Confirming Sharpness

M

microtech85

Joined
Dec 1, 2015
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Hello, I am interested to know how many of you test to confirm you have sharpened your knife to your satisfaction. I personally will test cutting through a paper towel, a piece of printer paper, then finally how easily the hair pops off my arm. If I can shave my face, then it is as good as I can need. I can get mine that sharp just using the spyderco 2x8 inch fine stone. I sharpen once a month with an "s35vn" blade on the spyderco native 5. How do you test?
 
I test for bite by pulling my thumb across the blade.

After stropping I strip-cut phone book paper or newsprint to test sharpness.
 
Shaving electrons off molecules to produce ions:D. (Actually, if it'll pop arm hair it's sharp enough.)
 
slicing or push cutting newsprint paper on any side in any direction, straight or curved lines, fast or slow, without feeling any dragging or tearing. I have not achieved hair splitting yet.
 
I use phone book paper for slicing & push cutting tests. I also check for smoothness all along the blade when I'm cutting. Want to make sure the edge doesn't hang up or tear the paper. Most of my "sharpening" is actually touching up done on loaded and bare strops. Any real sharpening that needs to be done is done on a Sharpmaker with the M and F rods.
 
Good results here from free-hand near parallel diagonal strokes on Dia-Sharp Extra-coarse, then finishing with either worn Dia-Sharp Coarse or a medium stone to break a wire edge, sometimes rubbing at near 90 degrees to break the darned thing. Check with nail top for wire edge on both sides. Avoid any rocking as you stroke, and use the shadow under the edge from a strong artificial light, usually not daylight.

12 degrees per side on a thin 0.020" V-edge and chopping wood with a 1/4" stock 9"+ blade works well, though a lot of steels show damage (not Randall 440B or Lile D-2 so far, maybe because the -dull- initial bevel is hand applied and doesn't harm the apex): Usually this is because the edge is power-applied, and this may go away after a few cold sharpening.

Gaston
 
It should easily catch arm hair with very little effort. I don't actually shave arm hair off because I don't want bald spots all over my arms.
 
Shaving hair demonstrates nothing, and I use now the phonebook paper plus a check on the flatness of the edge sides at the 12 degree per side angle. Not rocking during sharpening is key for edge side flatness. Phonebook paper should be cut vertically free-hanging easily, the smoother and less tearing noise the better.

Hardest part is using the nail top rubbing to find nail shavings and exterminate wire edges on both sides... Wire edges are good at hiding themselves, and often getting rid of them will dull your knife by rounding off the V's flat sides, setting you back to square one...

Gaston
 
I use phone book paper to determine if my edge is satisfactory. If it'll cut under blade weight alone, and is able to cut very thin strips I call it good. Every now and then I'll see if it'll pop hairs but you run out of hair really quick lol.

If it'll whittle hair it's beyond good enough for me.

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how do you even whittle hair? I have to try it, I just test with a piece of paper cutting in every direction
 
Hold the blade stationary edge up and take a hair and run it down across the edge. If it's sharp enough it'll catch the hair and feather a strip off as you pull down on the hair...sometimes a knife is to sharp and will just cut the hair at the lightest pressure or the hanging hair test.
 
Honestly a hair whittling edge isn't practical in most situations. On an edc knife imo that sharp of an edge deteriorates allot faster than a shaving sharp edge.

I only did this one as a bet from a work sharp hater I know who told me there was no way it could produce a hair whittling edge....needless to say I'm $50 richer and he doesn't talk trash about the work sharp anymore when I'm around lol.
 
PB paper, and your fingers (after you've been sharpening for a while, and know what you're looking for, what an edge feels like to your finger tips is the best way to tell if you are where you want to be)
 
Gaston444 said:
........Hardest part is using the nail top rubbing to find nail shavings and exterminate wire edges on both sides... Wire edges are good at hiding themselves, and often getting rid of them will dull your knife by rounding off the V's flat sides, setting you back to square one.....
Click to expand...

Finally, someone said it.....

JR88FAN said:
PB paper, and your fingers (after you've been sharpening for a while, and know what you're looking for, what an edge feels like to your finger tips is the best way to tell if you are where you want to be)
Click to expand...

Yeah, same here. Been doing that since I was a kid....
 
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