I have seen different opinions about what is the best way to flatten waterstones and so I decided to do a comparison. This is not meant to be a tutorial or to try to say I’m an authority on the subject(I’m not), so any thoughts or opinions are welcome.
I’ll try to just stick with what I started with and the different things I tried and basically my observations:
Stones
400 Naniwa Gouken Arata
800 King Neo
3000 Naniwa Gouken Arata
8000 Iminishi Kitayama
*F400 Venev Alpha Centauri
Knives
120mm(~5”) petty in SK-4
150mm(~6”) petty in VG10
200mm(~8”) carver/sujihiki in 4116
*Spyderco Native 5 LW in Maxamet
Flattening tools
220 grit silicon carbide powder on glass(450mm/18” square)
Atoma 400
Atoma 140
1200 grit silicon carbide wet and dry tile(400mm/16” square)
Before I start, I will say that this was the first time that I used SiC powder. I first started flattening my stones(years ago) with wet and dry sandpaper and later switched to mainly using the Atoma 140 and 400 depending on the stone. The surface finish for what I could notice between W&D and the Atoma’s is pretty similar depending on the grit used. I was pretty happy with both. The main advantage to diamond plate is how quickly it does the job.
When I got the SiC powder a couple weeks ago, I was surprised at how fine the powder was. I was expecting 220 grit to be visually coarser. As I used it I was also surprised at how quickly it took material off the stones as well. I only bought the 220 grit because I normally keep my stones pretty flat and from what I researched, quite a few people recommended something in that grit range (200-250) as a good finishing grit.
The TL;DR of the process I used was as follows:
I briefly refreshed each stone with diamond plates. The 400 Naniwa and 800 King I used the Atoma 140 and the 3000 Naniwa and 8000 Kitayama I used the Atoma 400. I rinsed the diamond plates clean between each stone. I used water on both surfaces and small circular motions with minimal downward pressure.
Next I blunted each knife on a paving brick a dozen times and sharpened each knife going through the grits before moving to the next knife. The exception was that I didn’t sharpen the carving knife on the 8000 Kitayama. I finished each knife with a very brief strop on 1 micron emulsion (Jende) on veg tanned leather on wooden backing.
I then blunted each knife again and refreshed each stone on the SiC powder on glass. I spread 1 tspn of the powder on the glass and sprayed a little water so that the grit was moving freely under the stone but not enough water that it ran off the glass. Again, small circular motions with little to no downward pressure maybe for 1-2 minutes each stone. I then repeated the sharpening on each knife in the same manner. It should be noted that I re-used the SiC powder for each flattening/refreshing. There were some people when I was researching that basically said that as you use the powder it gets finer and finer as you flatten finer grit stones.
After this, I refreshed the F400 Venev with Gumption(more on that later) sharpened the Native 5 and stropped briefly on the same strop, blunted it, then refreshed the Venev on the same SiC powder as before and sharpened and stropped again.
Naniwa Gouken Arata 400
I didn’t notice any difference with this stone. It seemed to cut at the same speed and felt the same whichever flattening method I used. The fastest flattening method was the Atoma 140, but the SiC powder wasn’t overly slow either. I would use something like 180 grit W&D sandpaper or even coarser if that was what you wanted to use.
King Neo 800
I did notice that holding the stone at the right angle in strong light you could see faint circular scratches on the surface with the Atoma 140, although you had to look hard to see them and were gone after a few passes. The SiC powder left a more uniform finish and was surprisingly fast at removing material from the stone(although not quite as fast as the Atoma). The feel and cutting speed whilst sharpening was the same from what I could tell. I don’t think for this grit it would make any difference for most people. If I was using W&D, I would again use something coarse like 180 grit give or take.
Naniwa Gouken Arata 3000
Another thing I came across when I was researching was some people basically saying that the advantages of using SiC powder is only really apparent on hard stones, so I expected this stone to be the one that could have different results. The other stones I have are softer (King 800 and Kitayama 8000) and/or coarse enough to not really make a difference(Naniwa 400 and King 800).
