, and the thickness is probably really the only measurement that requires the use of a caliper or a very finely graded metric rule.

You're right that the standard doesn't distinguish between 2.5 and 2.8, and now what appears to be 2.4 from the us govt instead of 2.5. in my experience, the stones at 2.6 are marginal translucents, and the stone that I have at 2.5 has zero chance of any light transmission. If someone gets a 2.5 SG stone, they will probably feel that it's not really a finisher, and 2.4, they will definitely feel like they were had. I haven't seen a black stone below 2.6, and the black stone I had from norton at 2.6 still also seemed a bit coarse. I've only had one norton black stone, though, but three translucents (and all of the translucents were about the same).

I thought I might find that some of my vintage stones were really really dense, but the couple that I have are in the 2.65-2.7 range, IIRC. Nothing has been more dense than the black trans at NW, and that's not necessarily an endorsement for it as I've only measured one. It also doesn't seem to me that it's any finer than the dans black (and the dans black was about 2.65 or 2.7, I don't remember exactly).

That's why I commented that to me, anything in the 2.7 range or so is so lacking in pores that it's hard to tell which stone is more dense (which would suggest that it's not that important after a certain point).

Originally Posted by DaveW

That's why I commented that to me, anything in the 2.7 range or so is so lacking in pores that it's hard to tell which stone is more dense (which would suggest that it's not that important after a certain point).

There is a price difference amongst black arkansas at both NW and Dan's. I would not be surprised if around 2.6-2.7 is where the extra value/higher price comes in.

I've never purchased one of the NW black stones, which are fairly inexpensive if they don't have the "black trans" label applied to them.

Dans feels that the black is their finest stone, but I thought in actual use the trans was a tiny bit finer. They are both fine stones. I wouldn't be surprised if there wasn't a great deal of difference between the NW black and the dan's black, but I just haven't tried them as I only have the "black trans".

That said, anything that fine can eventually be made to work well by keeping the surface clean and wearing it through use. I've never had the opportunity to use a vintage black stone, either, which I have been told by some are better stones - but I don't know if they think that just because they're using stones that have had decades to break in and become very burnished (this is in regard to tools, too).

There is a large difference between the dans softs and the softs from other brands. I don't like dans softs much, they just don't cut very fast and part of it may be that their lapping process takes the aggressiveness out of them. The NW softs are much more aggressive to the point that what NW calls hard (big white stone) , but not black, trans or black trans, is a faster cutting stone than what dans calls soft.

Originally Posted by JimmyHAD

I take a razor and put it on a stone. It either works well or it doesn't, some are better than others. Like the old watchmaker told me when I asked him if 'this' is a good watch. Does it keep good time, he said, if it keeps good time it is a good watch.

I agree so much. I starting to pack up my self it's extremely time consuming cause I cleaning and oiling every straight with nortons honing oil. And I testing the stones I never really used I kind of bummed this one oil type stone I have seems dense and heavy one would think it's fine looking at it but it's terriable as for as sharpening goes and I used it with oil. It's kind of stinks cause I have gotten nicer stuff from rock piles littery.

Originally Posted by DaveW

All of the novaculite stones refuse to release particles in regular use, other than the odd particle here or there. The pike washitas at some point had stickers on the end that said "hard and fine" or "soft" and they may have said fast or something on the soft. In washita type stones (still novaculite, but a little different in structure vs. cheap soft stones), the smaller pore stones are definitely finer cutting and can finish a razor once settled in. Maybe the soft ones can, too, but I don't know that I have any cutting that slowly.

On eschers, there must be something in translation about how the barbers used the soft ones. I wonder if soft means self slurrying (which results in an edge that's not very fine if the edge is worked to) or if it just means a better feel. I had a y/g and it took a while to settle in. Anything that would've described it as soft (as a sticker on the end) was long gone. Compared to jnats and such, though, I was surprised how long it took for the escher to stop slurrying, and since I was sharpening the entire bevel all the way to the edge, it was immediately clear that while the stone was still slurrying, the edge wasn't what I'd want.

If Id have, however, worked to the edge, put the razor on the linen and strop, and then given a few more light strokes (which seems to be a decent recipe for a marginal stone), it probably would've been better.

long story short, softer is coarser, but softer really means less density and more space between abrasive clusters and the clusters themselves with the sharp edges from the space can do cutting. If the stone is more dense with less air space and relief for the particles and matrix to cut, then it cuts more finely.

One of the reasons, I think, that the pike washitas were so well loved by carpenters is because they are porous and those pores cut and never quite stop cutting. Cutting speed obviously being more important to a carpenter or cabinetmaker than to a single individual shaving with a razor.

I'd like to have a conversation with a high end barber in the late 1800s to see how they're using their stones and what they like. When I see a self slurrying stone, I always assume that anyone using it wants a fast cutter and isn't going to use it all the way to the edge of the razor for fear of making the edge more coarse.

But don't forgot simply using a honing oil that's of the right thickness prevents the stone from slurying and files in some of the low spots on the stone making a cheap or lowgrade stone cut and put a finer edge on a blade. That's why's some vintage De blades say on them honed with oil. Plus I tried putting oil on my Chinese 12k stone that I didn't like it now puts a better shaving edge on the razors.

Originally Posted by DaveW

I've never purchased one of the NW black stones, which are fairly inexpensive if they don't have the "black trans" label applied to them.

Dans feels that the black is their finest stone, but I thought in actual use the trans was a tiny bit finer. They are both fine stones. I wouldn't be surprised if there wasn't a great deal of difference between the NW black and the dan's black, but I just haven't tried them as I only have the "black trans".

That said, anything that fine can eventually be made to work well by keeping the surface clean and wearing it through use. I've never had the opportunity to use a vintage black stone, either, which I have been told by some are better stones - but I don't know if they think that just because they're using stones that have had decades to break in and become very burnished (this is in regard to tools, too).

There is a large difference between the dans softs and the softs from other brands. I don't like dans softs much, they just don't cut very fast and part of it may be that their lapping process takes the aggressiveness out of them. The NW softs are much more aggressive to the point that what NW calls hard (big white stone) , but not black, trans or black trans, is a faster cutting stone than what dans calls soft.

I bought a Vintage back a few years ago it's nice a little tiny bit of flatting but it's much finer then the clear black stone I just got that's the newly mined stuff.

Originally Posted by Suile

I bought a Vintage back a few years ago it's nice a little tiny bit of flatting but it's much finer then the clear black stone I just got that's the newly mined stuff.

Whether it was mined 'old' or 'new', if it is a genuine novaculite than both are around 350 million years old!

There are some that aren't genuine novculites, but they do not belong in this discussion.

The colour alone is not a measure of how fine the stone is.

I think Dan guarantees that his stones are all 100% genuine novaculite.

The purpose of honing oil is to carry away the swarf engendered during honing and keeping the 'pores' of the stone open (unclogged) BUT you have to use the right oil. If it is too thick it will let the stone clog up, if it is too thin it will let the stone clog up. In both cases this undermines the stone and makes it a much less efficient cutter.

Lapping the stone to a finer degree and burnishing it before use makes it a finer cutter and is better and more efficient than letting the stone clog up.

If you find better novaculites in rockpiles than the ones that Dan sells, you either got a really poor hone and should have sent it back or alternatively tell us where those rockpiles are!

Regards,
Neil