What angle to sharpen?

[Scott J.]

Like some others I sharpen by hand so I don’t know the exact angle but I make it as thin as I can without much risk of scratching the full blade but it’s certainly less than 20 degrees. I’m not sure anyone has really given an opinion about whether to re-profile the blade. I think there are times when you do and times when you don’t. In this situation and any time you are using a larger angle than factory I’d say no to re-profiling if you are sharpening to a smaller angle than factory then I’d say re-profiling is a must. I am including terrible drawings to show why I believe this. Picture 1 shows the original edge and the sharpening angle, say a 15 degree original edge with a 20 degree new edge. Picture 2 shows the new edge if you fully re-profile it. Picture 3 shows the edge if you just sharpen it at the new angle without re-profiling, this edge would certainly cut better that 2. Picture 4 shows the blade and the intended new angle that smaller than the old, say going from 20 degrees to 15 degrees. In order to get the new angle all the way to the edge you have to fully re-profile to even sharpen the edge. Hopefully this wasn’t just me rambling.
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Excellent diagrams, thanks!!
So, would #3 be similar to putting a microbevel on a blade?

 

[jsdistin]

Excellent diagrams, thanks!!
So, would #3 be similar to putting a microbevel on a blade?

Yes it would be, and that would be the one I would go for if I was putting a wider than factory edge on a knife. I would sharpen just enough to put a new edge on it and no more. Otherwise you’re taking away material that is unnecessary and making it more difficult for whatever you’re cutting to pass by the blade as you go through it.