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Advantages and disadvantages of different sharpening techniques

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This topic contains 61 replies, has 8 voices, and was last updated by  Mark76 10/14/2017 at 10:12 pm.

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  • #41506

    tcmeyer
    Participant

      Josh:  It all fits in with my viewpoint.  To me, “edge” can have two meanings, depending on whether you’re referring to the part of the knife that does the cutting (includes the secondary grind and its apex), or if you’re referring to the apex as one of the components that make up the secondary grind.  It depends on how specific you are in the reference.

      For examples:  When I describe a machete, I might say that it has an “edge” that includes everything that makes up the sharp side of the blade.   In a more specific case, I might describe how the machete has a nick in its edge and I am referring to the very edge, or to the “cutting edge.”

      More confusing for me has been the inconsistent use of “primary” and “secondary” grinds.  The Japanese apparently think of the relative importance of the grinds – the one that makes up the apex is the more important grind – therefor it’s the primary grind.  I look at it according to the second diagram in terms of which grind is done first.

      I disagree with the case of the zero-ground blade.  If the naming of the grinds is based on which is done first, the primary grind should still be called the primary grind.  If there is no second bevel which is done after the primary grind, there can be no secondary grind.   In any situation, knives or what not, use of the term secondary implies that there must be a primary.

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      #41507

      MarcH
      Moderator

        This is a good discussion.  Thank you both.  I just want to make sure everyone understands the debate or discussion of the terminology came out of my use of these terminologies with Mark76, who not only has the issue of the manner of use of these terminologies as TCMeyer uses them VS how Josh chooses to use them but Mark76 also is translating them from English to Dutch his native language.  So not only is there the issue of how one applies the terms but then what the terms mean and how they translate to Dutch!  So for Mark76 it becomes double or triple confusing.

        I agree with Tom that the inconsistent use of “primary” and “secondary” grinds is confusing.  Just to shake it up a bit more, in a “zero” grind blade where the entire side is the bevel, why isn’t the bevel called the blade flats in this case? or the primary bevel because there is only the one bevel, (like TC says)? or the secondary bevel because it’s the bevel you’re cutting with, (like Josh says)?  Now translate that to Dutch. LOL

        Thanks guys

        Marc

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        #41508

        Organic
        Participant

          I have seen on other forums where they have a glossary of agreed upon acronyms and terms in order to facilitate discussion and to help new members more easily understand what is being discussed. In my opinion, it would be useful for the WE forum to also have a similar glossary defining some of the commonly discussed terms. We have the beginnings of that in the knowledge base, but I think the primary / secondary bevels graphic that Josh just posted would make a fine addition.

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          #41524

          RazorEdgeKnives
          Participant

            I disagree with the case of the zero-ground blade. If the naming of the grinds is based on which is done first, the primary grind should still be called the primary grind. If there is no second bevel which is done after the primary grind, there can be no secondary grind. In any situation, knives or what not, use of the term secondary implies that there must be a primary.

            That is true Tom, I see your point!

            Just to shake it up a bit more, in a “zero” grind blade where the entire side is the bevel, why isn’t the bevel called the blade flats in this case? or the primary bevel because there is only the one bevel, (like TC says)? or the secondary bevel because it’s the bevel you’re cutting with, (like Josh says)? Now translate that to Dutch. LOL Thanks guys

            That is extremely rare, if it happens at all. What you are describing is a full flat zero grind, and if you have a full flat zero grind on most knives that would translate to such a fragile edge it would never hold up for daily use. Even well made Japanese knives, when full flat ground, always have some sort of secondary grind (i.e. another bevel that makes up the edge). The reason it wouldn’t be referred to as the ‘blade flats’ is because it has been ground into some sort of bar stock (or forged bar stock). So as Tom points out and you are correct, this would be primary grind/bevel.

             

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            #41525

            MarcH
            Moderator

              It all makes for interesting conversation and I have learned a lot from it.  Thank you Josh and Tom.  Josh it’s always good to get your input. And please let me know where I’m wrong.

