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WE 120 angle difference per side?

Recent Forums Main Forum Techniques and Sharpening Strategies WE 120 angle difference per side?

This topic contains 7 replies, has 5 voices, and was last updated by  MarcH 05/11/2019 at 12:38 pm.

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  • #44363

    Stephen
    Participant
    • Topics: 2
    • Replies: 0

    i tried looking for this, I may not have the proper search parameters. On a knife with a thick spine, I’m noticing a distinct difference in the right ground angle versus the left. On one knife I chalked this up to a rounded spine, but it also occurred on a Schrade SCHF9 with a flat spine. Am I missing something on setup? Any tips?

    #44365

    wickededge
    Keymaster
    • Topics: 121
    • Replies: 2901

    Hi Stephen,

    You’re not wrong in seeing a shallower angle on the right side of thick knives. The sharpen is designed around an average blade thickness of 1/8″. If it is wider, you can move the right angle out a little, generally about 1 degree per additional 1/8″ thickness. In cases where the thickness isn’t close to a 1/8″ increment, set the angle wider on the degree bar and then adjust it a little lower w/ the micro-adjustment.

    -Clay

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    #44366

    MarcH
    Moderator
    • Topics: 58
    • Replies: 1884

    Stephen you are correct.  The nature of the vice design, screw type clamp, has one side that moves, (right) and the other side is fixed or stationary, (left).   This design characteristic causes clamped knives to lean a small amount to the left when clamped.  This is particularly noticeable with flat ground and full flat ground knives.  The lean can be corrected by setting your individual side rod angles to compensate for it.  There are YouTube Videos and lots of posts on the forum that explain how to correct for the lean.

    I believe this is the correct method:  Measure with an angle cube the angle of the flat surface of your blade both the left and the right side, as it’s mounted ready to sharpen.  It is a small angle because your just leaning a little bit off of perpendicular. It is 90º + the angle on one side and 90º – the angle on the other side. The two angles are added together, then the value is divided in half.  The half value is added to the left side rod angle setting and subtracted from the right side rod angle setting.  This should compensate for the lean or blade “cant”.  I believe this is correct and like I said someone will surely chime in to lend you a hand and correct me if I’ve told you wrong.

    Marc
    (MarcH's Rack-It)

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    #50462

    airscapes
    Participant
    • Topics: 10
    • Replies: 192

    Ok now I am really confused.

    @clay  Are you saying  the left side of the knife will be correct and only the right side gets adjusted?

    #50481

    tcmeyer
    Participant
    • Topics: 33
    • Replies: 1852

    Clay’s comment refers to the fact that the centerline of the knife moves to right as the spine thickness increases.  Basically, what he is saying is that the left jaw is positioned 1/16″ left of center, where the blade is 1/8″ thick.  Assuming that the blade is 1/8″ thick and mounted dead vertical, the angles should be equal.

    A one-degree error shouldn’t produce a significantly unbalanced set of bevels.  More likely is that the blade wasn’t dead vertical or that you unconsciously applied more strokes or pressure to the side with the wider bevel.  It’s also possible that the bevels or angles were uneven to start with.  Just about all knives made in a production operation will show differences in angle, from side to side.  If the knife-maker’s fellow at the sharpening station keeps the bevel widths equal, but uses different angles, the edge will be off-center.  If he keeps the edge on center, the bevel widths will differ.  The WEPS gives you the opportunity to make it right.

    You can work the side with the narrower bevel until they match, or you can wait until the next sharpening to make the correction.  Keep in mind that regardless of these differences or their causes, the included angle will still be the same.  In other words; same level of sharpness.

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    #50483

    airscapes
    Participant
    • Topics: 10
    • Replies: 192

    Thanks Tcmeyer.  This clears up the picture a lot!   I assume that this lean condition only happens after you exceed 1/8″ thickness so thinker knives are held vertical?

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    #50488

    tcmeyer
    Participant
    • Topics: 33
    • Replies: 1852

    No, just because a blade is thick doesn’t mean that it’s necessarily leaning to the one side.  If the blade is leaning to either side, it simply means you haven’t done a very good job of clamping the blade.  Clay’s explanation simply says that even though the blade is vertical, the angles could be off if the thickness exceeds the 1/8″ design parameter.

    With the WE120 vise, the left jaw is always vertical.  You can use this to your advantage when the knife is “full flat ground” (FFG).  When clamped flat against the left jaw, you know that the blade is tilted to the left.  The amount of tilt is one half of the included grind angle between the two sides of the blade.  We can measure this angle with a digital angle cube and use the measurement when setting our rod positions.  My Delica, for example, measures at 3.8 degrees between sides.  This means the blade is tilting 1.9 degrees to the left if the blade is flat against the left jaw.  Deduct 1.9 degrees from the left setting and add it to the right and your bevels angles will be equal and centered.

    Instead of going through this to mount the blade perfectly, it’s easier to wrap the spine with some softer medium, like chamois or tape or such and simply try to hold the blade as vertical as you can as you tighten the lower (clamping) screw.  It works just fine and avoids the concern of using what some might think is a wonky set-up.

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    #50489

    MarcH
    Moderator
    • Topics: 58
    • Replies: 1884

    I have found sometimes trying to wrap the spine with a soft medium, in essence creating a shim, is easier said then done.  The shim mediums shift and compress under clamping pressure.  The shim is not even from side to side since we’re trying to offset the leftward lean.  At least using the correction factor although it’s wonky and a “fudge factor” is positive, tight and stable.

    Thank you Clay for the Gen 3 Vise innovation.  We now have an option so we longer have to deal with that situation.

    The Standard Vise set-up still has a valued place in Wicked Edge sharpening for very thick bladed cutting implements.

    Marc
    (MarcH's Rack-It)

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