Announcement

Collapse
No announcement yet.

Carbide kitchen knife

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Originally posted by challenger View Post
    Not a think to lose .

    You said it not any or us... it's a classic though lol

    Comment


    • #17
      Originally posted by A.K. Boomer View Post


      You said it not any or us... it's a classic though lol
      Well now... perhaps you better turn in your typo policeman's badge.
      Lynn (Huntsville, AL)

      Comment


      • #18
        Originally posted by lynnl View Post

        Well now... perhaps you better turn in your typo policeman's badge.
        Im not as think as you drunk I am lol

        Comment


        • #19
          "Carbide", as used in a cutting tool, is not one material. It actually is the carbide material, in "chunks", held in a matrix.

          The reason why carbide is generally not able to be sharpened to a fine durable edge, is because at some point you get down to a thin bit of the matrix, with some partial "chunks" sorta embedded in it. The "partial chunks" aer not held solidly, and can fairly easily tear out of the softer matrix. The result is quick dulling of the edge until the point where the chunks are held well enough to do their work.

          The finer the "chunk size" potentially the sharper the edge can be made before the "chunks" are easily knocked out of the matrix. I have no idea how fine is now used, but sharp knives have extremely fine edges. I don't know dimensions for that, but it's small.

          Single crystal carbide, if it can even exist or be made, would be what you want. Then the entire knife, or the entire edge, could be the carbide. Probably would be brittle, and so expensive that it would be far beyond impractical unless demand were high enough to develop a process for making it.
          2730

          Keep eye on ball.
          Hashim Khan

          Everything not impossible is compulsory

          Comment


          • #20
            Originally posted by Willy View Post
            appears to me to be a new technology, well to me at least, as I like others have known most machining grade carbide to be brittle, although there are hard and brittle grades and tough grades.
            Although I have in the past used snow plow blades on highways maintenance trucks that used carbide inserts that stood up way way longer than abrasion resistant steel blades, unbelievably longer!
            Also have seen carbide used in highways milling machines used for reclaiming old roadways as material for new asphalt, tough stuff to be sure.
            Aye, not going to say that carbide cant be tough, things like those highway millers prove that it can be. My argument is that carbide is brittle at certain edge geometries. A piece of carbide with a 90 degree edge is going to have a much tougher edge than a piece with a 10 degree edge, even when made with the same grade. Same thing happens with steel too. Kitchen knives work best with extremely thin edges and very low bevel angles, thinner and lower makes for sharper, makes for better slicing. Looking at those Sandrink knives, they kinda cheat in this regard by going for a higher bevel angle, in the case of their kitchen knives a 21 degree Scandinavian grind. Not a bad grind for a general purpose knife, but not really ideal for a kitchen knife. For reference, when i make a kitchen knife, i go with a full flat grind at 3-5 degrees until the edge thickness measures about .005-.010" thick, then sharpen at about a 7-10 degree angle. Makes for an incredibly thin, incredibly sharp edge. Not claiming that the Sandrin knives arent sharp, but ill confess im skeptical on how well they measure up to a knife made out of something like AEB-L

            I, err, i make knives. Kinda have strong opinions on the subject, if it didnt show. Im incredibly skeptical of anybody who claims to have a new "wonder material", particularly when said material focuses almost exclusively on the hardness rating (which is about the most useless metric for a knife)

            Comment


            • #21
              Originally posted by epicfail48 View Post

              I, err, i make knives. Kinda have strong opinions on the subject, if it didnt show. Im incredibly skeptical of anybody who claims to have a new "wonder material", particularly when said material focuses almost exclusively on the hardness rating (which is about the most useless metric for a knife)
              Ha! Well thats interesting. I did not know that about you. I like!

              I dont make knives. I inport Japanese knives here to be reworked. It is not even on the level that you do. I applaud you. All I do is finish and fix knives. Some fixes are just over the top, Idiots! What were you doing I think? Hahaha.

              Yeah, I dont have the skill to make a knife. I can finish one though

              Nice to see there is a knife mechanic here also.