              Presentatie1

               

              Marc

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              #41558

              Mark76
              Keymaster

                [ Edit: two people already thanked me for this topic. But I fell into sleep when I was halfway writing it. So now I finish it. ]

                Gentlemen, thanks for your explanation. I have tried to consolidate the information (and discovered a few inconsistencies). Could you please help me further?

                For the sake of simplicity, I’ll leave out convex knives, hollow knives and other unusually sharpened knives.

                I made a cross-section drawing of a knife that shows all relevant parts. Below I state the names you have given to them.

                Marc Josh first picture (“Murray Carter”) Josh (“Knife makers and users”)
                1. Flat Flat Flat
                2. Bevel Edge Bevel (possibly hollow in his pic)
                3. Bevel (even if it is zero ground) Edge Bevel

                 

                Josh also uses, in his second picture, the term grind as a synonym for a bevel.

                Basically, I think we can say MarcH and Josh can agree on the term bevel where the “knife makers and users” are concerned. The Japanese and the “knife makers and users” use the term bevel where the others use the term edge and vice versa.

                Josh also uses the word edge as a synonym for the secondary bevel (his second pic) This confuses me since according to MarcH, the edge is the complete set of bevels. Personally, I find the former meaning more appealing.

                Tom points out that the terms “primary” and “secondary” are used wrongly by us “knife makers and users”. (My interpretation: Tom favors the Japanese meanings of these terms, where the primary bevel/edge is closest to the apex.) He writes “In any situation, knives or what not, use of the term secondary implies that there must be a primary.” I tend to agree with that.

                And finally, if somebody uses the term regrinding, it would be useful if they stated what they are regrinding: either the secondary bevel (Josh’ terminology) or something more, like also the primary bevel or even the entire blade.

                In Dutch we solve this very elegantly: we call both a bevel and an edge a “snijvlak”. Which is quite useful if you want to avoid confusion 😊 . It is less useful if you want to be more precise like us, but then you should be consistent in your use of the words…

                I’m glad I’m not the only one having problems understanding these words 😊 . But to be clear, can we (as a part of the WE forum users) say that an edge is made up out of multiple bevels and that a grind is a synonym of a bevel? Or do we use the word edge for something else (like the primary bevel – or secondary, depending on one’s interpretation)? And how about primary and secondary? I agree with Tom, but of course, we are not alone in the world and using words in a meaning that many others don’t is not very useful.

                Molecule Polishing: my blog about sharpening with the Wicked Edge

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                #41572

                MarcH
                Moderator

                  Once you’ve created that burr, you will have an apex that is way off center. Does this mean you shouldn’t file the edge flat if your only method of finding the apex is by feeling for a burr? I think so.

                  Yes, I think that’s true if you’re using scrubbing motions on one side to draw a burr. If you’re using alternating strokes for most of it, you can keep it pretty centered but it would definitely take longer.

                  I’m sharpening a knife right now that I chose to “distress” the edge, that is I filed it flat and perpendicular, to remove all the bad chips and damage to the apex.  I never realized just how hard and how much material I had to remove from both sides to move the bevels down to create a new fresh apex.

                  I started by matching the angle and finding the “sweet spot” using the sharpie.  After flattening the bevels on both sides I realized when inspecting the bevels with the USB scope just how terribly damaged the apex was.  Then at this point, I “distressed the edge”, which like Tom says totally obliterates the apex.  The stones angles are set to rest flat against the bevels.  As I employ scrubbing strokes alternatingly to bring the centered apex back, I am removing metal along the entire flat bevels heel to tip, on both sides of the knife as I grind, or profile the bevels lower and lower or closer to the spine while maintaining the same exact sharpening angle.  It’s a long slow process and I did need to work alternatingly monitoring my progress to keep the apex centered.

