Contributor
Here's an example, this is an Hindostan stone, the pictures show the before and after of using 90x SiC grit.
20221105_123431 (1).jpg20221105_130404 (1).jpg
P.S. All my stones are held in wooden boxes and are cleaned with oil after use. That avoids getting them dirty.
Contributor
For kicks, I flattened the stone one end with #240 diamond plate, & the other end with #400 diamond plate,
then worked a chisel 1/2 on each end of the stone. Looking for a difference in the scratch pattern including with a little 40 power hand microscope.
At moments I thought I could see a difference, but at other moments not.
Contributor
The cutting power depends on the pressure you apply. Try pressing harder.
Contributor
Originally Posted by Rafael Herrera
I was looking in to Warren Mickely's and your idea that abrading a stone with a coarser abrasive would make it perform like a different stone, so I used the same pressure on each.
Contributor
A former co-worker was into knives. He told me when using oilstones, "press the blade into the stone like you mean it."
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
Contributor
The above does not mean that that's how the oilstone must always be used. Pressing harder results in more aggressive grinding, pressing less is more Ike polishing. Over time a stone settles, if the use w varying degrees of pressure gets you the edge you want, then dressing the stone becomes unnecessary.
Contributor
If I remember correctly, Lee Valley sells Formax, which is my preferred brand just because I know it. In other words, it is not that I found other lacking, but I have heard reports from others of compounds they did not like but Formax is a known entity. Also, if Lee Valley sells it, you can be sure it is fine.
My chart indicates that Green Compound in general is around 0.5 Micron, which is roughly 50,000 to 60,000 grit. Chromium Oxide (Cr2O3) is a superfine, polycrystalline abrasive, it is the mineral that gives green polishing compound it’s color.
Note that the Tormek Honing Compound is roughly 3 microns (8000 grit).
Some people strop on leather, some people strop on wood.
I even have heavy concentration 1 Micron Diamond Spray that I can use to make a hone. Have not tried it yet, too busy.
Member
You're overthinking this. Comparing grits with waterstones doesn't really tell you anything about your future sharpening, since waterstones are targeted at a particular type of steel and in general waterstones behave differently from oilstones. One particular oilstone can be set up for a range of coarseness for example. A freshly flattened India is faster cutting than an India stone that glazed a little bit over time, so you can decide how do you want it. My set up is similar to Ron's, except I've got a "big gray" crystolon stone from Sharpening Supplies. It doesn't stay flat, not even close, but this stone has areas which remove steel fast and a few spots that I keep that produce a bright mirror polish - all on the same stone. In terms of coarseness you can let your India stone to get pretty close to the soft ark. It leaves cloudy finish (meaning scratches, meaning it's still abrading rather than polishing), but a burr can pop off on an India stone. Some days I skip an arkansas and go straight to a power buffer and it works wonders. So this brings my protocol to just two stones, and only sometimes three. If a tool was freshly ground it's 400 diamond + India + power strop, otherwise it's crystolon + india + power strop. An arkansas (or rather washita) is used when I strop manually.
In terms of economy the only option for less money than Norton is some no name/no brand "made in USA" sharpening stones. They look exactly like Norton minus the print on the side. The vendor somewhat proudly grumbled it has nothing to do with Norton. These stones are okay, it's just I can't tell whether they're all okay or I just pulled lucky two stones. But at 25$ for an India combo stone I wouldn't probably experiment. Btw if you decide to buy combo stones - get two. My biggest issue with combo stones is coarser grit contaminating finer grit, so somebody told me that people used to buy them in pairs and use only one side on every stone. Once the side is worn stones were flipped (apparently never judging by combo stones full of life on ebay).
Personally, if years back I knew what I know about oilstones I would go with Norton's tri-hone, arkie version. Always fascinated how David W could pull one on a workbench, quickly sharpen and stow away, quickly and with little fuss. My setup takes a whole 22" x 36" area, which is like 20% of my shop space atm.