              I can sharpen your blade if you need. Mirror finish? Ok JR

              Comment


              • #22
                Originally posted by JRouche View Post
                Yeah, I dont have the skill to make a knife
                I call bollocks on that. Anybody can make a knife, and a good knife at that. Honestly the basic process isnt difficult

                That said, it does take some skill to make the best knife, one that pushes the limit of what the steel is capable of and does the task the knife is designed for perfectly. Doing that takes some serious effort, because not only do you have to have the mechanics of the shaping and grinding and polishing down pat, you also need to have the knowledge of why youre doing what youre doing, how things like heat treatment and edge geometry impact the final product. Its a lot like welding, anybody can get 2 pieces of metal to stick together, but it takes a master to produce a textbook weld on an exotic alloy thatll pass any certification necessary

                Comment


                • #23
                  Originally posted by RB211 View Post
                  Haven't we dispelled the old wives tales that Carbide can't hold a sharp edge?
                  That was never an old wives tale, when used at a geometry appropriate to its brittleness. Anyone who scrapes knows carbide will hold a sharp edge longer than tool steel; at the scrapers the geometry. i.e. 93 degrees included angle. Carbide has improved and become less brittle such that smaller included angles might now last longer than they used to, but a kitchen knife is a 20 degree angle. Carbide is more brittle than tool steel, the more acute the included angle, the more likely this is be an issue.
                  in Toronto Ontario - where are you?

                  Comment


                  • #24
                    Well, a few things if I may:
                    1-sorry for the auto spell error (not really😬)

                    B-I am including some photos that show the blades I have and the manufacturer. The photo will show a VERY sharp edge on these blades.

                    € - The blades are 3mm thick FWIW

                    1 - WHAT would be a better material for the blade edge of my Bubba Blade? I catch, and clean, almost exclusively redfish. They have extremely tough scales and I can't seem to keep a hair shaving wire edge on the blade. I'm obsessive about having a knife that will shave the hair on my arm. I have a bunch of $ invested in sharpening equipment but I can't keep the wire edge on the Bubba Blade. If I hit bones it's "dull".
                    I also use a piece of bent magazine paper as a measurement of the sharpness. I also wear a cut proof glove when I clean fish because the knife will cut me, when it's sharp, and I won't know it until the blood flows. Then I get my suture kit out and sew on.
                    Thanks Click image for larger version

Name:	PXL_20210923_125255041.jpg
Views:	260
Size:	4.19 MB
ID:	1962662 Click image for larger version

Name:	PXL_20210923_125314374.jpg
Views:	252
Size:	4.16 MB
ID:	1962663 Click image for larger version

Name:	PXL_20210923_125321355.jpg
Views:	260
Size:	4.25 MB
ID:	1962664

                    Comment


                    • #25
                      Originally posted by epicfail48 View Post
                      ...........................

                      I, err, i make knives. Kinda have strong opinions on the subject, if it didnt show................

                      The question, which you may know the answer to, is "what is the thickness of the actual cutting edge on a very sharp knife"?

                      If you go by the idea that the edge should be "invisible", then you have your choice of the resolving power of the human eye, or somewhere around the wavelength of visible light. My money is on the resolving power of the eye, which is probably a fair bit coarser, but not being a knifemaker, I have never looked into the matter.

                      2730

                      Keep eye on ball.
                      Hashim Khan

                      Everything not impossible is compulsory

                      Comment


                      • #26
                        Originally posted by J Tiers View Post


                        The question, which you may know the answer to, is "what is the thickness of the actual cutting edge on a very sharp knife"?

                        If you go by the idea that the edge should be "invisible", then you have your choice of the resolving power of the human eye, or somewhere around the wavelength of visible light. My money is on the resolving power of the eye, which is probably a fair bit coarser, but not being a knifemaker, I have never looked into the matter.
                        As a novice knife edge spirt, the knife edge is less than the width of tin foil. My stab would be far less than 001.
                        Hopefully this post will prompt some real life answers because 001" seems WAY too much....

                        I, once again, sharpened my knife today. I used a home made ceramic contraption made from two ceramic inserts. I screwed these inserts to a piece of nylon "plate" and made the angle to match the knife angle I currently had. After just a few strokes, using water as a lubricant, the knife popped the hair off my wrist like a hot knife through butter. I then polished the edges on a leather strop with some buffing compound. This made the edge look pretty but didn't improve the hair pop test???
                        Last edited by challenger; 09-23-2021, 01:38 PM.

