Double Ground Usuba

me2

Well-Known Member
Is there such an animal? I want to try one but dont have the gear for a proper hollow relief on the back. Is a 2° back bevel an acceptable alternative, or a full double grind, n/either one?
 
I have a kurimuki I'm working on with that backbevel. If that works I'll try it with a usuba.
 
Usuba and Nakiri are quite different animals. Nakiri is a all purpose veggie knife, like a gyuto without a tip. A Usuba is primarily designed for a katsuramaki cut. Usuba is generally a thicker(4-6mm on spine) single bevel knife, with the nakiri being double bevel. With that being said, the 2 degree back might work pretty well. The urasuki grind is to keep a keener edge bevel while reducing sticking. I would experiment and have fun :) and as they say, pics or it didnt happen. Just for reference, this site http://zknives.com/index.shtml is a great source of info on japanese style kitchen cutlery.
 
The normal Usuba and Nakiri have the EXACT same blade shape/profile. If he wants to make a double bevel Usuba, that is what a Nakiri is. Usuba's are slightly thicker, which allows the Ura to be ground in and with the single bevel/hollow back, they don't need to be thin to cut well. A nakiri is thinner because the extra thickness isn't needed to do the hollow on the back.
 
Sorry Taz, wasn't saying they weren't similar, they are quite similar. They are just used for different things. I would hate to have to grind a 5mm thick nakiri lol. And i never implied that thin is the only way to cut well. I owuld say if you want to make a nakiri style, maybe a 3/32 steel would be the best choice, so you can maintain a nice, thin cutting machine. One thing i would suggest is the HT before grinding bevels, in stock that wide/thin, you run into more warping issues. And just for fun, i will show a picture of a failed usuba HT. 1095...crazy.
2013-01-12_22-12-55_440.jpg
 
The steel is already hardened. Zknives is my main source of info. I was under the impression a usuba was a general use knife, not specialized for katsuramuki. My steel is 3/32" thick, but a full flat grind nakiri isnt an option. Whatever it ends up being it will be saber/partial height grinds.
 
Saber grind is fine for a Nakiri type knife. The Usuba can do more than just the katsuramuki, but a true Usuba is a bit harder to sharpen and due to the crazy thin edge, it easier to damage. If you want a general purpose type knife, do up a Nakiri with a double grind, saber, flat, convex, asymetrical, whatever you like! With 3/32" thick steel, it will get nice and thin down near the edge. I took a 1/8" thick blade, around 2" wide or so and did a convex grind halfway down the blade to the edge on both sides, cut wonderfully! Unfortunately the Damascus steel that the blank was made out of had some bad welds and the blade ended up cracking during use at the bad weld marks. I got the blank for nothing, and it was great practice grinding a blade like that!
 
Do nakiri and usuba use the same high hardness steel as other Japanese style blades?
 
They can be, or they can be a bit softer. Most I have seen are between 60 and 64 rockwell, depending on the steel and what the steel's optimum hardness is for the application. My Terayasu Fujiwara Nashiji Nakiri is supposed to be a White #1 core at 63-64 Rockwell, not sure about my Tanaka Blue #2 Kurouchi or Tojiro ITK Shirogami White #2. Using a steel like 1095, 60 would be about right I think. Higher hardness doesn't always mean better since it may make the steel too brittle.
 
Well, what steel is it? It may be OK at that hardness? Do you have access to an oven or toaster oven or something to temper it back or is it a steel that needs to be much higher to temper?
 
I would toss it in the oven at 325-350 for 2 hours. That should yield around 61-62 rockwell. I persinally feel 64-66 is far too hard for 1095 and it will be very brittle...almost to the point that if you drop it, the is a very good chance it will break. I would say a saber grind at half height on 3/32 will make a very thin edge and one wicked cutter. Again...pics :)
 
It's M2. Less than 1050 F won't do me any good. It is surprisingly tough at such a hardness. I made a test blade of it a couple years ago (puukko style) and dug a hole through a 1x6 and was able to baton with it using a hammer and it didn't break, but it did dent the hammer face. That piece was 0.05" or so thick. In hind sight it would have made a great small petty.
 
Hmm. That may be OK for M2 looking at other info on the web about M2, but it may chip if you hit the board hard when chopping veggies. How do you plan on grinding on the hardened steel; I hope you have access to a variable speed belt sander or water cooled grinder or cnc of some sort!
 
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