How do you test sharpness in your blades?

[yepimonfire]

The ease at which it cuts paper. A sharp knife will cut paper, a very sharp knife will make S cuts and an extremely sharp knives can cut half circle shapes. I quit using shaving as a measure, because paper does a better job of showing inconsistencies with the apex/burrs. IME messed up edges can still shave.

 

[jasonbournemp]

If I'm going for a refined edge I check to see if it will split a hair. For a sharp, but not ocd sharp edge I use a phone book. For a toothy edge I use a piece of micro fiber cloth to gently wipe the dust off the blade, if it cuts straight through without any resistance I stop.

 

[HeavyHanded]

I use the three finger sticky test, followed by some newsprint or industrial catalog paper. S cuts, circles, slow cuts that need to keep catching on the curl - if it will cut a circle I'm in the right place. As a finale will sometimes check for tree-topping leg hair. For a finale whittling a hair from my head but don't normally go that fine.

 

[CutterMcGee]

I used to use arm hair. But then I shaved it all off. Then the leg hair. I was thinking mowing south of the Border to test sharpness but my gynecologist advised against it.

 

[crowmagnon]

I just make sure my edges can slice magazine paper cleanly and shave my arm.

 

[Bob6794]

I use the three finger sticky test, followed by some newsprint or industrial catalog paper. S cuts, circles, slow cuts that need to keep catching on the curl - if it will cut a circle I'm in the right place. As a finale will sometimes check for tree-topping leg hair. For a finale whittling a hair from my head but don't normally go that fine.

I do this to some extent but I usually don't do the s cuts, circles, and last I checked I was vaguely hitting tree topping status for how sharp I could get a knife and I only did that for fun so I doubt I can whittle a hair.

 

[me2]

I thought you were talking about me for a minute. I only did that out of curiosity, but it was pretty entertaining. Normally I just use my arm or the back of my head for catching hair above the skin. I shaved my face a time or two with my Salt 1, just to see. It was entertaining to leave on the shower caddy hanging by the opening hole.


Video:
https://www.youtube.com/watch?v=2P4ZCawMN8c

I've seen that on YouTube several times. They take a paper thin slice off a tomato resting on a cutting board. In one in particular, he did the same thing with a grape. Now imagine something so small that moving it takes hardly any pressure. Yet he sliced a paper thin cut off of it, more than once. He even dropped a tomato, and subsequently a grape onto the knife blade from six inches up, both cleaved cleanly.

I adore some great kitchen knives, but I've never had any NEAR that kind of sharp.

EDIT: And here is said video ...

https://www.youtube.com/watch?v=7sQGKAVWbIg

 

[wazu013]

I just run my finger crossed the bade. Once in a while I'll flick the edge with my fingernail looking for a ribbon. That's usually if the knife was spoon dull to begin with. I'm not looking for anything crazy sharp. Just a geometry that is functional and long lasting.

 

[mexican]

Sometimes I look at the edge with a pocket microscope to look for micro burs, or small dings.

 

[Djrichone]

All the previous methods mentioned and in addition slice through paper towels, then slice through wet paper towels. Slicing through a wet sponge without squashing. Also, slicing through toilet paper or toilet paper wrapper.

 

[rogerxd45]

i used to use the arm/leg hair shave test but like others have said this isnt a very good test plus if im sharpening lots of knives i start to run out of arm hair. knives with less then ideal edges will still shave

now i slice thin paper with it. im not sure how to describe what it is im looking for but i can tell based on the feel and sound of the cut if the edge needs more work or if its as perfect as i can get it with my tools i have on hand

in culinary school i had two ways i would test the first was i would cut the top layer of skin on the pads of my finger from tip towards the first nuckle. with practice you didnt even have to look, you would be able to tell if it was sharp enough based on feel alone the second was test to see if it would catch the ridges of my finger print, when it was sharp enough i could feel it catching on them. the finger print test is also less likely to draw blood on accident

 

[me2]

Oh and one I forgot I sometimes use. I try to fillet the letters off a piece of magazine paper or even newspaper.

 

[DudeoftheDesert]

I have used most of the methods already mentioned, but here's another one that's useful to compare sharpness before and after honing or stropping; applies only to folding lockback knives: take a sheet of newsprint or phone book or whatever paper comes to hand. Open the blade to about 3/4 mast (blade is situated where it is almost fully open but hasn't locked in place yet). Slice into the paper as in normal paper cutting testing. You will probably have to fold the paper or use several thicknesses to get an adequate test in which the blade slices cleanly but not so much force is needed that will pivot the blade into the fully locked open position. Test again after sharpening, see if you can add more folds or sheets of paper still keeping the blade in same position (not rotating further on the pivot). This would not be very useful in knife to knife comparison, because each would have different pivot pin adjustment, lock mechanism friction, lubricant, etc.

This my first post. I have been "grazing through the fence" so to speak, for a couple of years, and most every knife related curiosity has been satisfied by doing a search on this forum. I just registered here a couple of weeks ago. You guys are certainly a knowledgable and generous bunch on anything knife related, so it's good to be here. Thanks. Desert Dude

The Dude abides.

 

[CryoGuy5272]

I use the shave test on my legs. I always wear jeans o my phone is the only person to laugh at the bald spots