Hanging Paper Test?

UltraSteele

UltraSteele

Joined
Dec 12, 2002
Messages
163
I want to write up some of my experiences/reviews of some knives, but one "test" eludes my understanding.

Many magazines talk of a "hanging paper" test or "Hanging thread/paper" test. I understand this is a test of egde sharpness/geometry, but how is it DONE?

Do I just take a hangning sheet and slash it? Cut it slowly?

Can anyone tell me what I'm looking for?

Thanx
ChernoBill
 
Yes, you would tie a paper to a string and slash into the paper.
Slashing downward is kind of cheating.
I would be very surprised if any knife can cut a hanging piece of paper when pressed against it slowly.
 
Beyond the hanging paper test is my personal favorite.....The Hanging Toilet Paper Test.

The idea is to take a length (4 - 5 sheets or so of the softest/fluffiest TP (I prefer Charmin) and while hanging this sheet from your non-dominant hand make a quick downward cut into and through the lowest 2 sheets all the way out of the bottom.

If you manage to cut through the TP without tearing it while making a clean smooth pass and without tearing any part of any sheet along a perforation then you got one really sharp knife.

It is acheivable but it does take some work. I can do this with my Marble's 7" (10"OAL) Trailmaker partly because I can get this sucker really sharp by leather honing the convex ground blade. No swoosh here but rather a wiff sound. Swwweeettt!!!:D
Now what was amazing to me was that my straight out of the box my SERE 2000 performed this test perfectly with it's factory sharpened edge. In my experience this is very rare to see . I did later dull the SERE's blade by trying to cut through a plastic-ish tip of a Blistex tube. I couldn't believe this happened because I've cut so many really tough items with this knife and then it goes and meets it's match on a tiny tube of Blistex. I mean what's this tube made of anyway? That Blistex tube was like Kryptonite to my Super SERE.:eek: Go figure? After I resharpened the SERE I did the free hanging TP test again and it failed miserably yet still shaved hairs. Hmmmmmm....
This then left me to go to the leather hone. After honing it performed only marginally better. It will almost do the free hanging TP as good as new but yet it's still not the same as it was right out of the factory box.
Another knife that I experiment on regularly is a Puma Protec with 440C blade. Out of the box it never cut good. I free handed on Arkansas stones but that did nothing. Then I used my Sharpmaker and by using both sets of rods 3 times (using all corners and flats) I was able to rip through the TP. Ahhh.....results.:) Then I went to the leather hone and whallah!!! "Wiff" sound again.

So, I'm not sure what I can deduct from all this other than some dull, out of box, blades (good and not so good steel) can sharpen up sup real nice while some sharp ,out of box, blades (good and not so good steels) can never be brought back as good as the original factory edge. Of coarse my sharpening skills could have a lot to do with it too.;)
Plus, some blades seem to work with better in the free hanging TP test with a coarser grind rather than a polished grind and vice-versa. I know there's a lot more to all this when you start talking scientifically but I know the patterns that I see myself.

Either way, try this test on a few of your knives and see if they're as sharp as you actually think they are. Compare this test with the results from other tests. I think you'll be surprised.

Just my 2 cents.....

--The Raptor--
 
Be carefull when slashing UP. Once I tried this with my Endura. Don't remember what had happened to paper, but I haven't even noticed loss of nice figerprint's part on my thumb on the left. What made me tonotice that something is wrong was the hit on the nail of another finger. Felt no pain. Also a result :(
 
Thank you all!

Raptor- thanks for the great input. Python- sorry to hear about your thumb! At least it wasn't on your cutting hand, eh?

Please anyone else who has two cents, put them in. I'd like to have the right info so I can represent myslef and my views as accurately as possible.

Cheers all!
 
Take a piece of collage rule notee book paper and cut it into strips that are two lines wide and half the width of the page long. Now tie a #9 (small) paper clip to the middle of a string about four feet long. tie the ends of the string to whatever so that the paper clip is hanging at the botton of a vee at the level you are comfortable cutting at. Put a strip of paper in the clip and cut it in two without pulling it out of the paper clip. When you can do this then do it with a whole piece of paper and keep your cut between two lines on the paper. You can also set the edge of the knife on the paper and just slice off a piece if your knife is really sharp.
 
One test that is more skill as much as sharpness is to hold a sheet of paper, knife at the ready, drop the paper and as it free falls to the ground, bring the knife into action and slice the paper in half, I was able to easily do this with my Spyderco large Calypso, amazingly sharp knife! But again, be extra careful when slicing through the air as people could walk up near you and not expect it! or you could hit your other arm before you could stop the travel. But once you do it, it's pretty darn cool to see, if you make a miss hit, it won't go all the way through the sheet, so practice makes perfect and the edge has to be just so....

Good slicing!
G2
 
I have done many of these "tests" from time to time. They are interesting and fun, however they are very problematic for use in trying to guage and understand sharpness because they are very dependant on the user skill level and various blade aspects which influence cutting ability such as balance, edge curvature and geometry .

If you want to understand and evaluate sharpness specifically, get a cheap magnifier from radio shack (10x-20x cost a few dollars) a simple spring scale, and a ruler. To check for push cutting sharpness, make a loop of light thread, put it in the hook on the spring scale, and press down cutting it with the knife. The lower the weight needed to make the cut the sharper the blade.

To test the slicing aggression sharpness, mark out the blade length in small intervals, like 0.25 cm or 1/16", tie a weight to one end of some rope like 1/4" poly (500-1000), put the knife under the rope, raise the blade up to take the tension, letting the weight hang free on one side and you holding the rope in the other hand, draw the knife until the rope is cut using the length of blade required as a measure of sharpness.

You will note as you try these tests, that it is possible to increase performance in one area and even decrease it in another. After doing the cutting look at the edge under magnification and get an understanding for how the edge is doing the cutting - where the performances comes from.

-Cliff
 
I did this with a free hanging piece of A4 photocopier paper, using my Scott Slobodian tanto. The piece of paper was cut neatly. I can do this about one in three.
this is much more of a skill test rather than a sharpness test. There's a guy, a japanese tameshigiri master, who can cut with a sword a single rolled up newspaper sheet. But again, asked if his was a particularly sharp sword, he answered that it's just a matter of skill, as long as the sword (knife) is well sharpened.
 
Wow all, thanks!

Thanks to Cliif Stamp as well. I love have a more objective test system. Great ideas. But Cliff, in the "slicing aggression" test, how much weight do you mean? 1 lbs or 50?

Cheers!
Bill
 
My fave test to do with my Lum Chinese was to dice (one handed obviously) an apple while it was still on the tree. I thought it was really neat to see the apple chunks fly!
Matt
 
UltraSteele :

in the "slicing aggression" test, how much weight do you mean?
Click to expand...

Something small, about 1000 g is about maxium for 1/4" poly, if the knife can not slice the rope under that level of tension it has little aggression. Verp aggressive knive that are well sharpened can still make complete cuts at 500g (about a pound).

-Cliff
 
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