What Is Sharp?
Sharpness is achieved by having the cutting edge with the molecules of blade material forming a smooth, even ridge.  The process of edge honing restores a cutting blade to a fairly fine edge, polishing the edge refines it even further, and makes the sharp edge last longer. Here is a simple explanation of why this works... if you were to microscopically enlarge the edge of a knife, the metal will be like a mountain ridge. Think of it this way, if the edge has not been polished (typically "ground" by most), the ridge line will be rough, as if covered by trees. As you use the knife, the trees will be knocked over, and will end up laying in random positions. If the edge has been polished, the edge will be smoother, like a ridge line devoid of trees (bare rock), and will not be subject to rapid dulling due to the random deformation of the trees. Of course, this is an over simplification, but you get the idea.

A sharpening steel does not sharpen a knife... it only pushes the "trees" back and forth, trying to realign them into a uniform ridge. Over time, using a sharpening steel will deform the metal, changing the angles of the edge, meaning what once may have started as, lets  say, 25 degrees, will end up being 30, 35, or 40 degrees or more. The typical comment we hear is that a person's steel "no longer seems to sharpen the knife"... that is because the metal has been deformed into a bad angle. Using a steel is not necessarily bad, just remember that each time you do use it, you are getting one step closer to needed to get your edge angles repaired.

From a practical standpoint, the edge angles should be correct for the intended tool use, the blade composition and the temper of the blade.  A kitchen knife lives a fairly sheltered life and can have a very slight angle, like 15-20 degrees. A hunting, survival, tactical or pocket knife lives a rough life, and should have an angle of between 25-35 degrees. The less the angle, the sharper the knife blade initially, but the cutting edge will be somewhat fragile. The opposite applies, the greater the angle on the knife blade the less sharp it will be initially, but the edge will be far more durable. Flat ground edges are more durable than hollow ground edges (done on a wet grinding wheel). An axe should have a smooth convex edge to help split wood.  The angle on a pair of scissors or shears depends on the material to be cut, the metal of the scissor blades, and in some cases each scissor blade has a different angle.  All edge angles should meet the exact needs of the intended use, and take the metal composition into consideration. Again, a fine cutting plain knife edge should be polished.

To test a knife for sharpness, we recommend doing the tomato test... can your knife easily slice a ripe tomato? Also, if you look at the actual cutting edge (look straight at the edge), you should not see any shiny marks or dings at the actual cutting edge... if so, your knife needs a little sharpening attention to restore the fine edge.  A sharpening steel cannot restore the proper edge angle on a knife.

To test a pair of scissors or shears, use the intended material as the testing medium.  If the tools slides, snags, or stutters along the cut, it needs to be reground.  We recommend the paper towel test, if the tool cannot cut a single piece of paper towel with little effort along the entire length of the cutting edge, it needs sharpening or repair. 

Consider this... good tools are an investment, and should be respected and professionally maintained.  You should be proud of your knives and scissors, and should expect a long, useful service life from all of them.
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