How do you measure sharpness?

Thanks for all of the responses. The collective knowledge of this community is amazing. As soon as I get home I'm going to start testing the blades.
 
I do the 'nail trick' periodically between stones to ensure I've been getting a good scratch pattern, and I do a generic newspaper-cut test once I'm done sharpening. If I'm trying to get a little something extra out of my edge, I'll try shaving my face with it once I think it's up to snuff, but I don't generally do that with my work knives...
 
me2 said:
Getting an SEM is a little complicated. WTF do you mean?
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I think he is saying that using a scanning electron microscope to try and predict edge sharpness is a pretty absurd recommendation to test edge sharpness on a knife forum.

Maybe if this was the physics nerd website but not your run of the mill knife nut.
 
a microscope that high powered is totally unnecessary.

your average college chem/bio lab's microscopes are however, quite handy and relatively inexpensive all things considered. they will shed quite a bit of light on how good your edge actually is.
 
On my users, if it is sharp enough to perform it's intended task, it is sharp enough
 
Of course its unnecessary, but he asked what ways are there to measure sharpness. This is the only way I know of to get an actual dimension of an edge. All the other methods I mention will just tell you this knife is sharper than it was, or than another knife. There are articles on line that will give an idea of what edge dimension is needed for common cutting tricks and certain tasks.
 
See the edge under the direct sunlight.
This gives me an idea which part of the edge is how much damaged.
 
I check my knife under light to look for flats. If I see flats I hit the strop. If I see flats still Ill move up to the sandpaper. After that Ill strop again, double check in light to make sure its perfect. After all that ill test the knife on my arm hair. If it shaves em off easy, then its good enough for my tasks:)
 
fujita yuji said:
See the edge under the direct sunlight.
This gives me an idea which part of the edge is how much damaged.
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Please forgive the slight hijack.... :o

Fujita-san, when you were still living in the Kyoto area you posted the name of a very large knife shop, I believe, might have been around Suita or Ibaraki. Do you recall the name of this shop? I'd like to find it. Thanks

Stitchawl
 
stitchawl said:
Am I the only one who drops a silk scarf onto the blade to see if its own weight will cause it to cleave? I saw Saladin do this in a movie and always thought his method was better than King Richards... :cool:

Stitchawl
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I prefer to simply pluck a single strand from a spider web and drop it onto the blade. It should cleave just before its full weight falls on the blade...that is when I switch to the next grit and put a polish on.

Seriously, it depends on the blade. I carry my H-1 most days and sharpen it (touch it up) every other day perhaps. I do not go crazy most of the time and push back from the table after 2-5 minutes of honing and the knife is very sharp but will not whittle hair.

On my lighter use blade (S30V) that I carry casually (not for hard work)...I will polish that one to the best of my abilities and it will easily whittle hair, shave letters off newspaper, cut free hanging TP, and just about any other test of ridiculousness I can find on youtube.
 
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