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  • Unicorn - a “new” sharpening method

    https://vimeo.com/444232624
    Les Groeller likes this.
    Measure twice, cut once ... and if that doesn't work try again
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  • #2

    Re: Unicorn - a “new” sharpening method

    There’s a lot of other videos and info on the Wood Central forum (David Weaver), but there should be an article that will summarize all the sharpening possibilities (variants, techniques for different tools) soon.

    The main advantages of using a buffer this way are the speed of sharping, low cost, and greatly improved edge durability (so going longer before sharpening). Highly recommended.
    Frank
    SPCHT

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    • #3

      Re: Unicorn - a “new” sharpening method

      I just wish I could sharpen my chisels so they were as straight across the cutting edge as his are...
      The older I get, the better I was.........

      Comment


      • #4

        Re: Unicorn - a “new” sharpening method

        I've been playing around with this the last few weeks. The video link is a touch different than how Weaver explains it and does it. Weaver seems to prefer hollow grind, and then free hand in a secondary bevel then buff. I don't think I can free had a consistent secondary bevel and I find jigs too slow, so I've just been grinding, sharpening that bevel, then buffing. So far my results have been pretty good. Its definitely faster than going through a bunch of stones and strops... I'm just using a cheap 6" bench grinder with a buffing wheel from princess auto. I had some nice buffing compound for carving knives, but frankly the cheap blue stuff from princess auto seems to perform just as well.

        again, I'm just starting to mess around with this, but I like the method quite a bit so far. Probably worth looking into IMO.
        Cheers,
        SPCHT

        Comment


        • #5

          Re: Unicorn - a “new” sharpening method

          It is just my opinion but I don't think that is a good way to sharpen anything other than carving tools since it rounds the edge significantly and even then it will remove sharp corners that you really want/need for the tool to be truly effective.  I have a pair of 3-M hard felt wheels charged with Veritas honing compound on a motor driven, double ended mandrel and did try using the set-up on a chisel once, just once!  It took significant effort to get the chisel back into usable shape afterwards since, while it was razor sharp, it was rounded everywhere you would not want it to be.  When I acquired Leonard Lee's book I "discovered" that he discouraged the practice for the aforementioned reason.  A buffing wheel is for polishing and it is absolutely indiscriminate as to where it removes metal.  I polish a lot of plastic, aluminium, brass and steel things that I make so have acquired a lot of buffing wheels and compounds over the years to doll them up proper.  I sometimes don't even bother to dis-burr things from the lathe and mill since I know that the buffing process will break the sharp edges quite nicely.

          I wonder about something since this comes up often as a topic; how often do folks actually redo the bevel on their chisel and plane irons?  I find that edge tools typically can be re-honed dozens of times before I have to back up from the strop/8000x stone to a 4000x stone and I might have to go back to a coarser stone a couple of times a year, usually only when I damage something.  To try to illustrate what I am driving at, I have one X-Acto #26 blade that I have been using since I bought it in Toronto in 1979 which has never seen anything coarser than a 4000x stone (for the uninitiated, X-Acto blades are not particularly hard steel but they do take a great edge, it just isn't a particularly durable edge).  Another example from my junk is that I have never reground the factory bevels on my Marples Blue Chip utility chisels (my learner set of 4) since they entered service back in 1983 save for the 1/8" one (added much later) as it was the victim of the felt wheel debacle mentioned earlier and needed a lot of work to re-lap, re-flatten and re-square before it would perform its intended function. 

          If you are going to use buffing wheels to try to sharpen your good edge tools, you might consider charging the wheels with Veritas green compound. It is a good investment and addition to the sharpening arsenal as a polishing compound for steel plus it makes a really good stropping compound too.

          I am not lecturing you all, just genuinely curious.  I know that the time expended to recover my narrowest chisel was an awful lot more than anything I might have saved by trying to hurry up the process. 

          Ken

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          • #6

            Re: Unicorn - a “new” sharpening method

            Hi Ken,
            if you look at the article (I can provide a link...not at my computer now), the use of a hard felt buffer is not recommended. It takes a soft stitched buffing wheel for this to work because the rounding does not affect geometry, or it does on such a microscopic level that the blade behave the same way it would with no buffing. Any visible rounded edge, never mind rounded corners, is too much.
            David Weaver and Winston as well as others over on Wood central have done a lot of trials with really good microscope pics.
            This really has nothing to do with using a buffer to put a shine on an edge.
            Frank
            SPCHT

            Comment

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            • #7

              Re: Unicorn - a “new” sharpening method

              The Unicorn method advocates the use of a soft cloth buffing wheel charged with buffing/stropping compound and addresses the use of a hard felt wheel as inappropriate for this method of sharpening for, I believe the reasons described above, I.e. being too aggressive.

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              • #8

                Re: Unicorn - a “new” sharpening method

                Noted re: hard felt wheels very inappropriate for all the reasons already gone over. 

                It is not obvious to me why I can use buffing wheels to dis-burr off the lathe/mill which most obviously changes the geometry and how/why that would not be the case with the "Unicorn" method to try to sharpen an edge tool.  However, I have no wish to argue for its own sake <G> so I will leave off on that.