There was some really fine circular scratches that were very hard to see after using the Atoma 400. They were pretty much gone by the time I did a few passes in the area where I was sharpening. The finish from the SiC powder was more uniform but also a little rougher on the finger tips under running water. Perhaps at the very beginning of sharpening the first knife it felt rougher or coarser from the SiC powder, but after a few passes it felt more or less the same. I didn’t notice any difference in cutting speed of the stone. If I was using W&D, I would opt for something like 400 or 600 grit to refresh. Maybe something coarser to actually flatten and finish with 400/600 grit. It should be noted that this particular stone is very hard and would be very time consuming if you had to do any major flattening with W&D.
Overall I didn’t think there was too much practical difference between the SiC powder and the Atoma 400 on this stone.
Iminishi Kitayama 8000
This stone gave me the most surprising results. The finish from the Atoma 400 left faint scratches in the surface. Again, hard to see unless holding it at the right angle in strong light and looking carefully. Also, the scratches were only visible to the naked eye once it had started to dry. The feel of the surface under running water on the fingertips was smooth. The feel whilst sharpening was what I was used to, smooth and creamy.
After refreshing the surface with the SiC powder, the surface was noticeably rough under running water, although rough is maybe the wrong word. There was friction on the fingertips compared to the Atoma finish. Also visually it had a slight “pebbly” look when wet vs a more smooth look with the Atoma 400. The feel whilst sharpening was noticeably coarser, at least for a few passes until it smoothed out some. The visual pattern of the loading(this stone loads up much more than any of my other stones) was more coarse as well. I expected that after flattening three stones before it, the SiC powder might have broken down into a finer grit, but clearly not enough for this to work well. Without a doubt a finer grit SiC powder would work much better, but the 220 grit was inferior(especially if you are chasing a mirror polish) for this type of stone even after using it on 3 stones before it.
After sharpening the two knives on this stone, I got out some 1200 grit SiC W&D sandpaper on a tile(wet) and refreshed the Kitayama again, and it gave the best finish of the lot. The surface was buttery smooth, without visible scratches, and the sharpening feel and results from this finish was at least as good as the one from the Atoma 400. It must be said though, it would not be feasible to use 1200 grit W&D to flatten with. You would need to use something coarser and then finish with the 1200 grit if that was the way you wanted to go.
Venev Alpha Centauri F400
I have other Venev’s, but this is the grit I use most of the time to sharpen my(mostly high carbide) pocket knives. It’s a good balanced toothy finish(~600/700 JIS). Being a 6”x1”, it’s designed to be used in guided systems, but I use it as a pocket stone. I haven’t actually flattened it before, so I can only compare things I have tried when refreshing the surface. These stones tend to load up a little, but they also tend to glaze quite a bit as well after quite a few sharpenings. In the past I have used magic erasers, a rust eraser, Bar Keepers Friend and a product called Gumption. I’m pretty sure Gumption is only in Australia where I am, but I might be wrong about that. It’s basically a paste with the consistency similar to wet putty and is a mild abrasive multi-purpose cleaner. It is probably quite similar to a general purpose creme cleanser. So far I have found Gumption to clean the loading and glazing from these stones the best. Bar Keepers Friend also works really well. The Sabitoru rust eraser works pretty well, but is a lot more time consuming to remove glazing. Magic erasers work well to remove any loading but don’t do much to glazing. The magic eraser and rust eraser I consider good regular light maintenance options but after a while I need to use Gumption or BKF.
The SiC powder worked really well. It’s just as good as Gumption for refreshing and is the only thing I have used that will effectively flatten these stones quickly. I didn’t notice any difference in either the feel of the stone or the feel of the blade on the stone, nor the speed of cutting between SiC powder and Gumption. Gumption is just so easy though. Get a green kitchen scourer(I cut off a small piece to use for this) dip it in the paste, wet the stone and scrub the surface for 10-15 seconds and rinse and dry. I haven’t tried W&D sandpaper for this, although I suspect it would work well albeit slowly.
