Overgrind versus uneven grind

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milkbaby

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I got a new knife that wasn't as sharp as I like and was wedging in and cracking carrots, so I tried my hand at thinning a bit on diamond plate and waterstone then sharpened on waterstones.

There is a portion of the edge where I can see light shining through when in contact with the cutting board, and when I sight down the face of the blade and move it around in the light, I can see a portion of the grind dips down. And this is also where the edge is frowning a teeny bit. There is definitely a low spot in the grind on one side but can't tell exactly how deep it is. Deep enough to see by eye at least.

Do you only get a bad unrepairable hole in the edge when the grind goes past the centerline of the knife? By centerline, I mean the plane down the middle that runs all along the spine through to the edge, like if you bisected a double bevel knife blade into two single bevel blades.

Maybe I'm not thinking the geometry though carefully, but if it's an uneven grind that doesn't pass through the centerline, theoretically I could thin the entire grind even by hand on a flat diamond plate and have no issues with the edge profile frowning? How badly would this wear down my diamond plate? I only have a DMT extra coarse (220? grit not the xxc 140? grit) which I use as a stone flattener.

Since the small frowning section is not bad, I'm contemplating just sharpening as needed until I figure out whether it's fixable or not. On the other hand, this knife is kind of a fatso that I wouldn't mind thinning.
 
Make sure that whatever you are testing a flat edge profile against is itself flat (machinists square for example) - "light shining through" can be 1/100mm or 1mm, and a cutting board is suspect at that scale. Also, make sure there are no residual burrs when doing that kind of test (especially to plan repairs).
 
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