Sun Aug 05, 2012 9:12 am
I got a chance today to work with some stones I recently got from CKTG. I got an Amakusa, Shobu San and a Kyushu Ohmura. I also got one of the Aoto's in my last order, which is a combination of synthetic and natural stone material. I started with a coarse diamond stone to flatten the bevel on my Tanaka Blue #2 Nakiri and a Fujiwara Terayasu White #1 clad Nakiri. I wanted to thin the Terayasu out a tad since I have never thinned it in the several years I have sharpened it. I decided to try to flatten the blade roads/bevel leading to the edge since I have never done that before on any of my KU style knives.
From the diamond, I went to the Kyushu Ohmura. It worked well and removed material cleanly, but was a bit slower than I thought it would be. It gets very muddy though, and this helps polish as you grind material away. Next, I went to the Amakusa, which is a 800-1000 grit stone. Got muddy, but felt really nice to work and worked pretty quickly on the blades. Left a nice scratch pattern. I moved to the Aoto and got to play in the mud. It gets nice and muddy and works slow, but that's because it's also polishing. It left the edges with a nice contrast between the clad and core steels (Blue #2 and White #1). The Shobu San was up next and it was fun to work. It's a narrower stone, but still worked really well and had a great feel to it. Very smooth feeling and refined the contrast a bit more and also put a very nice edge on the blades. I used the Shobu San to clean up the edges and then went to the Ozuka Asagi Koppa and used that to finish off the edges. I tried it on the blade roads, but it was slow cutting and cleaned it up a bit, but I wasn't too patient with it. As I progressed through the grits, it just made the deeper scratches from before that I didn't get out stand out more, so I wasn't concerned with the finish as much. The stones seemd to work smoother and left cleaner finishes on the Tanaka cladding vs the SS cladding on the Fujiwara Terayasu. I took the Fujiwara back down to the Rika 5K to work the edge a bit more and then back up to the Ozuka Asagi. I also worked the blade road on the Rika 5K and it did a nice job cleaning it up and really polishing up the harder core steel. It left a very nice finish on the harder steel.
I really enjoyed the Amakusa and Shobu San a lot!! The Kyushu Ohmura will work well for getting chips out of blades, but I am going to search a little more for another even coarser stone to flatten the blade roads a little quicker. The Kyushu Ohmura feels coarse, but seems to build up a nice mud and cut a bit slower than I was hoping, but this means that there aren't as many coarse scratches to take out with the finer grits, too! I would say maybe around 500-800 grit range possibly, but it finishes a bit finer when the mud builds up?? The 3 stones, plus the Aoto and Ozuka Asagi are my main jump into J Nats and I am very happy with all 3 of them!!
Thu Oct 25, 2012 9:02 pm
A next coarser natural stone than the Kyushu Ohmura is the Hirashima a truly coarse stone. You might also consider the 150 Nubatama or even go a bit coarser if necessary with the 120 60 or even 24 grit stones. IMO these are too coarse for a Nakiri and the 150 will do a superb job of reprofiling a nakiri. Then follow it with your naturals.
Thu Oct 25, 2012 9:15 pm
I got a Nubatama 150 a while back and like it. It cuts pretty fast, but leaves a cleaner scratch pattern than my 200-600 diamond plates I have. Haven't tried it on the Nakiri and other blades yet, just AEB-L and M390.
Wed Nov 07, 2012 3:17 pm
I'm working with the Nubatama 150 right now as well. I like it. Fast as lightning and wears pretty slow for a low grit stone.
Wed Nov 07, 2012 11:14 pm
I haven't gotten a chance to use the Nubatama much lately. I figured out how to use my rotary platen to thin and convex edges