I’ll try to just stick with what I started with and the different things I tried and basically my observations:
Stones
400 Naniwa Gouken Arata
800 King Neo
3000 Naniwa Gouken Arata
8000 Iminishi Kitayama
*F400 Venev Alpha Centauri
Knives
120mm(~5”) petty in SK-4
150mm(~6”) petty in VG10
200mm(~8”) carver/sujihiki in 4116
*Spyderco Native 5 LW in Maxamet
Flattening tools
220 grit silicon carbide powder on glass(450mm/18” square)
Atoma 400
Atoma 140
1200 grit silicon carbide wet and dry tile(400mm/16” square)
Before I start, I will say that this was the first time that I used SiC powder. I first started flattening my stones(years ago) with wet and dry sandpaper and later switched to mainly using the Atoma 140 and 400 depending on the stone. The surface finish for what I could notice between W&D and the Atoma’s is pretty similar depending on the grit used. I was pretty happy with both. The main advantage to diamond plate is how quickly it does the job.
When I got the SiC powder a couple weeks ago, I was surprised at how fine the powder was. I was expecting 220 grit to be visually coarser. As I used it I was also surprised at how quickly it took material off the stones as well. I only bought the 220 grit because I normally keep my stones pretty flat and from what I researched, quite a few people recommended something in that grit range (200-250) as a good finishing grit.
The TL;DR of the process I used was as follows:
I briefly refreshed each stone with diamond plates. The 400 Naniwa and 800 King I used the Atoma 140 and the 3000 Naniwa and 8000 Kitayama I used the Atoma 400. I rinsed the diamond plates clean between each stone. I used water on both surfaces and small circular motions with minimal downward pressure.
Next I blunted each knife on a paving brick a dozen times and sharpened each knife going through the grits before moving to the next knife. The exception was that I didn’t sharpen the carving knife on the 8000 Kitayama. I finished each knife with a very brief strop on 1 micron emulsion (Jende) on veg tanned leather on wooden backing.
I then blunted each knife again and refreshed each stone on the SiC powder on glass. I spread 1 tspn of the powder on the glass and sprayed a little water so that the grit was moving freely under the stone but not enough water that it ran off the glass. Again, small circular motions with little to no downward pressure maybe for 1-2 minutes each stone. I then repeated the sharpening on each knife in the same manner. It should be noted that I re-used the SiC powder for each flattening/refreshing. There were some people when I was researching that basically said that as you use the powder it gets finer and finer as you flatten finer grit stones.
After this, I refreshed the F400 Venev with Gumption(more on that later) sharpened the Native 5 and stropped briefly on the same strop, blunted it, then refreshed the Venev on the same SiC powder as before and sharpened and stropped again.
Naniwa Gouken Arata 400
I didn’t notice any difference with this stone. It seemed to cut at the same speed and felt the same whichever flattening method I used. The fastest flattening method was the Atoma 140, but the SiC powder wasn’t overly slow either. I would use something like 180 grit W&D sandpaper or even coarser if that was what you wanted to use.
King Neo 800
I did notice that holding the stone at the right angle in strong light you could see faint circular scratches on the surface with the Atoma 140, although you had to look hard to see them and were gone after a few passes. The SiC powder left a more uniform finish and was surprisingly fast at removing material from the stone(although not quite as fast as the Atoma). The feel and cutting speed whilst sharpening was the same from what I could tell. I don’t think for this grit it would make any difference for most people. If I was using W&D, I would again use something coarse like 180 grit give or take.
Naniwa Gouken Arata 3000
Another thing I came across when I was researching was some people basically saying that the advantages of using SiC powder is only really apparent on hard stones, so I expected this stone to be the one that could have different results. The other stones I have are softer (King 800 and Kitayama 8000) and/or coarse enough to not really make a difference(Naniwa 400 and King 800).
