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Thread: More on Unicorn Profile

  1. #46
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    To repeat what Derek and a couple of others have said. The initial testing by David Weaver, and then confirmed by others, revealed that the 1000 grit grinding- cotton wheel buffing technique resulted in a longer lasting edge in mortising chisels. It also revealed that inexpensive, lesser quality chisels could be made to perform as well as more expensive ($75 - $100 ea) chisels. For some of the earlier explorers of the technique, the potential for the use of less expensive chisels for chopping was probably the first gain noted by the use of the technique. At this time, the technique is more about a much shorter sharpening time plus a longer lasting edge rather than creating a higher level of sharpness. I think David started somewhere back in the experiment by counting the number of "chops" it took to accomplish a defined length of "chopped" material with different chisels or something like that, and the technique has evolved as others are jumping in to help test different paths the experiment is taking. Photos of chisel tips before/after sharpening/buffing and "chopping" have been provided for folks to see what is taking place. The time saving of having a (as David suggests) machine ground 20* bevel (that lasts through several following individual sharpening sessions), then hand sharpening a micro bevel at the tip of the chisel with a 1000# stone and finishing up by polishing with a buffer for 5-20 sec. is probably much quicker than many of us are doing now. The initial machine grinding (at whatever bevel angle) does not need to be done every time.
    David

  2. #47
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    Quote Originally Posted by David Eisenhauer View Post
    To repeat what Derek and a couple of others have said. The initial testing by David Weaver, and then confirmed by others, revealed that the 1000 grit grinding- cotton wheel buffing technique resulted in a longer lasting edge in mortising chisels. It also revealed that inexpensive, lesser quality chisels could be made to perform as well as more expensive ($75 - $100 ea) chisels. For some of the earlier explorers of the technique, the potential for the use of less expensive chisels for chopping was probably the first gain noted by the use of the technique. At this time, the technique is more about a much shorter sharpening time plus a longer lasting edge rather than creating a higher level of sharpness. I think David started somewhere back in the experiment by counting the number of "chops" it took to accomplish a defined length of "chopped" material with different chisels or something like that, and the technique has evolved as others are jumping in to help test different paths the experiment is taking. Photos of chisel tips before/after sharpening/buffing and "chopping" have been provided for folks to see what is taking place. The time saving of having a (as David suggests) machine ground 20* bevel (that lasts through several following individual sharpening sessions), then hand sharpening a micro bevel at the tip of the chisel with a 1000# stone and finishing up by polishing with a buffer for 5-20 sec. is probably much quicker than many of us are doing now. The initial machine grinding (at whatever bevel angle) does not need to be done every time.
    David,

    And cheaper . Not so much using cheaper chisels but the thousands of dollars in stones that may no longer be needed or used.

    Thanks, a good summery of where we are.

    ken
    Last edited by ken hatch; 08-13-2020 at 11:26 PM.

  3. #48
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    Quote Originally Posted by David Eisenhauer View Post
    To repeat what Derek and a couple of others have said. The initial testing by David Weaver, and then confirmed by others, revealed that the 1000 grit grinding- cotton wheel buffing technique resulted in a longer lasting edge in mortising chisels. It also revealed that inexpensive, lesser quality chisels could be made to perform as well as more expensive ($75 - $100 ea) chisels.
    This is still my question(s). Lesser quality chisels performing as well as more premium chisels... meaning premium chisels sharpened just on stones (no unicorn buffing)? What happens to a premium chisel with the unicorn buff? Exact same as chepo chisel? Or equally x-fold better than traditionally/stone sharpened?

    Stated another way, are cheapo chisels unicorned exactly the same as a PM-V11 chisel unicorned?

  4. #49
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    Hi Erich,

    Winston and David (in videos and other forums) showed clearly I think that an unicorned inexpensive chisel would perform at least as well as more expensive brands that were also unicorned. From my own modest experiments, I took some cheap chisels that I could never really finesse an edge onto and tested them with the unicorn edge. I was impressed. Winston, David, and many others have reported similar results. The buffed edge holds up extremely well especially for chopping. I didnít not notice any real drop in performance going through oak or poplar.

  5. #50
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    Quote Originally Posted by Erich Weidner View Post
    This is still my question(s). Lesser quality chisels performing as well as more premium chisels... meaning premium chisels sharpened just on stones (no unicorn buffing)? What happens to a premium chisel with the unicorn buff? Exact same as chepo chisel? Or equally x-fold better than traditionally/stone sharpened?

