"Sharpness" Tests, What do you use??

O

oldgranpa

Joined
Feb 12, 2004
Messages
44
What's your favorite "quicky" test for sharpness after you've got that "perfect" edge on your knife?

Do you use a tomatoe? Cucumber? Piece of paper along the edge? Some kind of rope? A strand of hair (whose)? Hair on your arm? Or what?

We all talk about sharpening methods and whose method is best. Most of us don't have microscopes to look at the blade or any other kind of instrument to measure sharpness, so don't include that, it's been discussed before. And, granted, the purpose for the blade can make a difference on whether it's polished or filed edge. Include the type of edge if you want.

But leave out searated blades. And just tell how you test sharpness for plain blades.

Curious, :rolleyes:
og........................(I haven't found the best test yet!!)
 
thumbnail. if it grabs its plenty sharp, if it scrapes, back to the v sticks.
 
Dragon scales. If the blade chops cleanly through a dragon scale without shredding fibers, it's sharp.

If you don't have dragon scales handy, you can touch the blade to a finger nail. If it catches, it's sharp. If it skids ... back to the Sharpmaker. I touch the blade at the ricasso and the belly and the tip. An edge tends to wear differently at different points.
 
I usually test on a sheet of paper, on the edge. If it will slice it cleanly, it's sharp. If it tears or snags, it's not. Mind you, this test does not favor very polished edges (2000 grit+). The fingernail test, IMO, simply doesn't require a blade to be very sharp. Or maybe my fingernails aren't hard enough :confused:
 
Fingernail.



From the bottom (thru the pad and bone)

If it sticks when it gets to the nail, it is SHARP.

:eek:
 
Sticky said:
thumbnail. if it grabs its plenty sharp, if it scrapes, back to the v sticks.
Click to expand...

My favorite method also. Recently my thumbnail has started to wear rather thin. I might have to join the Army so I can get the reconstructive surgery they are now promising---ahhh--a thumbnail transplant!! :D
 
I have tried all of the above and have settled on styrafoam peanuts, if an edge will slice super thin layers with out tearing then you know it is really sharp. A. G.
 
Thumbnail, followed by pushcutting through old business cards. My professional title changed about 4 months after I had ordered a thousand business cards, so I have a giant box of them sitting on my workbench. I can quickly get a sense for how sharp an edge is by how much effort it takes to slice through the card. So far the sharpest I've seen is the serrated portion of my 556 mini-grip.

The styrofoam peanut thing sounds interesting though.
 
I actually use a couple different methods. I first see if the blade will shave hair from my forearm in the same manner as Esav (ricasso, belly, tip), then I hold a cotton towel fairly tight (but not too tight) and pull the blade across the edge of the towel with only the knife's weight for pressure to see if it cuts aggressively. If it does both decently, it's sharp enough. I do both because I've noticed (as I'm sure many of you have) that a shaving sharp knife can kinda' suck at cutting fabrics, etc. The opposite is true, too. So, I just try to get to that happy medium.
 
My primary test is to feel the drag on my fingerprint ridges when I scrape the edge over my thumb or finger tips. Next I shave a little arm hair. Then I move on to shaving some facial hair. I thin most edges down so I don't have to worry much about macro performance. If the blade is on the thick side I test how cleanly I can slice through the middle of a cardboard box.
 
Dang...And I thought that I'd be the only one to use my thumb-nail to test the sharpness of my knives.:).
 
Many years ago there was an article in the American Hunter on sharpening. The author suggested taking a magazine page & folding the edge about 1/2 of an inch. Then try to cut the paper down. If the edge is very sharp it will cut easily without crumpling the paper. Thru experimentation, I have found that only the sharpest edges will cut the paper without sawing.
 
I usually shave paper, but if I want to really show off, I'll dangle a hair and slice through it. :eek:

But then I show off by honing a knife off on a flourescent light bulb. :D

Pam
 
My first test is my educated thumb - if it feels sharp to me on to the next test and that is skiving the edge of soft leather such as chamois, buckskin etc if it takes off a piece cleanly its sharp.
 
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