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Thread: Objectifying edge quality

  1. #16
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    Quote Originally Posted by bridger berdel View Post
    one should always endeavor to keep ones edges as sharp as possible, but no sharper.
    Absolute genius. I need to have these words engraved on a brass plaque and mount it over my little shops door. Seriously.

    I also like what James wrote: "Sharp is as sharp does." That summarizes the law and the prophets.

    Sharpness is very like a Zen koan. Something very close to nothing.

    The test I use is quick and subjective, but reliable. Similar to Prashun's method, I cut the callous on the side of my left index finger just a tiny bit. Not enough to touch any nerves or cause leakage, but enough tell without a doubt how well the blade cuts comparatively.

    I hold the blade in my right hand and choke up on it, and rest the blade on my left index finger while moving the callous lightly against the blade. This way the blade is tightly controlled and there is no risk of cutting too deeply.

    The fingernail check is almost, but not quite, as informative. In my experience.
    Last edited by Stanley Covington; 10-18-2017 at 8:17 PM.

  2. #17
    Is the tool cutting well? Work. Not cutting well? Sharpen.

    That's about all the 'contemplation of the infinite' I have time for these days ;-)

  3. #18
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    The feeling w the fingerpad sounds like a great way-I shall try that.

    There are lots of other variables, right?

    How well does the edge hold up, what about microfractures, angle of bevel, etc.

    David W talks about A2 doing better w a microbevel on account of microfracture.

    All my stuff is A2-right now, that is good.

    My thinking in the past was that a picture showing less grooves in the edge, and less 'trash' there would be better. To a point, yes.

    When I did freehand, and put a camera on it, all my grooves were parallel to the edge. I am not sure if that is an advantage or not

    So, now, in the rabbit hole of sharpness, have temporarily gone back to jigs.

    Plus, I discovered last weekend that my plane blades can be swiped/honed w/o removing the chipbreaker-Excellent.

    Do some of you just keep honing that way, only breaking it down for a formal session when necessary (it becomes obvious the edge geometry is fouled)?

    And, as tempting as it is to have some cool equipment around, am currently resisting spending more money; the force gages look great. The minimum resolution on the HF-50N is 0.45g ($148). I think after a while I would have buyers remorse - I hate that.

    Have some diamond submicron sheets coming in to use w the other LV 0.5 micron that I started w last weekend.

    I don't feel like delving into the O1 and PMV11 rabbit hole.

    We are talking about planes and would here.

    You know, I guess this entire side track allows me to put off make those stopped dadoes in the near-finished Cherry project.

    Thanks guys, I am reading (more than once) and digesting all your input
    David
    Confidence: That feeling you get before fully understanding a situation (Anonymous)

  4. #19
    If I strop dry I may not remove the breaker. But if I take it to a water stone I find it is easy to get rust if the blade is not dried properly. Disassembling the blade helps the drying.

  5. #20
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    The most important things are to have good geometry and remove the burr entirely. I do this by having a flat back and bevel and maintaining them by removing the wear every time I sharpen.
    Bumbling forward into the unknown.

  6. #21
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    The true gauge of sharpness is how much work you get done between sharpening's. This is the same as sharp enough but no sharper as the too sharp is wasted on the first cut. Finish planing gives less work between sharpening's, simple really!
    ​You can do a lot with very little! You can do a little more with a lot!

  7. #22
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    Quote Originally Posted by Prashun Patel View Post
    If I strop dry I may not remove the breaker. But if I take it to a water stone I find it is easy to get rust if the blade is not dried properly. Disassembling the blade helps the drying.
    Thanks for that reminder. Those LV blade screwdrivers do a great job of loosening.


    Quote Originally Posted by Brian Holcombe View Post
    The most important things are to have good geometry and remove the burr entirely. I do this by having a flat back and bevel and maintaining them by removing the wear every time I sharpen.
    How wide a strip are we talking about w the wear bevel? Not questioning it's importance to remove.....just never considered it.


    Quote Originally Posted by William Fretwell View Post
    The true gauge of sharpness is how much work you get done between sharpening's. This is the same as sharp enough but no sharper as the too sharp is wasted on the first cut. Finish planing gives less work between sharpening's, simple really!
    This is precisely what is in the back on my mind. Once you have a proper bevel, or microbevel, and the grooves/striations in blade from the abrasive are acceptably small......all those obsession is gone after a couple of strokes?
    David
    Confidence: That feeling you get before fully understanding a situation (Anonymous)

  8. #23
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    The wear bevel is very small. I haven't measured but perhaps a thou or two? Maybe smaller than that. You can see it as a strip on the back of the blade, right at the edge. You just keep working the bevel until it is gone. It's usually not too much work unless the blade is pretty far gone. The important point is to realize that you can raise a burr from working on the bevel side without having completely removed the wear bevel. Typical sharpening advice would have you stop once you raise the burr, but you should check if the wear bevel remains. If it does then keep working.

    You can get a decent edge without totally removing the wear bevel, but the edge quality and endurance seem significantly improved if you do. Within certain limits, I would say it has a bigger effect than the typical sharpening obsessions like grit size, type of stone, number of microbevels, etc.

  9. #24
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    Quote Originally Posted by Robert Hazelwood View Post
    The wear bevel is very small. I haven't measured but perhaps a thou or two? Maybe smaller than that. You can see it as a strip on the back of the blade, right at the edge. You just keep working the bevel until it is gone. It's usually not too much work unless the blade is pretty far gone. The important point is to realize that you can raise a burr from working on the bevel side without having completely removed the wear bevel. Typical sharpening advice would have you stop once you raise the burr, but you should check if the wear bevel remains. If it does then keep working.