    Stated another way, are cheapo chisels unicorned exactly the same as a PM-V11 chisel unicorned?
    Erich, I would venture that the law of diminishing returns applies. That is, the benefits of the unicorn profile is best observed on a cheap or poorer edge-holding blade, with less benefits seen in the premium blade. I posted early on my success in buffing a 20 degree bevel on a set of boxwood Marples. These are wonderfully light in the hand, but held an edge for exactly 1.5 shavings. Post-buffing, the edge was excellent. I was not looking to see exactly how long, but there were very significant gains. I have not attempted to buff Veritas to the unicorn profile (largely because the edge-holding is excellent anyway), but have buffed to hone a dulling edge, and that did leave a superior sharpness.

    Regards from Perth

    Derek

  6. #51
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    There is a David W video on You Tube that shows him sharpening and buffing a Sorby chisel. The actual work starts after the :31 min mark when he sharpens a chisel on a stone then buffs it afterwards. I did not watch the entire video (just fast forwarded to a sharpening sequence) or listen to any of the video (due to some dewatering fans roaring away in my house to get rid of a plumbing leak moisture), but from reading lots of the discussion of the technique, this must be what the discussion is about.

    Erich, from what I remember reading (lots and lots of discussion to wade through) your question was asked during the earlier stages of the buffing experimentation. I think what I read was that the PM 11 stuff had not yet been tested yet, but it was believed that the PM 11 chisel would continue to be a superior chisel, albeit perhaps not quite as head and shoulders above the cheaper models as before. If you need a definitive answer, please don't count on my memory, as there was (is) lots and lots of stuff to review over several discussions. Perhaps Winston, Derek or others will respond.

    https://www.youtube.com/watch?v=Do7FdOh6S9s
    David

  7. #52
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    Quote Originally Posted by Tim Best View Post
    Hi Erich,

    Winston and David (in videos and other forums) showed clearly I think that an unicorned inexpensive chisel would perform at least as well as more expensive brands that were also unicorned.
    So, the conclusion is that more expensive brands/better steels are now obsolete as cheap chisels with relatively garbage steel unicorned perform just as well as premium chisels?

    I'm not trying to be snarky, but my soul hurts somehow... Also, it just doesn't make sense to me. If the steel doesn't hold an edge as well with traditional sharpening, why would it hold an edge better with the unicorn buff (vs. better steel)? I have no education in metallurgy, so I might just be wasting folks time. I'd love to see something like Derek's dovetail durability testing I read on his site with unicorned stuff vs. not.

    Edit: At least two other responses appeared while I was typing the above masterwork post. So, sorry if this post is out of date.
    Last edited by Erich Weidner; 08-15-2020 at 12:49 AM.

  8. #53
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    Quote Originally Posted by Erich Weidner View Post
    This is still my question(s). Lesser quality chisels performing as well as more premium chisels... meaning premium chisels sharpened just on stones (no unicorn buffing)? What happens to a premium chisel with the unicorn buff? Exact same as chepo chisel? Or equally x-fold better than traditionally/stone sharpened?

    Stated another way, are cheapo chisels unicorned exactly the same as a PM-V11 chisel unicorned?
    Derek's diminishing returns summarizes what I understood David Weaver to say about his tests. PM-V11 improved, some, with the Unicorn treatment. Cheapie improved, a lot, with the Unicorn treatment. But it only narrowed the gap, PM-V11 was still better than the cheapie. Note the PM-V11 doesn't grind, hone, or buff as quickly so YMMV for overall efficiency depending on your usage.

  9. #54
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    The thinking is that the buffing technique reshapes the geometry (creates a very, very tiny 45* micro bevel?) at the very tip edge of the chisel so that the factors that cause a lesser quality steel chisel to fold quicker than a chisel with better steel are mitigated sufficiently to show a marked improvement in the lesser quality steel chisel's performance. David W did some chopping tests at the beginning of the experiment to establish some base lines and you may wish to review that for more info.
    David

  10. #55
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    So, the conclusion is that more expensive brands/better steels are now obsolete as cheap chisels with relatively garbage steel unicorned perform just as well as premium chisels?

    ... Also, it just doesn't make sense to me. If the steel doesn't hold an edge as well with traditional sharpening, why would it hold an edge better with the unicorn buff (vs. better steel)?
    The thinking is that the buffing technique reshapes the geometry (creates a very, very tiny 45* micro bevel?) at the very tip edge of the chisel so that the factors that cause a lesser quality steel chisel to fold quicker than a chisel with better steel are mitigated sufficiently to show a marked improvement in the lesser quality steel chisel's performance.
    The close up image of the unicorn edge showed smooth steel. Before that the edge was very rough with the lines from the abrasive. These little fissures may be fracture inducing as the edge does its work. A slight increase in the edge angel (added micro bevel) may also be adding to the edge's longevity.