Member
I think you're just forgetting the fact that JIS grit chart just has a different scale than ANSI\FEPA. Not a well known fact apparently, judging how often people repeat the point that Arkansas stones are in the "grinding" range. In simple words, ANSI 1200 grit abrasive IS NOT equivalent to the JIS 1200 grit, neither is 8000 JIS eight times finer that DMT 1000 diamond plate. To get some vague idea about coarseness a grit particle size could be compared, most grit conversion charts list the size along with the scales.
The scales are different because there's different ways to ensure average grit size, so all three scales are drifting away from each other.
Contributor
How do you flatten your crystolon? Loose grit on float glass? I have only done it a few times but it has been long enough back I am a bit fuzzy on what I did. I think I used loose grit.
I bought one but never tried it. I met someone who needed a sharpening stone so I gave it to him.
I think that I would simply buy a single grit stone since they do sell them. I like the combo stones when I am heading out and only want to bring a single stone (does not happen often).
I have the version with two crystolon and one India stone. I really like it. I think I can get:
- Norton Soft Arkansas (about $60)
- Norton Hard Arkansas (about $80)
- Norton Hard Black (about $250)
- Norton Hard Translucent (about $260)
- Norton Ascent Ceramic Fine ($280)
- Norton Ascent Ceramic Ultra Fine ($300)
- Dan's Soft ($60)
- Dans Hard ($79)
- Dan's Hard Black ($250)
So many choices.
My primary complaint is that the IM313 does not travel well because of the oil well and things are not sealed. Works really well in the shop, however. If the shop is not heated, I am not sure how the oil will hold up to freezing. But if you simply have a small footprint, this works really well for me, but I do not have arkansas stones in mine.
Contributor
I was given one of those- IM313 stone set, recently. It was unused in original box with retail price sticker (remember those?) for $107, less than half of today's.
I sold it- seemed like it's best use was in a restaurant, sharpening kitchen knives.
Member
A very simplistic model for sharpening has you using finer and finer "grits" and the fineness of the last grit characterizes the degree of sharpness. A more sophisticated model considers the depth of scratches a stone makes. Harsh abrasives (fast cutting) leave deep scratches and a weak edge.
Arkansas stones that are in good shape have a flat surface with tiny crevices. The crevices get caught on roughness on the tools bevel and remove them, but once the tool is polished they barely cut. So they leave just very shallow scratches in contrast to harsh abrasives. Abrading an Arkansas stone with anything causes degrading of the stone.
Contributor
I think this is the first sharpening thread I’ve enjoyed.
If I recall correctly Toshio Odate’s book on Japanese tools has some microscope pics of western tool steel sharpened at like 2 micron or equivalent on different stones as well as pics of the different stone structures. The natural water and oil stones clearly had much more rounded particles and left a much less serrated edge.
That being said I think he was most interested in getting back to work so soft synthetic water stones were used.
I have a tsushima stone that is interesting. With fresh slurry and some pressure is sharpens like a 2k synthetic and cuts pretty quickly. If you work the slurry for a while and reduce pressure it leaves a 8kish polish.
This thread inspired me to clean up some of the nicer oil stones I have. One is quite fine and came in a dugout mahogany box. Hope to share here next time Im in the shop and can take a pic.
Contributor
Sometime ago, on another forum, there was a long thread on the Unicorn treatment, edges and edge failure.
Someone linked to a site with a study of edges and edge failure. In the context of woodworking it was noted that an edge fails faster if the edge's scratch pattern is deep. The metal will fatigue sooner and crack than when the edge sides are smother. The Unicorn method was presumed to improve the stability of the edge by smoothing the sides of the edge. David Weaver posted several articles in his blog about how different steels wore out over time. An exotic steel isn't necessarily superior to simpler steels if the later is properly sharpened.
Another take away from that thread that I found very useful was that chisel usage technique contributes to edge life. Prying motions while using a bench chisel will cause premature edge failure. I think that was contributed by Warren.
Contributor
Pardon my picking this apart, but this suggests that all Arkanasa stones are degraded, having been honed, and If one thinks flattening will do damage, then used stones are not in good shape, since they are not flat.
The idea that a stone cuts a rougher surface but stops cutting on a smoother surface sounds rather magical.
Posting Permissions
Reply With Quote