Edge of Glory Knife Sharpener - Consumer Reports Magazine

How sharp is this device?

Consumer Reports magazine: May 2013

The claim. Edge of Glory, two tungsten carbide teeth set in a plastic base, is claimed to be "The World's Best Knife Sharpener!" A video boasts of its skills, including the ability to sharpen a credit card, which is then used to slice a tomato. We paid $11 plus $7 shipping and handling.

The check. We took pairs of chef, santoku, and serrated knives that were equally sharp, dulled one of each pair, used Edge of Glory to sharpen the dulled knife, then compared its cutting skill with that of its twin. We cut ham, dried sausage, tomatoes, carrots, onions, and celery. And we sharpened a credit card and did battle with a tomato.

Bottom line. Try Edge of Glory if you need to slice a tomato with a credit card. That trick worked. Otherwise, the device is not so sharp. It's worth using only if:

The knife is not too dull. (The four quick swipes shown in an ad work only if the knife is already fairly sharp.)
The knife is not of hard metal. (That makes it tougher for the device to work.)
The serrations aren't small. (They can catch on Edge of Glory's teeth.)
You don't need a knife edge that's super-smooth. (The sharpener left a fairly rough edge.)
You don't care that the knife is sharpened from one side only. (One of the device's teeth sharpens while the other holds the blade; knives can get an asymmetric or "chiseled" edge.)