                  I don’t know any other way to do. Maybe it’s better to distress with the file at an angle VS perpendicular to the knife?  Maybe file a bevel like angle on one side than repeat the filed bevel like angle on the other.  I may employ this method the next time.  I think it will require I remove less metal when sharpening to bring back the fresh centered apex.  This probably is exactly what TCMeyer was saying!

                  Marc

                  #41575

                  MarcH
                  Moderator

                    Maybe it’s better to distress with a file at an angle VS perpendicular to the knife? Maybe file a bevel like angle on one side than repeat the filed bevel like angle on the other. I may employ this method the next time. I think it will require I remove less metal when sharpening to bring back the fresh centered apex. This probably is exactly what TCMeyer was saying!

                    I just did this….  I clamped a very distressed, chipped edge knife in the WEPS vice.  I took an actual metal file to the edge and filed it at an obtuse angle, both sides, to remove the holes and chips and create a rough bevel.  It worked pretty well.  Then I found the old sharpened angle, 19º, with the remains of the distressed bevel using the sharpie and found the sweet spot.

                    I decided to try my new 50/80 WE Diamond Stone.  I set both side bevels and apexed the edge with one quickie up/down scrub on each side.  It took about 2 minutes!  The 50/80 sure is aggressive.  I’ll keep using it as a time saver and to eventually, break it in.  They’re certainly is an advantage when I employ the right tools!  Here’s a picture of the 50 grit bevel, (250X):

                    50-grit-bevel

                    Marc

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                    #41584

                    tcmeyer
                    Participant

                      (My interpretation: Tom favors the Japanese meanings of these terms, where the primary bevel/edge is closest to the apex.)

                      Hi Mark:  I really like when other forum posters agree with me, but in this situation I think you’ve incorrectly inferred something from my statement.  In fact, I much prefer the use of “primary” and “secondary” as describing the sequence in which they are made.    If you’re using the “secondary/primary” method versus the “primary/secondary” method, the names of the existing bevels would change if you added another bevel, resulting in further confusion.

                      Maybe there should be a “first” bevel and a “final” bevel.  If there are multiple intermediate bevels, they would be called “second” and “third” bevels, etc.. Would a microbevel be a “tertiary” or third bevel? In the diagram you just posted, I think it’s understood that the number 2 bevel is the primary bevel, but it would be more clearly named as a “face” bevel, saving the terms primary and secondary to those facets which actually make up the cutting edge.

                      Unfortunately, I don’t write the book on knife nomenclature.  Darn.  Where’s that emoji when you need it?

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                      #41585

                      Mark76
                      Keymaster

                        Tom, I just googled it (again). My intention was/is not to invent the best meaning of the words primary and secondary (or bevel and edge), but just to learn how other people use these words. In this case Google Images was very useful. I’d say that 90% of the English speaking world agrees with the meaning Marc and Josh give to the words primary and secondary. For example (pic from Google Images):

                        Funnily enough, fewer people seem to agree on the meaning of the words bevel and edge and it is not just the Japanese who use the word edge for the completely flat part (for which Josh and Marc favor the word bevel or grind). Here’s an example, again from Google images:

                        Darn. Where’s that emoji when you need it?

                        I don’t know which emoji you want, but here are a few:

                        🙂  😉  😀  🙁  😐

                        Molecule Polishing: my blog about sharpening with the Wicked Edge

                        #41586

                        tcmeyer
                        Participant

                          I think these diagrams are adding to the confusion.  I can’t tell from the first diagram if the primary bevels extend up toward the spine and are actually the face grinds, or if it’s a blow-up of the bevels we produce with our WEPS.  I do agree with the “primary/secondary/microbevel” nomenclature if it’s the latter.

                          I’ll take that little yellow bugger with the big smile.

                          #41588

                          MarcH
                          Moderator

                            All I can say is what ever you choose to use, use the terminology in a way or with a picture or drawing that makes it clear your intentions.  Mark76 the two drawings above say the same thing using different terminology, bevel and edge.  I do not have any problem with either use.  I understand them both especially when attached as labels to a picture.

