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2000x Grit Specific Studies

Recent Forums Main Forum Techniques and Sharpening Strategies Abrasives 2000x Grit Specific Studies

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  • #6026
    wickededge
    Keymaster
    • Topics: 123
    • Replies: 2936

    To kick off this thread, I polished the sample down to .25um with the kangaroo strops. The plan here is to develop a clean baseline from which to the lay in the scratches from a specific stone or strop so that we can isolate the scratches of that abrasive and not worry that we’re seeing leftover scratches from a previous abrasive. I didn’t go for total perfection in the polish since it’s time consuming enough that doing it for each and every grit we have available would be prohibitive. At this level, we have a clean enough slate that it will work very well for our purposes. I’ve imaged the blade at 200x, 800x and 2000x. The bevel is slightly curved since I was working from a blade that already had a micro-bevel. The shoulder of this edge is at 20 degrees and the edge is at 25 degrees. To study the different abrasives, I’ll work at 25 degrees so that we have a smooth shoulder to compare against and should be able to see the entire mirco-bevel in the field of view. Here are the images:

    200x:

    800x

    2000x

    -Clay

    #6091
    Anthony Yan
    Participant
    • Topics: 4
    • Replies: 96

    Hi Clay,

    Wow! I’m fascinated by these photos. 🙂

    In particular, I’m quite curious about what look like comets in your photos…. Dark spots with tails on them. I marked some on one of your photos:

    Any idea what these are?

    Sincerely,
    –Lagrangian

    #6095
    wickededge
    Keymaster
    • Topics: 123
    • Replies: 2936

    I see these a lot when I go to a higher polish. I think they are either inclusions getting pulled free or little pockets in the metal. Because there is a tail, I speculate that they are inclusions that dig a little furrow as they’re ripped out and pushed along the bevel toward the edge.

    Hi Clay,

    Wow! I’m fascinated by these photos. 🙂

    In particular, I’m quite curious about what look like comets in your photos…. Dark spots with tails on them. I marked some on one of your photos:

    Any idea what these are?

    Sincerely,
    –Lagrangian

    -Clay

    #6108
    Anthony Yan
    Participant
    • Topics: 4
    • Replies: 96

    I see these a lot when I go to a higher polish. I think they are either inclusions getting pulled free or little pockets in the metal. Because there is a tail, I speculate that they are inclusions that dig a little furrow as they’re ripped out and pushed along the bevel toward the edge.

    Wow…. pretty interesting. 🙂 Would be neat to get an idea of how big those inclusions are, especially the ones that tear out, and their relative size to grit ratings.

    I wonder what the inclusions are actually made of. Are they carbides, or slag impurities? Maybe someday, we can track down an metallurgist and ask.

    btw, have you ever considered doing a metallographic etch of metal for your microscope samples? Hmm… maybe not a good idea after all, since some of those chemicals are pretty toxic…

    Sincerely,
    –Lagrangian

    #6119
    Phil Pasteur
    Participant
    • Topics: 10
    • Replies: 943

    This should be good Clay!
    I can’t wait to see how the different grits look over the baseline finish.

    I can’t see why you would want to do any etching in this test series. I do understand why it is done in certain situations (detecting grain size and shape, inclusions, etc.), but I would think that it could possibly mask some of the results that you are trying to capture. I would guess that we should get great information about the scratch patterns without any etching.

    Phil

    #6135
    Anthony Yan
    Participant
    • Topics: 4
    • Replies: 96

    Hi PhilipPasteur,

    Oh, I didn’t mean specifically for this test. Possibly a bad idea to etch for these tests, since we’re interested in how the abrasive affects the surface, and don’t want that confused with how the etching could affect it.

    I was wondering etching might be useful in other ways. Maybe? Not sure. 🙂

    Sincerely,
    –Lagrangian

    #6141
    cbwx34
    Participant
    • Topics: 57
    • Replies: 1505

    I was wondering etching might be useful in other ways. Maybe? Not sure. 🙂

    I know there’s occassional discussions about “carbide tearout” in sharpening. Maybe a reason?

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