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almost super sharp..not quite..i need to get there

Discussion in 'Maintenance, Tinkering & Embellishment' started by steeltowninwv, Feb 2, 2015.

  1. IXLR8

    IXLR8

    98
    Feb 1, 2009
    The problem was defined by both Kyledf and myself within minutes.
    Yes I know you think you're the greatest knife sharpener since.........wicked edge.
    But in this case you have no clue what youre talking about.

    We're not talking about chisels or chiseled edged.
    We're talking about uniformity.
     
  2. singularity35

    singularity35

    Mar 1, 2010
    You're saying that the problem is an asymmetrical bevel which for all intents and purposes performs similarly to a chisel edge. The problem that the OP has has been a common problem here and it's always a burr. When I started sharpening I came across that problem often and it was always a burr. Not to do the low post count thing, but I don't think you've been here to see how often this problem comes up and it's always a burr.

    As Bgentry said, it's classic burr performance.

    As Bgentry says, the giveaway is that it shaves on one side.
     
  3. IXLR8

    IXLR8

    98
    Feb 1, 2009

    It is not a burr.
    We've been thru this already. The OP just , not 15 minutes ago said, " it's not a burr."
    I'm telling you with 100% certainty, that what he is describing is not a burr causing his problem.

    The burr is caused by sharpening one side.........achieving the burr on one side.
    Then filing the burr off for an approach to 0 degree.

    The op has been honing both sides.


    PS. don't let post count fool you.
     
  4. bgentry

    bgentry

    Aug 3, 2009
    Ask yourself this: Will an asymmetrical bevel shave on one side and not the other? In my experience no. A bevel with uneven widths will shave on both sides equally if it is properly apexed. A Yanigiba will POP hair off your arm on both sides. A really sharp chisel will do the same.

    I know your instinct might be telling you something different, but have you tested your assertion?

    PS: The sharpmaker can produce a burr on one side and not the other, even when using equal numbers of passes per side. It depends on the condition of the edge when it starts.

    Brian.
     
  5. steeltowninwv

    steeltowninwv

    201
    Jan 1, 2015
    oh boy im confused...if its a burr..i cant seem to get it to disappear....I moved to the left side of the sharpmaker and made 15 strokes then like 3 on the right side....still the same....
     
  6. steeltowninwv

    steeltowninwv

    201
    Jan 1, 2015
    there is no doubt this knife is sharp...cuts phone book paper cleanly..i just seem to have to try and master everything I start...so hand sharpening will be later on..but I gotta get this first
     
  7. singularity35

    singularity35

    Mar 1, 2010
    I'm thinking that you have an asymetrical bevel but that is not the cause of the uneven sharpness. The asymetrical bevel is causing the sharpmaker to hit the edge on one side only and that it's causing a burr that can't be removed by stroking on the other side because the other side of the bevel is not hitting the edge. You are basically hitting the shoulder on the bevel on the side of the knife that seems sharper to you.

    A quick fix is using the sharpie trick. Color the bevels with a sharpie and go back to the sharpmaker. After a couple dozen strokes, look at the bevels again, preferably with magnification. You'll be able to see what part of the bevel on each side the stone is hitting.

    After you see which side of the bevel is not being hit to the edge, then while you stroke the side(whose bevel is not being hit all the way to the edge) of the knife, tilt the spine away from the stone in sufficient angle that the stone will hit the edge of the bevel.

    One more thing, burrs often need an educated finger to feel. A good way to test for a burr is to wipe a cotton ball on the bevel in a spine to edge direction. If it catches, then there's a burr.

    It is nevertheless not the asymetrical bevel that is causing the unequal performance between sides but it is the asymetrical bevel combined with the fixed angles of the sharpmaker that is causing the burr that is causing the erratic performance.
     
  8. IXLR8

    IXLR8

    98
    Feb 1, 2009
    It's not a burr.

    Now the other thing you may not be taking into account is the shaving aspect of all this. AND NONE OF US THOUGHT ABOUT THIS
    When you shave a hair in the direction the hair is laying naturally, it will shave better. Once you flip the knife and shave against the direction the hair is laying......it should still shave, but not as efficiently. So before this goes any further...........switch hands and shave both arms in the direction the hair is laying.
    If it shaves one arm more cleanly than the other, or you have to make more passes to achieve the same result as the opposite arm.........you have an edge geometry problem.
     
    Last edited: Feb 3, 2015
  9. Jamesh Bond

    Jamesh Bond

    Jan 14, 2007
    Then what is a wire edge?
     
  10. IXLR8

    IXLR8

    98
    Feb 1, 2009
    Is this some kinda test?
     
  11. Jamesh Bond

    Jamesh Bond

    Jan 14, 2007
    Its a question.

    I see them form often on blades sharpened on alternating sides.
     
  12. Trabireiter

    Trabireiter

    57
    Mar 10, 2008
    I think this is spot on. Especially for knives with thicker blades (and grinds) this can happen much more often than one might think.