    You can get a decent edge without totally removing the wear bevel, but the edge quality and endurance seem significantly improved if you do. Within certain limits, I would say it has a bigger effect than the typical sharpening obsessions like grit size, type of stone, number of microbevels, etc.
    +1 on this. To me not removing the wear bevel means the job isn't finished. The wear bevel may seem akin to the "ruler trick" to some when sharpening a blade, it isn't. It is metal deformed by wear, not by strategy.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  10. #25
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    Quote Originally Posted by Robert Hazelwood View Post
    The wear bevel is very small. I haven't measured but perhaps a thou or two? Maybe smaller than that. You can see it as a strip on the back of the blade, right at the edge. You just keep working the bevel until it is gone. It's usually not too much work unless the blade is pretty far gone. The important point is to realize that you can raise a burr from working on the bevel side without having completely removed the wear bevel. Typical sharpening advice would have you stop once you raise the burr, but you should check if the wear bevel remains. If it does then keep working.

    You can get a decent edge without totally removing the wear bevel, but the edge quality and endurance seem significantly improved if you do. Within certain limits, I would say it has a bigger effect than the typical sharpening obsessions like grit size, type of stone, number of microbevels, etc.
    Quote Originally Posted by Jim Koepke View Post
    +1 on this. To me not removing the wear bevel means the job isn't finished. The wear bevel may seem akin to the "ruler trick" to some when sharpening a blade, it isn't. It is metal deformed by wear, not by strategy.

    jtk
    This is most excellent getting down to what I had not appreciated.

    So, the 0.001" wear bevel that might be visible via close inspection (w magnification)......and, I am not being sarcastic here.........I will try some swiping the back of the blade on honing media, and just look at it again to be sure the wear bevel is gone? that simple?
    David
    Confidence: That feeling you get before fully understanding a situation (Anonymous)

  11. #26
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    Quote Originally Posted by David Ragan View Post
    This is most excellent getting down to what I had not appreciated.

    So, the 0.001" wear bevel that might be visible via close inspection (w magnification)......and, I am not being sarcastic here.........I will try some swiping the back of the blade on honing media, and just look at it again to be sure the wear bevel is gone? that simple?
    I don't think you need magnification. Maybe reading glasses if your eyes aren't so good. Try using a plane until it won't take a good shaving anymore, then remove the blade and chipbreaker and see if you can find the wear bevel. It should be readily visible, right at the very edge.

    You can remove the wear bevel by working the back, but it makes more sense to me to work it from the bevel side. I don't like to do anything to the backs except work them on the finishing stone to remove the burr. You would probably have to go to a coarser stone to remove the wear bevel by working the back, then polish that back out on the finishing stone. Instead, you can work the bevel on your coarse stone, until the edge has moved back far enough that the wear bevel is gone. In other words you are making the blade a tiny bit shorter, until the new edge intersects the unworn portion of the back. Then just refine the scratch pattern to your liking and remove the burr.

  12. #27
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    Quote Originally Posted by Robert Hazelwood View Post
    You can remove the wear bevel by working the back, but it makes more sense to me to work it from the bevel side.
    This is exactly what occurred to me after the response.

    Makes complete sense.

    Not much is said about the wear bevel cause we remove them in the normal course of sharpening usually.
    Last edited by Prashun Patel; 10-20-2017 at 4:13 PM.
    David
    Confidence: That feeling you get before fully understanding a situation (Anonymous)

  13. #28
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    Quote Originally Posted by David Ragan View Post
    Not much is said about the wear bevel cause we remove them in the normal course of sharpening usually.
    Ideally, yes. But if you find yourself wondering why the edge you just sharpened doesn't feel quite as sharp as it should, or doesn't last as long as you expect, this is a likely culprit.

    By the way, and getting back to the original intent of this thread, I like what Stanley posted about testing the edge against the fingertip callouses. It's what I do and you can really tell a lot from it. It just takes repetition and experience to develop the feel.
    Last edited by Robert Hazelwood; 10-20-2017 at 7:01 PM.

  14. #29
    Andrew

    Thanks for this tip. I had not heard of edgeonup. I had seen Steve Ellis thread test, which is the basis of edgeonup. I got inspired and today I made a thread tester out of sewing thread and a piece of UHMW plastic. I "calibrated" it by finding a weight for the thread that would almost but not quite allow the thread to flex without being cut by a new single-edge razor blade. Maybe you can satisfy your engineering impulses by making one for yourself. If you do, let me know how you make out.

    I will run out of arm hair or calluses long before I run out of thread.

    Doug

  15. #30
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    Quote Originally Posted by Doug Hepler View Post
    Andrew

    Thanks for this tip. I had not heard of edgeonup. I had seen Steve Ellis thread test, which is the basis of edgeonup. I got inspired and today I made a thread tester out of sewing thread and a piece of UHMW plastic. I "calibrated" it by finding a weight for the thread that would almost but not quite allow the thread to flex without being cut by a new single-edge razor blade. Maybe you can satisfy your engineering impulses by making one for yourself. If you do, let me know how you make out.

    I will run out of arm hair or calluses long before I run out of thread.

    Doug
    You made yourself a tension scale out of a cantilever beam. The only thing to be careful of there is to increase pressure slowly, as (obviously) it isn't peak-reading the way the EdgeOnUp device or a commercial tension gauge would be.

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