Best way to test sharpness on a knife?

When I first got into blades, I would test the sharpness by nicking the skin on my arm, if the blade cut the skin easily, it would pass the test, the scars are completely gone, but back then if I was in bright light my arms looked like they were dragged across a thousand thorn bushes, surprisingly, no one ever commented, but they were very visible.
Nowadays I just get computer paper and slice, and to test the coarseness, I get a piece of paracord, then try sawing through it with little pressure.

Actually when I shine a light on my arm you can clearly see a bunch of scars, nevermind, I really do need glasses
 
I'm not satisfied until my blade can cut a dangling participle.

Actually I just feel it with my thumb or just cut something. My arms were bald for years and my wife accused me of manscaping! ME! Well, I had to cut that shit out...
 
I don't actually shave the hair on my arm but just push the edge down the top of it. Don't touch skin, just hair. If it catches, that means I've reached my happy sharpness place
 
Cut whatever you usually cut.

my work knives, mainly cut food, so I'll test on rolled wax paper or thin magazine paper. There should be no snag and should be quiet.

My folders, cut through boxes and plastic ties, so I'll test on cardboard, if it glides like printer paper I'm good.

Outdoor knives, as long as it slices paper I'm OK with it.
 
Another vote for push cutting phone book paper with ease. I push it slowly. Truthfully, even slowly slicing it will be a good test.
 
I used to cut magazines and printer paper and hair and receipts and napkins and toilet paper...to the point that my girlfriend would hide any paper products from me. :). But I always checked the edge with my thumb before cutting those things. So now I have a pretty fine tuned thumb and can skip the paper slicing. I can feel how sharp and how refined my edge is with just my thumb. I can even tell when it's reached "hanging hair" level. Be that as it may, I still have no hair on my left arm. :rolleyes:
 
JOELSM said:
Heroine addicts have track marks...knife junkies have these:

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Eventually the knife junkie moves to the leg...sorta like a heroine junkie.
Click to expand...
Agreed. Lol. My left arm is almost completely naked from doing that. Leg hair is too thick and not enough of a test. :D
 
LIke others have said; newspaper, phone book paper, and arm/leg hair. (I use leg hair to hide my bald spots ;) )

Also important to note...thumb testing the edge isn't always accurate. I've had blades that were so sharp and smooth on the edge after I was done sharpening them that I thought it wasnt as sharp as it should be but testing it out showed it to be an incredible cutting edge. This also kinda scared me because of how scary sharp it was. Popping off hairs with no pressure applied.

If you have a sharpening system and you're worried about the edge not being refined or worried about the edge rolling. Test it in paper then cardboard then paper again. Then if you want go back and polish/touch up the edge.
 
There are quite a few ways that you can try but all have their shortcomings.
The paper test is a goot one, except if you have a knife with a lot of metal behind the edge, it wouldn't be very good.

The shaving test is a pretty good one...but you can cut yourself.
You can always use some rope (but you're dulling your edge for that)
blah blah blah

At the end of the day, if a knife can shave my fingernail enamel with no pressure, it is what I call a "usuable" edge to it since it will be able to handle almost every task given to it unless you need that scaple sharp edge
 
Shaving and paper is fine but I like to feel the edge cling to my skin when I touch it with a finger.
 
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