                            I agree with Tom logic that the nomenclature should correlate with the order that the grind in created from the knife blank or flat.  First ground surface should be the primary ground.

                            If I were to use “primary edge” in a sentence I would elaborate with adding, “the edge that does the cutting”.

                            I have never seen or sharpened a knife with a primary bevel, a secondary bevel, then also a micro bevel…That looks like a sharpening error to me or something someone’s trying to salvage to just make it work until the next re-profiling fixes it!

                            Marc

                            #41589

                            RazorEdgeKnives
                            Participant

                              When I’m speaking to customers and they say “I would like you to reprofile the primary edge” then I automatically think that they are referring to the edge that first contacts the cutting medium. Likewise, if they say “I would like you to set the secondary edge to 15 dps” then I will basically interpret that as meaning they want the edge set to 15 dps w/ some sort of microbevel. In either case I would have to clarify exactly what they are meaning.

                              Tom, in Mark’s 1st picture it is basically the same thing as what I posted – a cross section of an entire knife blade. So the flats would be the sides of the blade that would be surface ground flat prior to attaching the scales (on a fixed blade).

                              Mark, I think you are getting hung up on the terms bevels/grinds instead of the more important terms imho, which are ‘primary’ and ‘secondary’. These are what describes where the bevels/grinds go and what they do. Technically a microbevel would be a tertiary or third bevel, Tom is correct on this.

                              Marc, I do blades w/ a primary bevel, secondary bevel, and add a micro all the time (but I don’t add a relief also if you were referring to Mark’s diagram above). For example, this ZT was done in this manner. Primary bevel regrind, secondary bevel set to 15 dps, w/ a 16 dps microbevel (secondary and micro are mirror polished – you can never see it unless under high power magnification):

                              #41590

                              MarcH
                              Moderator

                                Marc, I do blades w/ a primary bevel, secondary bevel, and add a micro all the time (but I don’t add a relief also if you were referring to Mark’s diagram above). For example, this ZT was done in this manner. Primary bevel regrind, secondary bevel set to 15 dps, w/ a 16 dps microbevel (secondary and micro are mirror polished – you can never see it unless under high power magnification):

                                Josh when you say it in those practical, real-life, terms I get it and I agree, I’m familiar with that sharpening application.  When I looked at the blunt, out-of-proportion stick drawing it seems odd.  I think you’re exactly correct when you said, ” When I’m speaking to customers and they say “I would like you to reprofile the primary edge” then I automatically think that they are referring to the edge that first contacts the cutting medium. Likewise, if they say “I would like you to set the secondary edge to 15 dps” then I will basically interpret that as meaning they want the edge set to 15 dps w/ some sort of microbevel. In either case I would have to clarify exactly what they are meaning.” 

                                That’s what I believe I wrote above in an earlier post… as long as we clarify there’s no confusion.  Again to reiterate, this discussion began with Mark76 trying to understand while translating terms from English, not his native tongue, to Dutch, his native language, terms as we see can be used ambiguously which when literally translated with “book definitions” don’t necessarily match a knife maker or knife sharpeners use of this terminology in real life.

                                I think we all can work with this common ambiguity and use either or both definitions as long as we clarify exactly what we mean when it’s important enough to avoid misunderstandings.  I don’t think it’s necessary, important or practical to try to get everyone to agree and employ a common set of terminology.  It would be too difficult, cumbersome and IMO unnecessary.

                                BTW, Josh… that’s another beautiful knife you’ve done there.

                                Marc

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                                #41591

                                Mark76
                                Keymaster

                                  I think you’re right, Josh. The reason I put so much emphasis on these words is not that I don’t understand someone; if I don’t I can always ask what they mean. The reason is that I, not being English or American (but almost Australian 😉 ) , would like to get my words right and try not be corrected for incorrect use of English.

                                  And yeah, that is a beautiful ZT.

                                  Molecule Polishing: my blog about sharpening with the Wicked Edge

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