Page 1 of 2 12 LastLast
Results 1 to 10 of 12
Like Tree30Likes

Thread: Burnishing and Jnats

  1. #1
    Senior Member
    Join Date
    May 2014
    Location
    Knoxville, TN
    Posts
    1,346
    Thanked: 415

    Default Burnishing and Jnats

    The Arkansas threads have gotten me thinking about surface finishing, on hard jnats.

    If you look across the fora, you’ll get different answers to how fine/smooth a jnat needs to be finished.

    You can find posts that say ‘not that fine, in a few strokes it wears down’, or ‘not that fine and smooth it with a nagura’ - which I do for the record. And you can find others that smooth to 2k sandpaper or so, which I also do, well 1500 or 2k, whatever’s out on the bench.

    But I have some jnats that are really, really hard. Not Ark hard of course, but with a tomo of equal hardness it will take 3 minutes or so to raise a light slurry with moderate to heavy pressure. They glaze to some extent, like an Ark maybe. I can de-glaze the stone (and nagura) and it works faster, but does a hard, glazed, jnat act finer like a hard burnished/glazed Ark? I think maybe a glazed hard jnat does finish finer than an unglazed one, but thought that I’d throw out this question for the jnat folks. Oz, Stefan?
    My doorstop is a Nakayama

  2. #2
    Senior Member
    Join Date
    Jan 2015
    Location
    Apex NC
    Posts
    478
    Thanked: 76

    Default

    I feel that on really hard Jnats the stones do benefit from that finer smooth finish. On the ones that aren't that hard you can remove the lighter scratches with nagura from the stone so it is resurfacing itself and fixing those before the blade hits them. On the harder stones not so much. Plus on the harder stones those sharper edges from scratches even the ones you can't see are not giving like a softer stone on that edge. I know there is alot more going on here with the surface friability and hardness too. The nagura with also make a difference of course.

    I have to agree from my experience.

  3. #3
    Senior Member blabbermouth
    Join Date
    Dec 2014
    Location
    Virginia, USA
    Posts
    2,209
    Thanked: 479

    Default

    Will it work similar to an Arkansas, and polish finer if well burnished? Sure. But every time you rub a nagura over the surface, you're disturbing that burnish by releasing some of the surface grit on the hone whether you're using Tomo or something softer. So...are you willing to burnish your hard Jnat and never touch that surface with a nagura again?

    Besides, when you think about it your Jnat will typically be polished according to the nagura you're using in concert with it. Mine stays polished to somewhere in the 4 to 6k range, and that's well beyond what most do to their Arkansas stones.
    Steve56 likes this.

  4. #4
    Member
    Join Date
    Jan 2019
    Location
    north florida
    Posts
    98
    Thanked: 9

    Default

    Ok thinking out loud....

    If you are finishing on said stone with water only then yes you may see some advantage to polished jnat.

    But I see where you are heading with this... burnish or polish with jnat........ a glazed stone is already “burnished”

    Is that hard jnat not producing laser sharp edges, or satisfactory edges as it is?

    It can’t hurt to test it. A lapping session really won’t take any years off a hard jnat. Plus I understand you have quite the collection.

    I like that you are thinking outside of the box!!!
    Steve56 likes this.

  5. #5
    www.edge-dynamics.com JOB15's Avatar
    Join Date
    Feb 2013
    Location
    London
    Posts
    2,309
    Thanked: 372

    Default

    In my mind:
    To an extent yes. (maybe)
    The edges off a freshly lapped and somewhat smoothed hard jnat might not be as good as the edges off that same jnat if it had been used for a few months and formed a sheen.
    I think that is true or it could be a figment of my imagination.
    www.edge-dynamics.com

  6. #6
    Senior Member
    Join Date
    May 2014
    Location
    Knoxville, TN
    Posts
    1,346
    Thanked: 415

    Default

    Quote Originally Posted by JOB15 View Post

    ...

    I think that is true or it could be a figment of my imagination.
    That’s about where I’m at!
    JOB15 likes this.
    My doorstop is a Nakayama

  7. #7
    www.edge-dynamics.com JOB15's Avatar
    Join Date
    Feb 2013
    Location
    London
    Posts
    2,309
    Thanked: 372

    Default

    The problem is that there are too many variations leading up to a Jnat.

    The bevel set for one can make a massive difference to the end result. Then ontop of that you have what you feel or think or maybe know because some one told you.

    I think that stones have spirits and it more to do with that
    www.edge-dynamics.com

  8. #8
    Senior Member
    Join Date
    May 2014
    Location
    Knoxville, TN
    Posts
    1,346
    Thanked: 415

    Default

    It’s also good if the honer has some spirits...
    My doorstop is a Nakayama

  9. #9
    The Great & Powerful Oz onimaru55's Avatar
    Join Date
    May 2008
    Location
    Beau Dallah, South Coast
    Posts
    15,123
    Thanked: 3652

    Default

    Quote Originally Posted by Steve56 View Post

    But I have some jnats that are really, really hard. Not Ark hard of course, but with a tomo of equal hardness it will take 3 minutes or so to raise a light slurry with moderate to heavy pressure. They glaze to some extent, like an Ark maybe. I can de-glaze the stone (and nagura) and it works faster, but does a hard, glazed, jnat act finer like a hard burnished/glazed Ark? I think maybe a glazed hard jnat does finish finer than an unglazed one, but thought that I’d throw out this question for the jnat folks. Oz, Stefan?
    So if we're talking uber hard Jnats, like things that barely slurry with a diamond plate then I can't tell any difference in the final result. Such stones can be very slow cutting or sometimes "scratchy" so a bit of slurry can be a benefit. Even with scratches from an Atoma 1200 these stones will still reflect an image so it's kinda splitting hairs to me.

    I think you have an apples to oranges thing when you talk Arks & Jnats but no one says you can't purpose a stone the way you wanna.
    Euclid440, evnpar and Marshal like this.
    It ain't what you don't know that gets you into trouble. It's what you know for sure that ain't so..

  10. #10
    Senior Member blabbermouth
    Join Date
    Dec 2014
    Location
    Virginia, USA
    Posts
    2,209
    Thanked: 479

    Default

    Quote Originally Posted by JOB15 View Post
    In my mind:
    To an extent yes. (maybe)
    The edges off a freshly lapped and somewhat smoothed hard jnat might not be as good as the edges off that same jnat if it had been used for a few months and formed a sheen.
    I think that is true or it could be a figment of my imagination.
    In general this has been my experience as well. Whether we're talking about an Arkansas stone, my PHIG, my Jnat, or one of the Welsh slates they do seem to perform better (slower perhaps, but polish better) when they've simply been used for a few months and not lapped constantly for fear of it getting out of flat. Needless to say, at this point with harder stones I lap less, and just let the hone be what it is. If they get out of flat then I'll worry about it. My diamond plates probably appreciate this too, the PHIG really wears those poor puppies out.
    JOB15 and Steve56 like this.

  11. The Following User Says Thank You to Marshal For This Useful Post:

    Steve56 (01-29-2020)

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •