How To Get The Most Out Of A J-Nat

Discussion in 'Hones/Honing' started by raccoonandbrush, Dec 29, 2011.

  1. I am new to Japanese natural stones. I have done a good amount of reading about them, but I still have some questions. I've read that using a Nagura stone on the J-Nat breaks down the particles of the stone, making it even finer. I thought slurry stones make hones more coarse?
     
  2. I believe what happens is the Nagura on the JNAT makes a coarser slurry than the JNAT with water. The Nagura slurry eventually breaks down and slowly becomes finer. This results in a Slurry that starts coarser and becomes finer leading you into where you will use water only to finish.
     
  3. Kentos

    Kentos Moderator Emeritus

    Your are right, it does make it more coarse. Depending on what stage your are in your honing, you would use nagura to bridge the gap to finishing, or if you are the finishing point already then just on water. Jnats are like 80% black magic in my opinion...moreso than coticules. It took me a while to get a good edge on mine. My best edges so far involved 0.05 poly diamond spray...but I'm a rebel :)
     
  4. I haven't seen Nagura making the surface of the stone less fine or more coarse.
    But - Botan Nagura slurry is more coarse than the slurry obtained from using the Tomo Nagura.
    The stone is harder than the Nagura - the slurry comes from the Nagura. With Tomo nagura, it's equally hard as the stone, and all I see is a polishing effect on the stone.
    Maybe I'm wrong - but that's how it seems to me so far. I'm new to these stones also, and I'm learning as I go.
     
  5. Kentos

    Kentos Moderator Emeritus

    I guess I should have said that the slurry makes the stone cut more, but the stone stays the same regardless.
     
  6. Isn't that the same thing as using a coarser stone?
     
  7. Kentos

    Kentos Moderator Emeritus

    Well, technically speaking the characteristics of the stone remain the same. Kind of like lapping powder on a glass plate. Adding the powder to the glass doesnt make the GLASS coarse. Wipe off the powder and the glass iis still smooth, albeit a bit scratched up. I guess its just semantics.
     
  8. Kentos

    Kentos Moderator Emeritus

    I should add my understanding of nagura honing is the initial slurry is "coarse". As you take your laps the slurry slowly breaks down to finer and finer particles until you are left with just the final grit of your stone, or maybe a bit lower. Some then wash off the slurry and finish on water for even a finer edge...YMMV of course. Coticule slurry doesnt breakdown as readily, so dilution of the slurry is needed to reduce the cutting action of the slurry.
     
  9. I see.
     
  10. the base stone should be harder than any nagura or tomonagura used on it. When you work the slurry from the nagura/tomonagura it will gradually break down to become muc finer. You can finish on the base stone with water or if you like.
     
    Last edited: Dec 31, 2011
  11. I was under the impression that base stone should be harder than any nagura as you say, but that the tomonagura should be harder in order to hone on slurry released from the base stone itself. :confused1
     
  12. Kentos

    Kentos Moderator Emeritus

    Tomonagura means, same, together, or friend nagura...so that way maybe it wont matter which stone release the slurry? :confused1
     
  13. ^ It seems to be relatively seldom that the tomonagura in question is actually cut from the same stone. It kinda does matter (to me, anyway...) that the slurry I'm using should - under 'normal' circumstances - ideally come from the expensive and hopefully high-quality hone itself. Having said that, I have not yet found anything harder than my finisher and that won't barely even raise a detectable slurry anyway (but it's not needed....:wink2:). On a pre-polisher, I use a hard suita tomonagura which does the trick for me. But like I said...that's just my thinking.
     
    Last edited: Dec 31, 2011
  14. you need the base stone to be the hardest stone in the system.
     
  15. From what I gather in Japan they do not cut slurry stones from the main stone. I have seen only one exception so far, and that was done by the owner after they purchased the stone.
     
  16. Kentos

    Kentos Moderator Emeritus

    So if I am having trouble getting a slurry going with my tomonagura I need a softer nagura maybe? Or
    maybe just more practice
     
    Last edited: Dec 31, 2011
  17. what are you using? Do you have a pic?
     
  18. Kentos

    Kentos Moderator Emeritus

    Here is my no name Japanese hone. My Father bought it 20 years ago when we lived in Yokohama...I think it was 10,000 yen. It also just occurred to me that the nagura is a Oozuku tomo, and not the same as the no name rock, so that may be my problem...either way unless i really bear down on the nagura with pressure I get nothing...and even then I just barely can see anything in the water...although there is an earthy smell. Maybe I dont need much slurry at all and I am trying to hard. The surface is very smooth, and semi reflective when dry- I cant see my face it it, but if i look at a very shallow angle i can see my surroundings in it.
    [​IMG]
     
  19. The pattern on your rock Kentos points to it being a Kan but the color / mine may be tricky but if we compare colors to one at Japanese Natural Stones it looks similar to an Ozuku Kan. http://www.japanesenaturalstones.com/ProductDetails.asp?ProductCode=327 It may even be a Wakasa Kiita/Kan because it has the same color, spotting and if you look closely it has a rust colored kan (ring) pattern. http://www.japanesenaturalstones.com/SearchResults.asp?Cat=1821 Maybe you should contact him and see if he can identify it and recommend a different Nagura?
     
    Last edited: Jan 1, 2012
  20. Kentos

    Kentos Moderator Emeritus

    Thanks for those links Cyi. I contemplated getting a true tomonagura, but have had good results with the untraditional, somewhat sacrilegious use of nano diamond sprays in place of slurry for finishing :scared:.
     

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