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Micro bevel, looses edge

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  • #45591
    phil
    Participant
    • Topics: 1
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    Hi All, new to the forum and the WE. Just picked up a Pro-Pack II. I’ve done a few knives and still getting a hang of it, but the results have been good.

    There’s one issue I have that that need some input on since I’m sure it’s operator error:

    I’m able to get the blades super sharp if I do a single bevel at 15 dps, confirmed on multiple blades. The problem is when I do a micro-bevel after this. I’ve done them at both 18 and 20 dps and the blades just aren’t as sharp after the that. They don’t slice through paper or shave hair like they do before the micro-bevel.

    I’m doing the micro-bevel with 1000 grit and about 4 passes per side. Should I use a finer grit like 1500 or ceramics?

    The main reason I want the micro bevel is so I can touch the knives up easily on the sharpmaker afterwards at 20 dps.

    Thanks in advance.

     

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    #45592
    MarcH
    Moderator
    • Topics: 59
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    Welcome to the Wicked Edge Forum and WE Community, phil.

    I’ve seen users apply microbevels with very fine grit stones like you used and also more coarse stones like 400 grit.  So I can’t say which works best.  I prefer a very fine grit the few times I have applied a microbevel.  To enhance the microbevel’s sharpness you might want to try to strop the edge after applying it.  I’d lightly strop at 1º less than the microbevel angle.

    Marc
    (MarcH's Rack-It)

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    #45593
    Organic
    Participant
    • Topics: 17
    • Replies: 928

    If you have a microscope or jeweler’s loupe I would recommend inspecting the edge to ensure that you’ve actually apexed the knife with the micro bevel. Stropping after the application of the micro bevel is also a good suggestion.

    Regarding grit; the ceramic stones make a very nice micro bevel in my experience, but nearly any grit should work.

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    #45594
    tcmeyer
    Participant
    • Topics: 36
    • Replies: 1905

    Phil:  A drop-off in perceived sharpness is to be expected when adding a micro-bevel to an already sharp edge.  Micro-bevels are typically created with coarser grits than the main bevels, and are used for either of, or both purposes, which are (1) to add a toothy edge to aid in cutting into certain tough and/or slippery materials and (2) to reduce the tendency of an acute edge to fracture or deform under expected cutting loads.   The amount of difference in perceived sharpness is greater where the main bevels are polished and the apex is highly refined.  It may be even greater where the main bevel angles are quite low (for example: < 18 dps).  If you slice open a common business envelope with a polished and refined 16 dps edge, the cut will be extremely smooth, requiring little force and be almost silent, as opposed to what you’d experience with a nylon letter opener.  Make the same cut after adding a 20 dps, 1000-grit micro-bevel – even with only 3 very light strokes – and the increase in force required and the increase in noise produced with be readily apparent.

    Assuming that you have made no angular errors in creating the main and micro-bevels, and that the pressure applied with the stones at the micro-bevel stage is light, there is no reason why there should be an unacceptable drop-off in sharpness.  As Organic suggests, your best next step would be to inspect the edge optically.  A well-executed micro-bevel should be so fine that it is almost invisible to the unaided human eye.  When I return a knife to its owner, they will almost never notice that there is a micro-bevel unless I point it out to them.  In a few cases, I’ve provided the owner with a micro-video of the edge, so that they will understand what they’ll be dealing with if and when they attempt to sharpen it manually.  If they do not take the micro-bevel into account, their efforts will be for naught.

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    #45595
    sksharp
    Participant
    • Topics: 9
    • Replies: 397

    Hey Phil,  micro bevels are difficult with new stones. The roughness of new diamonds makes it difficult to refine the edge with just a few strokes. The diamond stones do start to break in at 10 or so knives, but wait until you have had 100 or so on them. The difference in what you can achieve with fully broken in stones is amazing.

    I do most of my micro bevels with the last stone in my progression or with micro ceramics, 1.4/.6, not to change the characteristics of the cutting edge but to add durability and ease of maintenance. Like TC said above there are a lot of different reasons and methods to apply micro’s so using test knives and working some things out will help you gain the techniques and methods that will work for you. You will see a slight drop off when applying a micro if tested before stropping. If stropped properly you should not see much difference at all in “perceived” sharpness. With a micro bevel I strop at the same or -.5 deg. as the original sharpened angle. The micro ceramics were very easy and the best way for me to learn micro bevels simply because they don’t remove metal very fast allowing you to refine the micro bevel a bit more, more passes, without widening the micro to much.

    One of my preferred methods is thru 1500 diamond, then 5 to 10 passes with the 1500, very light but make sure to use enough pressure to keep consistent pressure. I increase the angle for the micro by 2 or 3 deg., I prefer 2. Then I move back to the original angle and strop making sure not to use to much pressure and test frequently. You should see the sharpness that you lost come back very quickly after you start the stropping. The angles that I use the most are, 20/22 micro, 17 or 18/20, and 15/17. These are the one’s I use the most. You can use more passes when setting a micro bevel but remember the wider the micro bevel gets the more it takes on the characteristic of the more obtuse angle.

    If there is anything that I can help you with on this don’t hesitate to ask.

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    #45597
    phil
    Participant
    • Topics: 1
    • Replies: 1

    Thank you for your responses. This makes sense and is educational.

    I’ll let you know how things turn out.

     

    BTW, this was on a Spyderco PM2. It can still cut paper after the micro bevel, but I need to pull the knife, push won’t do it. It makes sense now.

    Thanks again.

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    #45658
    Expidia
    Participant
    • Topics: 46
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    I’ve been following this micro bevel vid by clay and its been working for me.  He was using a 200 grit which gives a nice toothy edge for some of my kitchen knives.

    I have two large thin Japanese chefs knives.  One with a fine 1000 grit micro bevel that I use for slicing and the other with a 200 grit micro bevel that I use for cutting.

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