Yup, all kinds of "sharp" out there.
As many of you know, my life has somehow evolved into the quest for the utltimate edge. (not sure how that happened BTW).
As a kid free-hand sharpening knives, the goal was simply to be able to shave hair off my arm with the grain. That was plenty good for many years, and still is to some extent but, always looking for a bit more. Next challenge was to get the blade sharp enough to shave against the grain. That still is my standard. If the blade will shave hair in any direction, it's pretty darn sharp.
Then I saw the hair whittling challenge on bladeforums. That's where you take one individual hair and carefully whittle tiny curls up along the edge of the hair... without cutting through it. That took some time to achieve!
Now if you guys want to drive yourselves nuts like I do, the hair whittling is a good time killer and so is cutting hanging plasic wrap. Pull a foot or so of plastic wrap off the roll but, dont cut it, just let it hang vertical. Then poke your blade through near the top and with no sawing motion, just straight down pressure, see if you can cleanly slice through it.
Soilarch has mentioned another great sharpness test- If you can get a blade to cut hair from your arm
without touching your skin... well you just can't get much sharper than that!
Shaving sharp as most of us think of it, is really pretty subjective. Fine hair is harder to shave than heavy hair, and long hair is easier to shave than stubble etc. so "shaving sharp" covers alot of ground. I have found a sharpness test that anyone can do and the results are accurate and reliable:
Turkey wing or tail feathers. Sharpen your blade and while holding the feather by the base of the quill, see how far away from the quill you can get and still cut off sections of the feather. A fairly dull blade will cut right against the quill but, the farther you move away from the quill the sharper the blade needs to be cut the fibers before they flex away from the blade. When you can cut the very tips off...
Ron