Using oilstones

[David Weaver]

Scratch patterns will look similar between the two. Stropping on bare leather and paring some will tell you more.

[David Weaver]

Let me illustrate some, apologies that some of these pictures are poor. I posted these a long while ago on a razor forum when I was trying to find the differences between washita, hard ark, chinese agate...

Here is the edge off of a bone colored ark...this is my favorite old stone, though it's just a tad coarser than something like a new dans trans. I call it "magic wonderstone", but I think anyone who tries it thinks "I wonder what's so magic about it, because I don't get it :

rotation.jpg

Left to right:
*a soft smiths type stone (very cheap stone, very coarse, sometimes labeled washita but not similar.
* razor washita (like a lilywhite type but finer)
* hard ark
* green chinese agate (finer than hard ark, but probably due to softer abrasive particles)

The pictures are shown with a cheap microscope that has LEDs right at the lens. How they are interpreted by the software seems to be dependent on the reflecting light, so the lighting level varies in the pictures like it wouldn't do with a better scope. Also, the scope reflected light shows scratches where other pages (tim zowada's for example), would show a polished surface. Past the soft, all of the surfaces look like some level of polish with the last two stones leaving what looks like a bright polish, so the scratches shouldn't be interpreted as coarse scratches, they are exaggerated by the light.


The edge from the washita (keeping in mind this washita has been allowed to settle in - someone else had been using it for razors before I got it):
washita1.jpg

the edge from the hard...

novac11.jpg

And then after some traffic on the chinese stone:

agate.jpg

[David Weaver]

(these edges are all prior to stropping...if I used graded chromium oxide powder, I could remove the scratches and leave a dull dark looking surface, but the shave isn't any better because the actual edge isn't any thinner, and the little bits and pieces at the edge are removed by the linen).

soft surface.jpgwashitasurface.jpgnovac surface.jpgagate surface.jpg

Surfaces of the stones left to right, soft, washita, hard ark, chinese agate.

The agate surface isn't instructive, it's still got scratch marks from lapping in it. It's an odd stone that I don't like very much, as it has a lot of potential to polish something, but it's extremely slow and it sometimes releases big particles that bruise edges. It feels like honing on hard oiled rubber, it just doesn't do much other than chase a burr. You can see under the lines, though, that it has some bubbles in the matrix...it's just a bizarre stone that's capable of a finer edge than the arks, but at the cost of major fiddling.

[David Weaver]

The strange thing shaving with these stones is that the washita is borderline for shaving, but if after preparing the edge you shave once with it and then take a few very light strokes with the razor on the stone and hit the linen again, the edge is as keen and smooth as any other natural stone, which suggests it's a fairly close stone to the hard arks.

If your washita is close to a hard ark, then that's just what it is. Even from the coarse washitas, if they're allowed to settle in, you can get a better edge off of them than any medium synthetic stone.

[Kees Heiden]

Ok, so the microscope is out. Maybe mine can get a little better images though. I'll try it anyway. Those oilstones are really difficult to wrap my head around! I guess only accumulating vast quantities of stones will give me better insight.


In the video from the Raggenbass planemakers in Switserland you can see the "young" Raggenbass wetting a plane iron from 10:57 onwards. He switches from front to back all the time. Is that how you adress the burr issue?

http://www.rts.ch/archives/tv/cultur...s-de-bois.html

[David Weaver]

Ok, so the microscope is out. Maybe mine can get a little better images though. I'll try it anyway. Those oilstones are really difficult to wrap my head around! I guess only accumulating vast quantities of stones will give me better insight.


In the video from the Raggenbass planemakers in Switserland you can see the "young" Raggenbass wetting a plane iron from 10:57 onwards. He switches from front to back all the time. Is that how you adress the burr issue?

http://www.rts.ch/archives/tv/cultur...s-de-bois.html

Yes. I don't know what right term is for it, but I call that thinning the burr. Switching from front to back to make the burr less strong - resulting in an edge that strops to smoothness on bare leather very easily.

