testing the sharpness???

J

jester

Joined
Dec 27, 1999
Messages
118
Here is a question i have been thinking about a lot in the past, now i need your help, because you are the experts and i am pretty far from being an expert.

What is the toughest test for the sharpness of a knife-blade? I dont mean which test will completely destroy the blade, like bending it in a 90 degrees angle. I still want to be able to use the knife after the test!!!

We all know the shaving-your-arms-(and legs and chest a.s.o. if you have too many knives
smile.gif
)-test, but for example: is it possible to drop a sheet of paper on the blade and the paper gets cut through completely???

Which test can i perform to get the proof that my knife is far beyond razor-sharp?

Thanks for any help.
 
You want to know how to test that your blade is sharper than a razor? Ok - you asked this
smile.gif
:
Try free hanging toilet paper test (fhtpt)
wink.gif
but only push cuts are allowed
biggrin.gif
. I have not succeeded with razors edge... Last year there were many threads about sharpeness testing. In one (in november??) I introduced this demanding test.
wink.gif


Ok I searched it for you: http://www.bladeforums.com/ubb/Forum32/HTML/000282.html
[This message has been edited by Tommi (edited 01-18-2000).]

[This message has been edited by Tommi (edited 01-18-2000).]
 
Tommi,

Did anybody pass the test? if so, with what knife?
smile.gif


I just tried it, laughing while testing it, and it's next to impossible, even with the sharpest blade!
smile.gif
lol...

Dan
 
As soon as I get my next knife done and sharpened, I'll give the tp test a try. I get my blades so sharp, you can't even feel them cutting the hairs. I'll let you Forumites know how it goes, either way. Take care! Michael

------------------
"Always think of your fellow knife makers as partners in the search for the perfect blade, not as people trying to compete with you and your work!"

 
Here's a few of the tests I use for sharpness:

Slice a sheet of paper in the air as it drops.

Slice/push cut through cigarette paper (must cut in both directions-the paper has a "grain")

The old shaving hair test.

Putting a rubber band on the spine of the blade, stretching it and seeing if the blade will cut it when you let go.

Taking a piece of tissue or toilet paper, laying it flat and trying to make a complete cut without tearing.

All of these are hard tests, if your knife can do them, it's SHARP!

------------------
"Better to reign in Hell, than serve in Heav'n"
John Milton
There are only two types of people; those who understand this, and those who think they do.
 
In my opinion, the rubber band test wins the award for "Most Idiotic Sharpness Test Ever Devised". If the knife slips out of your hand, it could be slung directly towards your face.

Other ridiculously dangerous sharpness tests are the "Tongue Test" and "Hair Test".

One guy at a knife show said that a gentleman came up to his table and decided to test the sharpness of a knife by sticking it in his mouth. I've actually heard of this test before; you scrape the edge over your tongue to test the sharpness. Big surprise; the customer at the show spit out a mouthfull of blood after seriously cutting his tongue.

The hair test has been used by knife makers in Japan. You comb the knife through your hair and if the edge "sticks" to the hair, it's sharp. If the edge slides through the hair, it's dull. Needless to say, your head is the most important part of your body; blindly placing a sharp edge against it ain't too bright.

I just hope some genius doesn't come up with some kind of "Eye Test", or a "Femoral Artery Test", or (God forbid) the "Penis Test for Blade Sharpness".

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Cerulean

What the hammer? what the chain?
In what furnace was thy brain? - Blake
 
Re: the toilet paper sharpness test: use French toilet paper and it's easy. Wax paper is softer.
tongue.gif
 
Actually, I find the rubber band test rather fun. I worked on actually aiming with it. I was able to peg some candles.

I recently developed the inner ear test. What you do is, you stick the knife in your ear, and bring it back out. If there isn't any blood, the blade is either too short or too dull.

I can't help but wonder how sharp you really need your knife to be. I remember we once had a "My knife is so sharp..." thread. There were some concerning mosquitos' genitalia, others whose knives' cross-sections could not be seen, and many other ones. Good thread; look it up. I personally don't shave my arm hair for the simple reason that I don't want to look as if I tried to shave my arm, which would happen. Stick with these toilet paper/ wax paper tests.

Howie
 
Hello,

I put Shaving Edges on my Knives to,but mainly because thats what everyone expects on a knife.

But in Hard Use Reality, A slightly Toothier
Edge is a much better Performer, will outcut and Outwork a Polished Razor edge.

But the IRONY is tht if you provide this much better performing Edge,the customer doesnt think its sharp enough when he recives it...

Thats another area that Knife users need educated on by the maker.

My test is pretty simple,if it shaves hair
clean without Razor burn or stubble left ,both directions,its good to go!!

If not there is a burr on the edge or Improper edge Geometry was applied on the maker level.

my .02

See Ya,
Allen


------------------
Allen Blade
Spokane,WA USA

" It is Always Better to learn The RIGHT Way, Than to Continue Doing it WRONG "

My Custom Knives :
http://www.geocities.com/yosemite/meadows/1770/allenblade.html
 
I take a hair from my wifes hairbrush and hold it up. I the try to cut it into 1 inch up from my fingers.
 
Shaving arm hair is a good test. I have a bare left arm most of the time! The knife is BEYOND scary sharp if it will cut or at least pull hair when passed over the hair without touching the skin!
I think this is what Cerulean was getting at in part of his post above.
I have to agree with Allen about the finish of the edge also. It realy makes a difference in what you intend to use the knife for.
Neil

------------------
Talonite! Pictures are now up on my website!!
http://www.geocities.com/Eureka/Meeting/5520/index.html
 
I particularly like the rubber band test. I think if you can't grip a knife firmly enough to keep a rubber band from pulling it out of your hand, then survival of the fittest comes into play.

As far as hair testing, my dad used to sharpen his axe so well that he would use a little spit and shave hair from his leg (so his arm wouldn't look funny during business hours from shaved patches). Now that's very scary sharp, for such a heavy large blade. Did it all with hand files too, finished with a whet stone I believe.

Brandon
 
Just try the goosefeather test!
Siegfried , the ancient german hero of the "Niebelungen" myth took his sword "Nothung" and rammed it into a brook.Then he throwed some goosefeathers on the water and let them drift towards the blade.So the feather was cutted into half only by the flow of the water and the edge of his sword.

Try it !

Originally posted by jester:
Here is a question i have been thinking about a lot in the past, now i need your help, because you are the experts and i am pretty far from being an expert.

What is the toughest test for the sharpness of a knife-blade? I dont mean which test will completely destroy the blade, like bending it in a 90 degrees angle. I still want to be able to use the knife after the test!!!

We all know the shaving-your-arms-(and legs and chest a.s.o. if you have too many knives
smile.gif
)-test, but for example: is it possible to drop a sheet of paper on the blade and the paper gets cut through completely???

Which test can i perform to get the proof that my knife is far beyond razor-sharp?

Thanks for any help.
Click to expand...

 
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