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Can't make my friends knives sharp

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  • #35674
    Knivmakeriet
    Participant
    • Topics: 1
    • Replies: 2

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    Hi everyone!

    I’m new here on the forums, I’ve  have been sharpening for a couple of years now and have had the wicked edge for a little over a year now.

    When I first started using We I had some trouble first getting the hand of it but then I practiced a while and got all my own knives sharp. I work as a sushi chef and have always had pretty high quality knives, mostly sg2 and some vg10.

    A few days ago a friend asked me to sharpen 2 of his victorinox knives and a 1 thick Shun chefs knife. I thought it would be quick work of the victorinox steel but I just can’t seem to get them right no matter how much I try!

    I feel like an idiot for not getting them sharp, I usually try to sharpen all knives at 15 degrees and I’ve been grinding away a lot of steel on them but still don’t feel like I ever hit a decent burr. . . I check with a sharpie to see if I hit the whole bevel and it looks like I find the sweet spot except for the tip on the left side where it looks like I accidentally made it a little convex (maybe I applied too much force and made it a different angle). I guess my question is if I may have accidentally screwed up his knife by removing too much metal and screwed up the bevel, I’m sorry if this post doesn’t make any sense, I’m on mobile right now and it’s kinda hard to type. But this is the first time I don’t know what to do with the knife anymore

    Any tips will be much appreciated, I have all stones from 50-1000 and a 2-3k naniwa as well as Nano strap and some spray if that helps.

    I can post pictures tomorrow when I get in to work if that helps anything .

     

    #35680
    Gregg776
    Participant
    • Topics: 1
    • Replies: 59

    I’ll take a stab at your problem, just bear in mind that this is my personal opinion and there may be better solutions.

    First of all VG10 ans SG2 are very different alloys from the softer stainless steels in most Victorinox knives; in other words the Victorinox needs a steeper (or more acute) angle to stay reasonably sharp and functional.  What you have done with the 15 degrees per side hasn’t hurt anything and may have actually thinned the cross section so that less effort will be needed to cut or slice.  The problem is that the softer steel won’t keep the edge you have so painstakingly tried to give it even through the sharpening process and certainly won’t hold up to to actually cutting much of anything.

    I’m assuming that your diamond and ceramic stones are broken in; that is they don’t leave scratches much larger or deeper than they are supposed to.  The simple solution is to take your 15 degree fine edge and put a micro bevel at about 22 degrees per side with a diamond stone using very light strokes at close to perpendicular to the edge (not sweeping strokes) which will give the knife some tooth and resistance to the edge rolling over.  I would start with 800 grit diamond and use some water with a little detergent on the stone to help lubricate and wash away the swarf.  You may want to experiment with grit and angle a bit depending on how the knife is used and who is using it. The micro bevel you want should be barely perceptible to the naked eye, but wide enough to keep the edge from rolling over and making a wire edge.  Search this forum for  micro bevel, wire edge and obtaining a burr and you will have a better understanding of some of what is involved.

    Remember to use light strokes and let the grit do the work; diamonds are not forever and pushing them too hard causes them to wear out prematurely but more important it causes the diamond particles to push metal much the same way a bulldozer pushes dirt leaving behind a weakened substrate and not lifting away all of the metal you really want to remove.

    True sharpness is totally dependent on blade metallurgy, heat treating, who is using the knife, what they are cutting and their expectations of edge longevity.  There is no magic one fits all solution.

     

    5 users thanked author for this post.
    #35683
    Knivmakeriet
    Participant
    • Topics: 1
    • Replies: 2

    I’ll try doing that! Great advice, it makes sense.

    When I work with victorinox and global knives as a lot of my friends do should I try with wider angles than 15 as I usually go with on my own? Or just become proficient at using microbevels ?

    #35689
    dulledge
    Participant
    • Topics: 12
    • Replies: 183

    Remember to use light strokes and let the grit do the work;

    I would print that words in bold in capital letters and put on a big banner on the wall. For microbevel it is critical that you should not apply any pressure. Microbevel is not visible to naked eye, it is very tiny. If you apply pressure, you will ruin it. Also you make only a few stokes, do not make many strokes. Microbevel is an art of its own.

    #35690
    dulledge
    Participant
    • Topics: 12
    • Replies: 183

    more important it causes the diamond particles to push metal much the same way a bulldozer pushes dirt leaving behind a weakened substrate and not lifting away all of the metal you really want to remove.

    Gregg, You put it so beautifully. It makes so clear picture of it in my head now.

    #35703
    Knivmakeriet
    Participant
    • Topics: 1
    • Replies: 2

    It worked like a charm Gregg, all 3 of them are in good shape now!

    You have a real way of explaining stuff, took me about 5 minutes

    #35707
    Gregg776
    Participant
    • Topics: 1
    • Replies: 59

    Keep reading the archives on this forum for a wealth of information on sharpening, particularly the microscope pictures some members have posted.

    A couple of years ago there were some links on this forum to some YouTube videos of electron microscope images of diamond abrasives and how they abrade metal in regards to sharpening edges.  I can’t seem to find the links but maybe some forum member can post a link.  These videos were very informative detailing the pushing of metal until it shears, the swarf buildup and how diamonds wear away.

     

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