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

  11. #56
    Quote Originally Posted by Erich Weidner View Post
    This is still my question(s). Lesser quality chisels performing as well as more premium chisels... meaning premium chisels sharpened just on stones (no unicorn buffing)? What happens to a premium chisel with the unicorn buff? Exact same as chepo chisel? Or equally x-fold better than traditionally/stone sharpened?

    Stated another way, are cheapo chisels unicorned exactly the same as a PM-V11 chisel unicorned?
    I think I answered this elsewhere on the forum, but I tested both the Buck Bros and Veritas PM-V11 chisels, each of them flat-honed and buffed. (In my video, I didn't do the buffed PM-V11 chisel.) The results are here:
    https://chisel-test.netlify.app/

    Short version: the buffed Buck Bros and Veritas chisels both had essentially no visible damage at the end of the test, in which they chopped off 20 1/16"-thick slices of a piece of maple. In both cases, even though they looked undamaged, the chisels felt slightly less sharp at the end. I didn't do any more chopping with the chisels -- I felt that I'd have to do a LOT more chopping to see any visible damage, and it didn't seem worth it.

    I'm not a metallurgist, but I suspect that the buffed Veritas wouldn't hold up a huge amount longer than the Buck Bros chisel. For both of them, the chopping is not exerting enough force on the metal to cause any folding or chipping (at a scale visible with the microscope), and so I suspect that the only cause of dulling would be abrasion. PM-V11 probably has better abrasion resistance than whatever inexpensive steel is used in the Buck Bros, but I doubt it would hold up, say, 3x longer. This is just speculation, though.

    For me personally, I no longer feel the need to search for chisels with super steel. It's hard for me to justify spending another $100 on a Veritas chisel.

    I should mention, though, that buffing won't turn junk chisels into gems. Out of curiosity, I got a set of very cheap chrome-manganese chisels on Amazon (4 for $10) that look like the Aldi chisels, and they were way too soft. Even with buffing, the edge had significant visible damage after paring about 6" of pine end grain. The Buck Bros chisels are much, much better.

  12. #57
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    Thanks again, for all the contributions here and over at WC. Derek, my favorite Imai bench chisels came with about a 32 degree bevel and thatís pretty much where Iíve kept them. I do add 1-2 degree tiniest of tiny micro bevel (like 2-3 strokes) to make sure Iíve gotten right to the edge with the flat bevel. Iím sure a lot of folks could make my tools sharper.

    Funny, all this talk and tests brings me back to the first Windsor chair class I took over 20 years ago. It was from a crusty Vermont craftsman who worked in a barn. He had the rattiest tools, looked awful, and I showed up with my fancy stuff like a city boy (which Iím not). I still remember watching him work, how he moved, and when a tool wasnít working quite right, how quickly he would turn, touch to his buffer, and back to work. I remember him saying something like ďthe Ďexpertsí will tell you this messes up the geometry, but I donít have time for that talk...I know my tools cut and thatís whatís important when you make a living at this.Ē When his chisels got a little too far gone, he quickly hit the bevel on an old stone or even a piece a sandpaper right on his bench.

    Thanks again, I look forward to trying this out.

    Kevin

  13. #58
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    Kevin, I have owned a 10" Tormek for about 10 years. Probably have not used it in 5 years after moving to a CBN wheel. The Tormek's hard leather strop was the reason that Tormek refer to the machine as a "sharpening system". One is meant to go from a 220 grit wheel, to a refined wheel at 1000 grit, and then strop the bevel on the leather wheel, which is impregnated with compound. I could never get it to create an edge even remotely close to that off a fine waterstone.

    Today I was doing some work around the house. I have a couple of chisels handy for rough work. I grabbed one - 30 degree bevel and M4 steel (that is very tough stuff) - and held the bevel to the buffer, this time just with the intention of buffing the existing bevel face. It is quite easy to align the edge of the wheel with the bevel as mine are honed directly on a hollow grind. In about 5 seconds the edge was razor sharp. At speed, this forgiving, soft stitched linen strop leaves the slow, hard leather strop for dead.

    Regards from Perth

    Derek
    Last edited by Derek Cohen; 08-15-2020 at 9:50 AM.

  14. #59
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    Super interesting- thanks to all who posted. Does grinder speed matter? I have 3,650RPM do I need to get half speed version? What about grinding primary bevel angle to 20 degrees- optional or required?
    Thanks, Mike

  15. #60
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    Mike, grinder speed does matter. Ultimately it is a balance between speed, the hardness/softness of the buffer, and the cutting level of the compound used. Add to this the amount of time the blade is held against the buffer ... and, of course, the angle. All this makes it sound complicated, but it is not. It is something one sets up one time and adjusts to.

    Regards from Perth

    Derek

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