I don’t think there’s a need to go finer than 2 micron, unless your purpose is to achieve something more spiritual. I don’t think there’s much to be gained, other than increasing the level of polish a bit. With my 50X USB ‘scope, I can’t see a difference.
The hair-whittling test doesn’t work very well for me, as the hair I have left is really fine. I can ask my wife for one of hers, but she’d get sick of that pretty quick. One thing I’ve noticed that is a pretty good indicator of sharpness is demonstrated when slicing open an envelope. Not so much the ease of making the cut, but by the sound produced. Really sharp knives make very little noise.
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