Sharpness Test

S

Sam1

Joined
Jan 26, 2001
Messages
43
Well.......I got my CUDA (plain spearpoint thank you) in the mail yesterday and after about an hour I had already made the end of my thumb sore opening it (gotta build up that CUDA callous). Let me tell you, this hummer came from the factory with a pretty darn good edge on it. And of course being the dope that I am I just had to run my thumb over the edge. And of course it bit me!
rolleyes.gif

As my delayed thought processes kicked in I thought to myself "just how are you really supposed to test sharpness anyway?" Since there appears to be no future in my current testing method, I would appreciate input.
 
Some simple tests:

1. Run the edge through the hair on your arm, about 1/8th" above the skin. A good edge will grab and cut the hair.

2. Try to fillet a piece of paper. A good edge will do this easily.

3. Shave hairs from the back of your hand.

4. Drop a piece of silk on the edge. A super sharp blade should cut the silk.

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It's not the pace of life that concerns me, It's the sudden stop at the end.
 
For showing off how sharp you can get a knife (I use a sharpmaker): take a hair about 2 inches long in your left hand, holding it between your thumb and index finger. Using your right hand, bring the knife down sharply, cutting the hair in half. I only bother to get my dress knives this sharp - after you cut anything with it, the burr goes away and you can't do it any more. If you try this, please be careful not to cut your thumb off!
 
Place the knife open on a table with the edge facing up. Wait a week or so.

With a microscope, examine the dust on the table on either side of the blade. You should clearly see that pieces of dust have been cut in half as they fell on the edge.

FermiLab likes to borrow my AFCK. They mount it in the beam of their particle accellerator and use it to cut atoms apart. It's much more affective than the old atom-smashing bombarding techniques they used to use. It gives a cleaner cut so they can more clearly find the subatomic particles.


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Chuck
Balisongs -- because it don't mean a thing if it ain't got that swing!
http://www.balisongcollector.com
 
Sam, touch the edge to a fingernail, lightly. Now move it across the nail. If it is really sharp, it will "track" across, instead of sliding off.

This is also a good way to test if the edge near the tip is as sharp as the edge near the handle, since careless sharpening may not do a thorough job near the tip.

Don't use the same nail all the time, or it will look like an old roof shingle, like my left thumbnail.
 
Thanks everyone, Sgtmike88 especially! Now not only do I have a bandaid on my thumb, I have bald spots on the back of my hand and arms.
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Hmmm, maybe I should give that thumbnail thing a try.....
 
I use the paper towel test. Much like cutting paper but even a knife that will slice paper smoothly will only cut a paper towel if its really sharp. If its not it tears and/or rips while cutting. A REALLY sharp knife will allow you to cut through the paper towel very fast without ripping it.
 
Step 1.Place your knife in the glove compartment of your truck with a potato.

Step 2. Drive down 5 miles of bumpy road.

Step 3. Examine potato.

If potato is whole, discard knife.

If you have home fries, send it to a pro to be re-ground

Mickey D's fries means you're getting there

Hash browns is a decent working edge.

Mashed potatoes is as good as it can ever get.

biggrin.gif


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Tráceme no sin la razón, envoltura mi no sin honor
 
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