knife sharpening

Why have I become curious about knives and knife sharpening recently? Well, knives are practical, and so is knife sharpening. And knife sharpening seems to require experience, knowledge and skills of observation. Anyway, here's what I've learned about it after a morning reading about it.

First, there are tools: a sharpening stone and lubricant. Most stones come with two sides: a rough grit and a fine grit. The finer the grit, the finer or sharper you can get your blade. You usually start off sharpening on the rough grit and then finish sharpening it on the finer grit. Additionally, you would have to observe the grind of the blade. My kitchen knives and my pocket knife are of the sabre grind. Then there is the angle. No matter the grind, it seems that a knife's edge is nothing more than two planes that intersect along a line with a constant angle of intersection. As far as I can tell, this angle is between 10 and 20 degrees, but I'm not sure how you tell what it is for a particular blade.

Now for a brief description of the sharpening process. There are many methods, but the method/process of sharpening matters way less than the end result. A "dull" blade has some degree of ’rounded edge.’ A sharp edge is nothing more than two planes intersecting at a point. When sharpening all you are doing is removing metal until the bevels on both sides of the blade meet at a point. This can take six strokes or six hundred depending on the blade's current condition and the type and grit of stone you are using.

So, how can you tell if a good edge has been created? Look directly at the edge with a light behind you, and you'll notice that rounded areas will reflect light. Keep sharpening until no light gets reflected. The sense of touch can also be of use. Carefully feel the edge with a finger. Don't underestimate what you can learn this way. Does the edge feel rounded? Is there a burr? Are the bevels even on both sides of the blade? Finally, what's a good test of a well sharpened blade? Apparently, a blade can be sharpened so that it can sever a hair with almost no pressure applied.

See this link:

http://artofmanliness.com/2009/03/05/how-to-sharpen-a-pocket-knife/