How Do You Test Knife Sharpness?

Oct 3, 1998
I never had a problem with this until recently. I'd either shave hair off my arm or shave a fingernail. I would take my serrated blades to the mall and have them sharpened at the knife store. Then I bought a Sharpmaker and figured out how to sharpen serrated blades. Shaving hair off my arm doesn't work with a serrated blade. Well, I haven't really tried it but I don't think it will work. So what do you people do to test your blades after you sharpen them (besides buying more knives)?
I test my knives out by cutting stuff like rope and cardboard. I've never tried shaving hairs off my arm because, first of all, your going to look really dumb a place on your arm with no arm hair. And second and more importantly, I use my knives for more than grooming my arm, I open boxs, food, cut tape, cardboard etc. so I want to know how well it can cut those things and not my hair.

I have no hair on my left arm, therefor according to Adamantium I am dumb

Actually the shaving hair test is most used simply because it is the most visually striking. When I sharpen a knife for someone I usually shave some hair in front of them to show the quality of the work I just preformed. Is this a true test? Duh NO! But it is a test none the less and people use it all the time. I just don't usually have 1" manilla rope "hangin around".

Maybe Lynn Thompson has some hanging around the office.

Best Regards,
Mike Turber
I usually run the edge along my thumb and see how it bites in. If I am wanting a smooth edge, like for shaving, after I test on the thumb pad, I run the edge along the edge of my fingernail to see how smooth the edge is. BTW, be VERY careful when testing sharpness on the thumb, it takes a little while to learn just how much it is biting. It also helps if your thumbs and fingers are calloused.

Spencer Stewart
I always test my results on a piece of 20-lb. laser paper. It is 50% fibrous, due to the cotton content, and seems a consistent (albeit not necessarily valid) test of the degree of sharpness I'm looking to achieve.

If it glides easily through the paper, I'm satisfied. If the edge grabs and scratches its way through the paper, I keep sharpening.
I'm stupid also.

My left arm is hairless.

Generaly I figure if it will shave hair,
its sharp enough for me to cut myself really good with, and thats sharp enough.

Serations are a mystery to me.

Why does Frank have hair on his finger nails?

" I'd either shave hair off my arm or shave a fingernail"

how do your palms look frank heheheh

i to, am a one hairless armed dumbie(spelling) idiot

[This message has been edited by txlazer (edited 10-12-98).]
The obvious goal is to get it so sharp the hairs jump away in terror without actually touching steel.

Note: I said *goal*...

I have to admit to having Knife Collector's Mange also, on both arms.

Frank's question was actually about testing serrated blade sharpness, I think. The fact is, I don't have a really great test for serrated blades. I just feel the blade with my thumb.


Arm hair or thumb, (thumb Does work for serrations). After you've sharpened for awhile YOU KNOW. I'm also like Jim March, I want the arm hair to "jump" off my arm.
Well, I guess I'm really in trouble. When I sharpen several knives and run out of hair on my arms, I shave the hair on my legs
Does that mean something??

Testing serrations? I usually cut cardboard or reinforced packing tape. Hey Dex, any suggestions?
Yeah, I was only talking about serrated blades. Those Spyderco serrations look like they'd gouge the *&#$ out of an arm.
When I want to test the sharpness on a just finished blade I give it to my wife to shave her legs with.That way she gets rid of her hair and I get to keep mine.Just kidding though she never would go along with that idea LOL.
My wife and I were 50 miles from home heading
to "big friendly D" when I heard her shriek
in sheer panic that she had missed a spot
on her fresh shaven legs.I whipped out a
Stryker and said "use this" .One swipe and the problem was solved.Knife saves man & women in desperate situation once again.
The only test for serrated blades i have ever been able to use successfully is the "rip the hell out of cardboard" test. It is an extremely scientific test and only professional knifenuts should try this.

You take a 200lb test cardboard box a attack it. Make long slices and try to get the serrations to not hang up. The paper should not roll over and prevent further slashing. If you saw the Cold Steel video you would have seen Lynn Thompson doing a similar test.

Best Regards,
Mike Turber
SDMatteson - Then your wife started singing "Did I Shave My Legs With This?" Heh heh. couldn't resist

For a serrated blade I use the pen test. It seems to work for me. You take a pen and hold it in the left hand angleing down at about 75 degrees. Then with the right hand drop the blade down on it, only use the wieght of the blade for force. If it sticks and dose not slide off it should be sharp. If it slides do some more work on it.
Gee, you guys with your hairless arms really break my heart! I'm left with only "eyebrows" over my ears... damn folicles just up and migrated south on me! No knife testing there
! As Marcus Aurillieus Arnheiter (SIC?)(of the infamous Arnheiter affair during 'Nam) once remarked to me "Son, that's a fine nautical looking beard you have there." Then again a warrent of my acquaintance counselled that the condition was brought about by too many U-turns under the sheets! I'll never tell <hehehehehehe>!

-={Grey Beard]=-
Heel of the palm. I set the knife at an acute angle and test the bite using just the weight of the blade.
Kids, do not try this at home.
Rich Lucibella

[This message has been edited by Rich (edited 10-12-98).]
Geez, I guess that I am not alone... But I do it different... Still dumbly.

I only use the back of my left hand. It is rare to see the backs of both of my hands at the same time. Never had a comment.

Now when I used to use my arms, I heard about it all the time. Try it, it may make you mor smarterer than b4re.

PS - Watch out for veins...