How do you like to test for sharpness?

Emre

Emre

Joined
Nov 15, 2006
Messages
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Like the title says, I'm wondering what techniques/methods you guys are using to test sharpness.

I find cutting paper too easy: just about any knife can do it. Shaving hair off your arm? That's nice...but I'm not crazy about walking around with bald spots on my arms like a mangy dog.

Lately, I've been doing the fingernail stick test, followed by shaving some wood. I'll make little mini fuzz sticks on chopsticks or even toothpicks. Here's an example using one of my Dozier folders on the end of a bamboo chopstick:



Those are some pretty tight curls for such a big knife. Penny for scale:



This is actually harder than it looks. Bamboo is fibrous and inconsistent. Very easy to splinter, break, or hack off a chunk. If I can cut really fine, smooth curls with ease on a brittle bamboo chopstick or toothpick, then I know I'm good.

How about you?
 
You got alot of chopsticks I hope.

I usually use the finger nail thing when I am sharpening to make sure my apex of my edge is not leaning one way or another. If it is even then it sticks if I move it in either direction. If it sticks one way and slides the other then I need to even it out.

After that I use paper, but thin paper. I find the thicker paper is easier to slice.
 
I feel the edge with my fingers, zero pressure, if it bites, success, if it feels granular, burr, if it feels smooth, overpolished/rounded, not fully apexed or folded burr.

that's what you have to do when you run out of arm hair and paper :D
 
I come off the Shapton Pro 15,000 and bring the edge near my arm . . . if the hairs on my arm pull them selves up and leap off my arm before the edge gets to 'em THEN the edge is pretty sharp. If they wait in defiance with a stiff upper lip to be mown down I go back to the stone for another couple of super light passes.

Simple.
 
I usually grab some carbon paper (the super thin receipt paper) and test on that. If i can push cut that kind of paper, its sharp enough for me
 
Try to fillet the letters off a page of news paper or catch arm hair above the skin.
 
I use the Finger test and slicing phone book paper.

Shaving wood is not a very good test. A blade that won't slice phone book paper will still curl wood.
 
DeadboxHero said:
I feel the edge with my fingers, zero pressure, if it bites, success, if it feels granular, burr, if it feels smooth, overpolished/rounded, not fully apexed or folded burr.

that's what you have to do when you run out of arm hair and paper :D
Click to expand...


I do the same. Finger tips can tell a lot about the edge status.


Miso
 
Lapedog said:
You got alot of chopsticks I hope...I use paper, but thin paper. I find the thicker paper is easier to slice.
Click to expand...
With all the sushi and Chinese take-out places around here, I'm pretty flush with chopsticks.

I'll test on paper, but it's generally too easy. Receipt paper isn't bad though: thin and flimsy enough to tear if the knife is a bit dull.
 
I like to scrape my thumbnail. Judging how well it grabs the nail. Sharp knives will not slip at all. Dull knives will not bite as much or even slide off.
 
newspaper
Paracord
Polystyrene insulation sheets (can be cut really really thin)
leg and arm hair, if any left
 
Loosely bend a magazine page over on itself lengthwise and slice at the bent apex. If it cuts in smoothly, I am alright.

That being said, if I am at work, I will just look to shave a dmall patch of hair from my arm or slice hamburger patty paper (comparable to receipt paper, possibly thinner, and waxed on one side).
 
In the following order:
- Feeling with finger tips
- Slicing flat piece of phonebook paper, both straight and curly, fast and slow
- Slice single roll of phonebook paper (this is basically what NJBill described above)
- Splitting hair
- Staring at the edge to see if my eyes bleeding (not happened yet)
 
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