Sharpness Testing???

mykulmorris

mykulmorris

Joined
Jul 8, 2007
Messages
1,690
I know this might sound silly but how do you guys test your edges for sharpness? The 'paper' cutting isn't good enuf for me and I'm starting to run out of hair on my arms(my wife laughes at me because of the bald spots)... Has this been covered somewhere before?
-Michael
 
I ran outta arm hair long ago!! switch to the legs :) i may regret doing so come summer..,but right now its cold :)
 
i'm in about the same boat as you two with armhair. for some reason my arm doesnt seem to have as much hair as it did a few years ago. if i'm lucky someone with hairy arms stops by if i'm sharpening knives and i have them test the edges :D.
 
yep leg hair!
or cigarette rolling paper, though personally i haven't been able to get one to that yet!
 
It depends on the knife, too. I have a Crowell/Barker that slices newsprint just fine and will shave leg hair clean if you're careful. But since I beat the snot out of it, that's plenty sharp for me. The edge holds up to plenty of chopping.
 
I don't actually shave bald, so I don't get the bald legs so bad. I float the blade 1/4" above the skin and knock the hairs off mid hair. If it doesn't grab any, it isn't done. If it pops a bunch of them, it is good. If it levels the field like a lawn mower, I did good.

Just for giggles I'll sometimes drop a grape onto the edge. If it just bounces off, it isn't very sharp. If it is neatly cleaved in half, that knife is cutting. Not real scientific though.
 
richard j said:
would you say cutting cigarettes is the same?
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i think cigaretts are a little heavier paper, but take one apart and try it out! just break off the butt and slice it lengthwise and dump out the tobacco, then you should be able to hold it and try cutting the clean edge of the paper! otherwise rolling papers are cheap and you get a lot of them! :o
 
Nathan the Machinist said:
I don't actually shave bald, so I don't get the bald legs so bad. I float the blade 1/4" above the skin and knock the hairs off mid hair. If it doesn't grab any, it isn't done. If it pops a bunch of them, it is good. If it levels the field like a lawn mower, I did good.

Just for giggles I'll sometimes drop a grape onto the edge. If it just bounces off, it isn't very sharp. If it is neatly cleaved in half, that knife is cutting. Not real scientific though.
Click to expand...


wow! that is sharp!
how do you get them to that?
 
JoshTKnives said:
wow! that is sharp!
how do you get them to that?
Click to expand...

It is not really a big deal. I grind a new knife on a wet grinder to protect the temper. Then I have a bunch of big good old high quality oil stones and I just hand sharpen them. Rough, medium, fine, then a loaded strop. The entire process from start to finish takes less than half an hour. On a knife that has been sharpened before usually less than 10 minutes. It really is nothing special.

There used to be a weirdo around here named Cliff Stamp that would get them sharp enough to pierce the skin of a grape without pushing the grape. But he probably spent a lot of time on it. And an edge like that is gone on the first sheet of cardboard you cut.

The difference between a knife that will shave and a blade that will tree top hair is about one minute on a loaded strop. That may the secret you're looking for.
 
I try to shave off a piece of finger nail. If you can get it to peel off in a roll its sharp.
 
Cut cheap cigarette rolling papers lengthwise (Not J-B papers [golden pack, somewhat premium papers] as they are less of a challenge) without tearing them. It's harder than shaving hair, I find if I can cut the paper without tearing, it'll shave without irritation (hair popping sharp)
 
Nathan the Machinist said:
It is not really a big deal. I grind a new knife on a wet grinder to protect the temper. Then I have a bunch of big good old high quality oil stones and I just hand sharpen them. Rough, medium, fine, then a loaded strop. The entire process from start to finish takes less than half an hour. On a knife that has been sharpened before usually less than 10 minutes. It really is nothing special.

There used to be a weirdo around here named Cliff Stamp that would get them sharp enough to pierce the skin of a grape without pushing the grape. But he probably spent a lot of time on it. And an edge like that is gone on the first sheet of cardboard you cut.

The difference between a knife that will shave and a blade that will tree top hair is about one minute on a loaded strop. That may the secret you're looking for.
Click to expand...


Thanks! sounds like i may need to spend a little more time on the stones!
I have been using the buffing wheel rather than the strop for the final. any detrimental effects there?
thanks!
a little sub thread:o
 
see if you can slice a hair in half ! or filet a piece of paper. try cutting toilet paper slicing !
 
well if you nail the heat treat and know how to work a burr back and forth then clean it off adn finish the sharpening
one slice in news print will tell you if you have any ruff spots
so far as razors best test is to shave with them and make sure as they can be a real bear to get shave ready
 
butcher_block said:
well if you nail the heat treat and know how to work a burr back and forth then clean it off adn finish the sharpening
one slice in news print will tell you if you have any ruff spots
so far as razors best test is to shave with them and make sure as they can be a real bear to get shave ready
Click to expand...

I shaved two week growth with the very first knife I forged. I used a leather wheel to sharpen it.

The newspaper test is pretty good. definitely will tell you if you missed a spot. If it will push cut newspaper it is sharp enough for me.
 
I also find that the less noise it makes while cutting paper the sharper it is. I had a knife a while back that could cut newsprint almost un-heard, it was so freakin sharp.


-Josiah
 
Leu Custom said:
see if you can slice a hair in half ! or filet a piece of paper. try cutting toilet paper slicing !
Click to expand...

I tried that :thumbup:. Even knife shaves arm hair without any pressure a to fillet clean cut a thick toilet paper needs extra sharpness. This is my final test on sharpness before a knife is finished...
 
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