    The sharpmaker is a great tool if you start with a 20/20° knife or initially spend the time to set the primary bevel on the sharpmaker until it's apexed all the way. If the Knive is not 20/20 (or below) there will be inconsistent results or the user will have to compensate the angle by hand.
     
  13. singularity35

    singularity35

    Mar 1, 2010
    You may not have thought of it but most of us have. When the OP shifts sides, then he's shaving his other arm in the same direction as when he used his other hand to shave his other arm.

    But granting that what you are saying is correct, then it should follow that if the lay of the hair is the problem, then even knives with even bevels will have a problem going both ways. If you're right then the OP doesn't really have a problem except that his armhair is lying in a certain direction.

    What you really can't seem to understand is that the bevel angles don't matter when you shave armhair, what matters is how cleanly the apex is finished.

    I'm almost tempted to sharpen a knife with different angles for each side and show you that it can shave armhair easily as long as the apex is well shaped.
     
    Last edited: Feb 3, 2015
  14. singularity35

    singularity35

    Mar 1, 2010
    Video of a Richard J convex chisel shaving armhair on both sides inspite of asymetrical grind.

    [video=youtube;E7cFQQMY-4Y]https://www.youtube.com/watch?v=E7cFQQMY-4Y[/video]
     
  15. Jason B.

    Jason B. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 13, 2007

    You should stop posting and start reading before you give any more bad information.
     

  16. That's classic burr behavior, with the burr leaning to one side; a very common symptom of burring, and even likely most of the time. When the edge is apexed, and the burr forms, it'll almost immediately be curled or folded away from the side being honed. When shaving successfully on your arm, the burr is leaning down into the hair/skin, and it's able to pinch the hair against the skin and clip it away. It struggles from the other side, because the burr leans or 'curls' up & away from the hair/skin, so the flat of the edge (really, the flat of the burr, not the edge) just slides over the hair.

    BIG burrs can usually be felt with a fingernail, or similar means. But finer/smaller burrs will always be revealed in how the edge behaves when cutting, even if they're otherwise too small to catch a nail or be felt with the fingertips. That's the value in testing shaving from both sides of the blade, as you've done.


    David
     
    Last edited: Feb 3, 2015
  17. The hardness of the ceramics on the SM will exacerbate burring issues, when burrs are otherwise prone to show up in the first place. Some very ductile steels are more prone to it than others, and it's all too easy to create burrs or exaggerate existing ones on hard ceramics.

    A number of things you can do:

    • Decrease pressure on the rods. Pressure makes burrs bigger, or helps create them. Too much pressure on very hard hones (ceramics) magnifies the effects of pressure, and especially if honing on the edges/corners of the triangular rods, or on round rods, where the contact point is very small.
    • Strop with a material & compound that works well to remove burrs. My favorite is a denim strop with white rouge or a similar AlOx compound (even Flitz/Simichrome or Mother's Mag polish work well for this, on a hard-backed denim strop).
    • Some burrs can be stropped away using plain paper over a hard backing, like a sharpening stone. Still need to be careful with pressure, when doing it this way, because it's still easy to create burrs or otherwise fold the edge on very ductile or softish steels, because the backing under the paper is still very hard.


    David
     
    Last edited: Feb 3, 2015
  18. IXLR8

    IXLR8

    98
    Feb 1, 2009
    I want you to show me where I ever said that a chisel grind could not shave hair.

    I watched your video and I know you posted it attempt to humiliate, but at the same time trying to teach.
    Well done.
    It appears to me that the cut angle changed from one arm to the other. In other words a steeper cut angle on the right arm.
    Though I agree with you that the op's apex is not finished properly, i still do not think this is what he was looking for.
    I could be wrong. Nothing wrong with being wrong, I do it all the time.
    You should have flipped the knife on the same arm on the video. I think that's what the OP is doing.
    Cut angle on left arm: [​IMG]

    cut angle on right arm: [​IMG]
     
  19. IXLR8

    IXLR8

    98
    Feb 1, 2009
    People like you are the reason I don't post here much.
     
  20. chiral.grolim

    chiral.grolim Universal Kydex Sheath Extension Knifemaker / Craftsman / Service Provider

    Dec 2, 2008
    Hmm... That seems exactly the opposite from my experience both in shaving and in cutting grass/hay with a scythe-blade (similar practice). When the burr leans down, it does NOT "pinch" at all, rather the side of the bevel pushes the hair (or grass) away unless you use a LOT of pressure and scrape the skin (dirt) in your effort. It does this regardless of the angle of approach, and raising the angle only makes it worse. In contrast, with the burr curving up the edge can catch and cut the hair (grass) quite effectively, though it will tug if not well finished so as to complete the cut with minimal effort. If you raise the angle of approach, the burr-apex points more directly perpendicular to the stems which can actually be less effective as an angled cut penetrates more easily.

    Burr down = no cut. Burr up = cut.
     

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