There was some really fine circular scratches that were very hard to see after using the Atoma 400. They were pretty much gone by the time I did a few passes in the area where I was sharpening. The finish from the SiC powder was more uniform but also a little rougher on the finger tips under running water. Perhaps at the very beginning of sharpening the first knife it felt rougher or coarser from the SiC powder, but after a few passes it felt more or less the same. I didn’t notice any difference in cutting speed of the stone. If I was using W&D, I would opt for something like 400 or 600 grit to refresh. Maybe something coarser to actually flatten and finish with 400/600 grit. It should be noted that this particular stone is very hard and would be very time consuming if you had to do any major flattening with W&D.
Overall I didn’t think there was too much practical difference between the SiC powder and the Atoma 400 on this stone.
Iminishi Kitayama 8000
This stone gave me the most surprising results. The finish from the Atoma 400 left faint scratches in the surface. Again, hard to see unless holding it at the right angle in strong light and looking carefully. Also, the scratches were only visible to the naked eye once it had started to dry. The feel of the surface under running water on the fingertips was smooth. The feel whilst sharpening was what I was used to, smooth and creamy.
After refreshing the surface with the SiC powder, the surface was noticeably rough under running water, although rough is maybe the wrong word. There was friction on the fingertips compared to the Atoma finish. Also visually it had a slight “pebbly” look when wet vs a more smooth look with the Atoma 400. The feel whilst sharpening was noticeably coarser, at least for a few passes until it smoothed out some. The visual pattern of the loading(this stone loads up much more than any of my other stones) was more coarse as well. I expected that after flattening three stones before it, the SiC powder might have broken down into a finer grit, but clearly not enough for this to work well. Without a doubt a finer grit SiC powder would work much better, but the 220 grit was inferior(especially if you are chasing a mirror polish) for this type of stone even after using it on 3 stones before it.
After sharpening the two knives on this stone, I got out some 1200 grit SiC W&D sandpaper on a tile(wet) and refreshed the Kitayama again, and it gave the best finish of the lot. The surface was buttery smooth, without visible scratches, and the sharpening feel and results from this finish was at least as good as the one from the Atoma 400. It must be said though, it would not be feasible to use 1200 grit W&D to flatten with. You would need to use something coarser and then finish with the 1200 grit if that was the way you wanted to go.
Venev Alpha Centauri F400
I have other Venev’s, but this is the grit I use most of the time to sharpen my(mostly high carbide) pocket knives. It’s a good balanced toothy finish(~600/700 JIS). Being a 6”x1”, it’s designed to be used in guided systems, but I use it as a pocket stone. I haven’t actually flattened it before, so I can only compare things I have tried when refreshing the surface. These stones tend to load up a little, but they also tend to glaze quite a bit as well after quite a few sharpenings. In the past I have used magic erasers, a rust eraser, Bar Keepers Friend and a product called Gumption. I’m pretty sure Gumption is only in Australia where I am, but I might be wrong about that. It’s basically a paste with the consistency similar to wet putty and is a mild abrasive multi-purpose cleaner. It is probably quite similar to a general purpose creme cleanser. So far I have found Gumption to clean the loading and glazing from these stones the best. Bar Keepers Friend also works really well. The Sabitoru rust eraser works pretty well, but is a lot more time consuming to remove glazing. Magic erasers work well to remove any loading but don’t do much to glazing. The magic eraser and rust eraser I consider good regular light maintenance options but after a while I need to use Gumption or BKF.
The SiC powder worked really well. It’s just as good as Gumption for refreshing and is the only thing I have used that will effectively flatten these stones quickly. I didn’t notice any difference in either the feel of the stone or the feel of the blade on the stone, nor the speed of cutting between SiC powder and Gumption. Gumption is just so easy though. Get a green kitchen scourer(I cut off a small piece to use for this) dip it in the paste, wet the stone and scrub the surface for 10-15 seconds and rinse and dry. I haven’t tried W&D sandpaper for this, although I suspect it would work well albeit slowly.