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number of passes

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  • #57053
    Jeffrey
    Participant
    • Topics: 1
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    I’m new to the system, and have read quite a number of hints. My question is (and I know the number is highly variable), what is an order of magnitude to first sharpen a VERY dull knife with a hardness of german kitchen steel (Wusthoff, Henckle, 56-58 Rockwell etc).  I’m looking to create an angle of 20° starting with a 100 diamond and working toward 600. No pressure on the blade other than the stone.  Is to 10 passes, 50, 100? Anyone have some experience to share?

    #57054
    NorCalQ
    Participant
    • Topics: 51
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    Others with more experience will chime in.  Tough question.  Kinda depends on how dull the blade is.  I can say the number for me has been closer to 100 strokes, but it’s really about when the burr is formed.

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    #57056
    MarcH
    Moderator
    • Topics: 64
    • Replies: 2469

    Welcome to the forum Jeffrey.

    I prefer to use a results driven method for knife sharpening.  Like NorCalQ wrote above,  it “kinda depends”.

    I visually inspect the edge I’m starting with.  This helps me to determine my starting grit based on the condition of the edge or level of damage there may be. Then, I continually spot check the edge as I work it with the grit I choose to use to bring the edge’s profile back. I’m not a stroke counter.  I do whatever it takes to get the bevel ready to move up to the next finer grit.  Grit after grit.  If I feel like I’m working too hard at it with my grit first choice, I drop down to a more coarse grit, then get back at.  Sharpening and inspecting. Only when it looks and feels right do I move on.

    By “feels right” I mean I do simple finger touches, a “spot check”, down along the sharpened edge to feel my sharpening progress.  Also, there is a distinct feel up through the sharpening stones, a feed-back mechanism sort of, and there’s even a sound change that is noticeable. These I use to clue me into my edges progress towards getting sharper.

    Each grit should get quicker and quicker, requiring less time and effort before I can move on..

    With my technique I do keep track of my edge work, so I can keep it balanced and even from side to side.  I wouldn’t want to spend too much more time working one side over the other, unless, what I’m seeing and feeling dictates that’s what I need to be doing.  My last sharpening strokes I’ll use to finish with each grit are alternating side, left-right-left-right-left-right-left-right sharpening strokes.  This in itself is in essence a counted stroke without actually counting.  Stroke counting is intended to keep the bevels even.  It’s a good practical method when there’s no visual aid.  If you can see the progress, I prefer to work the edge as long as it appears to be necessary to see that it’s done.

    This is not to say that counting is not a valid sharpening method used by some knife sharpeners. I just don’t actually count, 1,2,3…..

    Marc
    (MarcH's Rack-Its)

    #57057
    000Robert
    Participant
    • Topics: 6
    • Replies: 280

    It also depends on if the blade apex needs to be reprofiled. I don’t start counting strokes until the apex is perfect and I get good burrs on both sides after reprofiling the edges. And nearly every knife that I have sharpened the first time needed to be reprofiled.

    #57059
    rummels
    Participant
    • Topics: 7
    • Replies: 34

    Jeffrey

    Because there are so many variables (the type of stone, the stone’s grit, the pressure you apply to the stone when sharpening, the hardness of the steel, how much the edge needs to be reprofiled, etc), you have to use a “results driven” process like those described above.  You have to be guided by the changes you are making to the edge and not the number of strokes.  This concept applies to all aspects of sharpening, whether you are reprofiling an edge, resetting a previous edge, deburring, stropping, etc.

    I usually start with a 400 grit diamond stone, but if I am not happy with the speed with which the stone is effecting the edge, I will drop to a coarser grit.  So start on one side and sharpen that side with your 100 grit stones until you have definitely created a burr on the other side of the apex.  If you start on the right side of the edge, the burr will be felt on the left side.  Then sharpen the left side and continue until a burr can now be felt on the right side of the edge.

    If your goal is a 600 grit edge, follow the same process with the 200, 400 and 600 grit stones.  After using the 600 grit stones, it’s will be time to remove the second burr you created with the 600 grit stones.  Search this and other forums for methods of how to deburr a coarse, toothy edge.  There are a number of approaches that will yield good results.  Find the one that works best for you.

    rummels

     

    • This reply was modified 2 weeks, 1 day ago by rummels.
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    #57072
    tcmeyer
    Participant
    • Topics: 37
    • Replies: 2026

    I think I’m pretty much in agreement here, but I’d add that the number of strokes depends heavily on the thickness of the edge  – as measured at the shoulders of the bevels (or the width of the bevels) .  A very thin edge will require very few strokes.

    Assuming single diagonal strokes, short blades require fewer strokes because the steeper diagonal angle results in more abrasive movement per inch of blade.  With blades longer than about 5″, the angle is so low that there is really no difference between 5″ and 12″, as far as numbers of strokes required goes.  I usually establish an apex with 400 grit, however many strokes that takes, then follow up with 15-20 strokes per grit depending on bevel width.  More if I’m looking for a mirror edge, which is not too often, less if it’s a cheap knife.

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