                I was just wondering at the utility of buffing the edge vice simply honing it a couple of licks on an ultra fine stone/plate/strop/or whatever.  When I am working on a wooden model or carving; especially so with chip carving, I keep a ceramic hone, a Fallkniven DC-4 diamond/ceramic to be precise, on the bench beside my left hand and hone the knife/gouge/chisel whenever it starts to drag a bit.  I have yet to use the diamond side on a knife edge but it is handy to reshape the often rough back of a new blade (once every blue moon, I do have to change out an X-Acto blade since the tips of the finer blades like the #11 do get broken off when I fumble them onto the floor or something) and to dis-burr the knife point after several honings.  The DC-4 (as an airplane guy, I love that name) is about 1 1/4" by 4 inches so it is more than large enough for most chisel use too!  Well, except for my three widest ones (1 1/2", 1 3/4" and 2") that is; the big fellows and the plane irons get the same treatment with a diamond paste and Veritas compound treated bit of MDF that I also keep to hand when I work with those tools.  I cannot image having a power drill set out there for the same task when that little hone weighs about 3oz but perhaps that is just me. BTW one of these days, I plan to acquire some of those diamond lapping films from LV to make up another strop from some aluminium plate since I am curious about them.

                Thanks for the replies, an interesting notion for certain.

                Ken
                Les Groeller likes this.

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                • #9

                  Re: Unicorn - a “new” sharpening method

                  Originally posted by KenL View Post
                  I was just wondering at the utility of buffing the edge vice simply honing it a couple of licks on an ultra fine stone/plate/strop/or whatever.

                  Ken
                  Not to beat a dead horse...I get it that it might not be for you but all of your counterpoints are addressed in the article. A strop is not aggressive enough to have the same effect, and it retains burr particles to scratches the very tip of the edge. It's all about introducing a microscopic roundover at the very tip, and a soft wheel doe sit faster and in a more predictable/controllable way than any other medium. You could in theory do the same with a sharpening stone by lifting the blade to 45 on the last few strokes.

                  The benefits that have been shown through testing is not a sharper blade, but a much longer lasting one. That's it. I know that people like me have a lot of money and hours invested in our sharpening regimes, not to mention our own histories as to how we learned our methods. After all of this financial and emotional investment it's not necessarily easy to think that someone with a ten dollar chisel can get as good results as far as sharpness and edge durability goes than my $300 Japanese chisel. But that's what the results have shown. I'm not selling my Japanese chisels, nor my oil/water/ceramic/diamond stones, nor my diamond paste, not my strops, but I am incorporating buffing and more acute main bevels into my sharpening regime and so far the results are fantastic. Easier penetration fo chisels and longer lasting edges for everything.
                  Les Groeller likes this.
                  Frank
                  SPCHT

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                  • #10

                    Re: Unicorn - a “new” sharpening method

                    Well said.
                    The speed really does it for me.

                    The only downside at this point for me is the first couple of times spinning up the cloth wheel it looked like a cotton candy machine exploded. fluff everywhere
                    Frank D. likes this.
                    Cheers,
                    SPCHT

                    Comment


                    • #11

                      Re: Unicorn - a “new” sharpening method

                      I did peruse the article and even studied it a bit to ensure that I understood what they were trying to improve and why that would constitute an improved sharpening experience for me.  The answer seems to be, as usual, it depends on what you are tying to do with the tool.  Now and again, it is advantageous in paring and fitting to be able to use the chisel with the bevel acting as the reference face and that is only feasible if the edge is a true wedge ergo my disdain for micro-bevels.   Many of the points made about things like scratching the edge are only true if you didn't use appropriate cleaning technique when moving from one medium to another or not cleaning your final hone (ever).  Appropriate technique in the first instance nullifies those concerns IMO.

                      Their photograph shows that edge rounding is taking place, after all something had to give didn't it?  Nonetheless it is an interesting technique and could be of use if I didn't already know how to get things considerably sharper than a razor blade and keep them that way.   Great discussion.

                      Ken
                      Frank D. likes this.

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                      • #12

                        Re: Unicorn - a “new” sharpening method

                        Originally posted by Frank D. View Post
                        Hi Ken,
                        if you look at the article (I can provide a link...not at my computer now),
                        Hi Frank, could you post a link to that article? I can sharpen reasonably well, but have always struggled to get to a "beyond razor sharp" edge. I tried this method last night for the first time and it sure did the trick. I just had to barely graze the iron across my arm & the hair just fell away. So now I'm eager to learn more about the techniques & pitfalls.

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                        • #13

                          Re: Unicorn - a “new” sharpening method

                          Here it is... Pretty clear and concise.

                          http://www.woodcentral.com/cgi-bin/r...cles_958.shtml
                          Frank
                          SPCHT

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                          • #14

                            Re: Unicorn - a “new” sharpening method

                            Originally posted by Frank D. View Post
                            Here it is... Pretty clear and concise.

                            http://www.woodcentral.com/cgi-bin/r...cles_958.shtml
                            Thanks Frank.

                            Comment


                            • #15

                              Re: Unicorn - a “new” sharpening method

                              I tried using felt buffing wheels, both hard felt and loose.Both tended to round the edge more than I cared for. I made an MDF wheel that I put on my bench grinder and trued up on the grinder, then charged with green chromium dioxide buffing compound; it works excellent for stropping an edge, or even touching up an edge that's slightly dulled from use.
                              KenL likes this.

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