Sharpness Testing Machine

I do a few things to determine sharpness. First, I scrape the edge 90 degrees across my finger pads (I've done this enough that I can tell where an edge is at), and after testing that across the blade, I then run the edge along my fingernail to see if there are any places that are not consistent with the rest of the blade. Once that's done as a quick and dirty check, I'll start making dinner, or cutting food. It seems the best way to figure out how good your edge is, is to test it at what it's supposed to do.

 

Call me crazy, but to test sharpness I use the knife...to do knife stuff. That celery test is akin to the Wonderlic or the 0-60. IE a pretty useless predictor of success. Who stores cut veg for 3 or 9 days?

 

Just what I meant earlier. Haha

It might tell you some about the thickness behind the edge, but only if you can obtain perfect sharpness every time and in some magical way the knife you sharpen is not getting thicker after the session - cause you want some kind of repetition to check things out, isnt it?

Gordon Ramsays Kitchen Nightmare ?

 

I like food tests most but I don't always have food around to test on, so when I sharpen I start with newspaper folded loosely and not creased, so it has a radius about the same as a fat pen, and then try to cut it. Rounded edges which might slice an unfolded sheet of paper and shave easily will slide over the larger surface area without biting in. Sometimes instead of newspaper, I use plastic such as heavier garbage or parcel bag, again with a large-ish radius fold.

Then the real test is food, but the paper and plastic tests have predicted the performance well and are in convenient reach. Shaving hair is pretty easy but only gives me a very basic idea of whether or not my bevel is set. Three finger test I've never figured out since I can't seem to read much from it on anything, including Carter's edges.

A testing device is cool, but too involved for me because I'm lazy.

 

"Who stores cut veg for 3 or 9 days?"

I don't think that was the point. As I read it, the point was that sharpness can affect various aspects of the quality of the food that is cut, e.g., its ability to retain indications of freshness and flavor if subsequently stored. But there may be other subtle examples of the differences, such as the intensity of flavor that will be released during cooking (though to me it is not immediately apparent whether food that is more cleanly severed with a sharper knife would release more flavors than a more roughly cut version -- sort of the difference between crushing garlic and cutting it).

 

How does it cut food, that is all that matters.

 

I actually use packing bubbles to test the sharpness of the knives I make, they need to be able to cut thin slices cleanly without tearing them.

 

I use them at work. It's a pretty reliable test.

 

This is basically what I do. The paper is ultra thin catalog print (newsprint is a similar density/thickness). Much like Robert I suppose, just a wider diameter rounded surface. As you can see the angle of 'attack' is pretty acute, and the primary edge angle is going to determine the minimal angle of cut (the missed cut was too acute an angle, not a lack of sharpness). That said, if the edge isn't sharp enough, it won't pierce the 'skin'. This tests toothiness for me, as well as the overall polish. This is also a good way for me to check for any remaining burr, as it is easily able to be felt in the cut. In addition, a burr will cause the blade to 'deflect' rather than cut in if it's turned to one side or the other.

 

and sing... Space Lord Mother...

 

Hey, whatever works!

 

I certainly don't need some crazy contraption thought up by Cliff Stamp to see if my knives are sharp.