If you have some wear to remove and need to create a significant wire edge to show that you've done a lot of work, I would do the entire amount of bevel work first, then work the back heavily and then do light alternating back and forth (I didn't watch before the time you mentioned to see if he did any heavy work on the stone, but I'd suspect not).

[Kees Heiden]

No he goes from a big grinder to this stone. He doesn't even strop. When I look at that I feel that I am thinking way too much about this sharpening thing...

[David Weaver]

Force yourself to use only that washita for a while, and you'll be surprised how good you get using it. Seriously, it's not a bad way to go and it certainly doesn't add any time to woodworking.

[Kees Heiden]

Good idea.

At the other hand, there is a real vintage Norton translucent winking at me.

[Kees Heiden]

Another quickl question. When searching for Arkansas stones overhere I see lots of places selling a black stone with a label "Original Arkansas". What brand would that be?

Example:
http://www.mehr-als-werkzeug.de/prod...tone-Black.htm

[David Weaver]

That's just branding "original arkansas"....and an errant statement about scarcity of black stones. There is no shortage of black arkansas stones that cut finely. Translucent stones from vendor to vendor vary a little bit (you can tell a dan's trans vs. a norton, they come from different locations and dan's trans is more like norton vintage than norton is). If there's any shortage, it's that the trans stones are a little harder to find vendor to vendor, at least cheaply.

If you can get a vintage norton translucent bought at a reasonable price, you'll never lose money on it and it will be definitive about what you can expect from the stones.

For what it's worth, that branding "original arkansas" might be there to differentiate the stone vs. bonded stones, etc, or slates that people might mistake visually for an arkansas stone....who knows. Like mentioned earlier, if a stone has specific gravity in the 2.6-2.7 range, which is where most trans and black stones are, it signifies a lack of pores and they will all cut similarly once the surface treatment they were given (sawing/lapping) wears away.

[Kees Heiden]

Thanks for the insight David.

[Kees Heiden]

So I finally got around to set up the microscope and make a few pictures. Not that it tells me much, but anyway, here they are. Magnification 470x.

First the oilstones on a Berg chisel. This has much better steel then the moulding plane irons I was working of late. It doesn't raise such large burrs and they are easier to get rid of. First I hone with the washita, rising a good burr.

oil wash with burr.jpg

Then onto the arkansas at a higher angle which reduced the burr a bit. I didn't do more to remove it before I made this picture. I would say that the Arkansas is indeed a little finer then the washita. But I wonder if that is all I can get from an oilstone? Nothing finer available?

oil wash - ark.jpg

To make the comparison complete I got another Berg chisel and did the same with a 1000 and a 8000 grit waterstone. It was hard to take a picture because the surface is so reflective. My microscope has a polaroid filter and I could turn the filter untill I got this pitcure just inbetween too dark and way too light.

Water 1000-8000.jpg

So, the different look is partly because of the difference in lighting, but also because of the difference in how the grit works. I would say that this 8000 grit stone is finer then the arkansas.

Drawing conclusions from microscope pictures is very hard. Often you just don't know what you are looking at. I tested both chisels after working the burr, on a piece of endgrain fir. They both paired cleanly, but the waterstone sharpened one feels sharper. Even stropping on the flexcut paste doesn't imrpove that. I wouldn't draw conclusions from that either because I am still at the beginning of the oilstone path.

I do think that I can conclude that my Arkansas makes the edge finer then the Washita. I don't know if this is the best Arkansas available on earth, but it'll do for a while. Just for giggles, here are pictures from the two oilstones.

Washita:

Washita.jpg

Arkansas:
ark trans.jpg

[ken hatch]

Kees,

Of course color isn't a good indicator of oil stone hardness or fineness but your Arkansas looks just like my Soft Arkansas from Dan's.

ken

[Curt Putnam]

Kees, knowing that you are good at research, I'll just throw this out for consideration (do your due diligence.) I have read, or think I have read that the difference between the grades of stones is not grit, but density. To me (I'm stretching here), that means that the difference for sharpening comes down to speed of particle release, which equals honing speed. Hence the importance of stropping in oil stone use.

I think I've missed something and hopefully one of the experts will chime and correct my thoughts. Failing that, perhaps you could do the research and post the results here.