testing for sharpness

I watched a show on the tube where they were sharpening knives and then using the fleshy parts of their thumbs and fingers to test for sharpness. My Dad could somehow make anything sharp enough to shave with, and taught me to drag the end of my fingernail lightly along the edge, a slight resistance meaning scary sharp.

Reply to
woodcraftssuch
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Sounds a bit dangerous if you don't know what you are doing there. I prefer just to try the common method of slicing off strips of paper with the blade.

-- Regards,

Dean Bielanowski Editor, Online Tool Reviews

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Reply to
Woodcrafter

I prefer the thumnail test -- YMMV

--RC

Projects expand to fill the clamps available -- plus 20 percent

Reply to
rcook5

I always seem to have patchy arm hair....bad habit I picked up from a knife and sword-making buddy of mine.

Reply to
mark

Rather than dragging anything that belongs to you along the blade, turn the blade crosswise to your thumbnail and, with the blade at about a ten degree angle from square to your thumbnail, just drop the blade down onto the nail gently, moving it slightly toward you. If it's truly sharp it will catch on the nail; it it's anything less than sharp it will skid.

Tom Dacon

Reply to
Tom Dacon

Knifemaker's Mange. Confused the hell out of my acupuncturist. She thought it was an iron deficiency, but I explained that was one mineral I certainly wasn't short of.

Reply to
Andy Dingley

That's on the FLAT of the nail, not on the edge, by the way.

Tom Dacon

Reply to
Tom Dacon

In which direction? I like to go in the plane of the paper, myself. :)

Mark

Reply to
Mr. Moose

I think he meant a crosscut.. I don't think a blade is sharp until it will resaw paper..

Reply to
mac davis

The sharper the steel the more effort it takes to cut meat. this seems weird but you need bigger teeth on the edge to grab meat and such. I had learned this when I got my first handmade Japanese kitchen knife. I sharpened it to 8000 and it was sharp. it fell through a spud but you had to saw meat with it. took it down to 1000 grit and man it cut meat like crazy. running a finger over the edge of a woodworking tool works well. You look for a slippery or oily feeling edge. the sharper it is the oiler it feels. I like this method because you can find any bad spots or missed burr's I have never cut myself doing this. it takes some force to do so. but don't do it on a kitchen knife (G)

Reply to
Steve Knight

works the same with a plastic ball point pen. the steeper you can get the knife to catch the sharper it is.

Reply to
Steve Knight

Asked my barber this same question. He's over 70 and I assumed he would know something about keeping a blade pretty sharp. He showed me by putting the blade at an angle on the top of the thumbnail. Adjusting the angle until it just stopped sliding. Also showed me his arkansas stone, and that when barbers purchased a blade, it came fully sharpeded and that all the barber had to do was use the leather to keep it that way.

Reply to
bw

If you're going to cut wood, why not test across the endgrain of a nice pine scrap? Shine = sharp.

Oh yes, cutting resistance is also a good indicator when using this process.

Reply to
George

To test carving tools for sharpness, nothing beats trying them on a piece of wood. Across the grain you can see where more work is needed. The best way to sharpen a knife to cut rope is on concrete. This makes a really terrible edge (for woodworking) but leaves plenty of teeth for severing the rope fibers.

Reply to
Dave W

What!? ... and then have to go through all that sharpening crap all over again?

Reply to
Swingman

Reply to
Steve Knight

Yeah, it's surprising how many people prefer to slice off strips of their fingers instead.

Reply to
Lawrence Wasserman

I think Leonard Lee explained this phenomenon in his sharpening book, but I can't remember the explanation.

You're absolutely right though. A knife that's sharp enough to shave DNA out of a hair cell won't cut meat worth a damn. Meat knives need some tooth. Tomato knives too.

Reply to
Silvan

because courser teeth have less surface touching so they grab better.

Reply to
Steve Knight

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