                        Comment


                        • #27
                          Originally posted by epicfail48 View Post

                          Aye, not going to say that carbide cant be tough, things like those highway millers prove that it can be. My argument is that carbide is brittle at certain edge geometries. A piece of carbide with a 90 degree edge is going to have a much tougher edge than a piece with a 10 degree edge, even when made with the same grade. Same thing happens with steel too. Kitchen knives work best with extremely thin edges and very low bevel angles, thinner and lower makes for sharper, makes for better slicing. Looking at those Sandrink knives, they kinda cheat in this regard by going for a higher bevel angle, in the case of their kitchen knives a 21 degree Scandinavian grind. Not a bad grind for a general purpose knife, but not really ideal for a kitchen knife. For reference, when i make a kitchen knife, i go with a full flat grind at 3-5 degrees until the edge thickness measures about .005-.010" thick, then sharpen at about a 7-10 degree angle. Makes for an incredibly thin, incredibly sharp edge. Not claiming that the Sandrin knives arent sharp, but ill confess im skeptical on how well they measure up to a knife made out of something like AEB-L

                          I, err, i make knives. Kinda have strong opinions on the subject, if it didnt show. Im incredibly skeptical of anybody who claims to have a new "wonder material", particularly when said material focuses almost exclusively on the hardness rating (which is about the most useless metric for a knife)
                          No argument from me on what you say.
                          The makers of the Sandrin knives main claim to fame is edge retention and to some point ductility with their poyhedral tungsten carbide. I think we can all agree that both of these terms are largely subjective much as is the term "sharp".

                          From the several video clips I've seen of the Sandrin knives slicing through vegetables they do not appear to me to be incredibly sharp, nor the answer to a chef's prayer. Although edge retention should at least offer some solace.

                          But for me, I'll stick to a quality steel blade, I'm not ready yet to toss my $200+ into the hat in order to find out personally

                          Their frequently asked questions page offers a lot of insight into what these knives are and what to expect.

                          I do wish challenger well in his quest for what he needs his knife for, I truly hope he succeeds and hope he reports back with his findings. One way or another we can all learn something from his work. I don't think he intends to use it for prying open a stuck window but as long as he can get the edge he needs and the ability to not get dull after striking a few bones, he's a winner.
                          Home, down in the valley behind the Red Angus
                          Bad Decisions Make Good Stories​

                          Location: British Columbia

                          Comment


                          • #28
                            Originally posted by J Tiers View Post


                            The question, which you may know the answer to, is "what is the thickness of the actual cutting edge on a very sharp knife"?

                            If you go by the idea that the edge should be "invisible", then you have your choice of the resolving power of the human eye, or somewhere around the wavelength of visible light. My money is on the resolving power of the eye, which is probably a fair bit coarser, but not being a knifemaker, I have never looked into the matter.
                            Unfortunately I don't have a concrete number for you there. The ideal knife edge takes down to a single atoms thickness, but the real world is hardly ideal. A properly sharp edge is invisible to the naked eye, and I'd wager that you'd need pretty hefty magnification before you could see the flat. If I had to pull a number out of my posterior, I would guess the thickness being somewhere in the neighborhood of a few millionths, if that

                            Comment


                            • #29
                              C'mon folks! 😬. I have to believe there are a few here, at least, that can quantify the ideal, realistic, knife edge. I'd suspect this would also depend on the blade material but this is far above my pay grade. Let's hear it!

                              Comment


                              • #30
                                There would have to be some trade-off. Any practical material has a limit of sharpness, beyond which the edge is not durable. It may bend, chip, etc, but the strength of a very thin edge is not going to be wonderful even for good steel.

                                The samurai swords have lots pf legends about sharpness, but they seem to be layered, probably reasonably finely layered, but very thin layers might take a bit of work. Every fold doubles the layers, which then are thinned as the blank is drawn out to form the sword. The drawing out process seems to be anywhere from 10:1 to 15:1, judging by eye.

                                One might get a hint about thickness from the swords, based on the idea that the edge must be about a layer thick at the least.
                                2730

                                Keep eye on ball.
                                Hashim Khan

                                Everything not impossible is compulsory

                                Comment

                                Working...
                                X