The Zen Of A Well Sharpened Blade
I've gotten so many questions about sharpening knives that I decided to post this tutorial. If you've got a better way or think I've just got it wrong, please feel free to go to the Feed Back Forum and share you're knowledge with others.
How do you get a knife so sharp? It's probably the number one question any decent knife maker gets asked. If not, the maker probably needs to read this. If so and the maker is honest, they will say something like practice and patients. Those are the first things you need to hand sharpen a knife. If you just want to buy some sharpening system that makes a knife feel sharp and cut, edge geometry and job requirements are all you really need to know. But you won't get that "Oh, Damn" edge that leaves people with cut thumbs and astonished looks. A truly shape knife does not feel sharp. A blade that feels sharp is produced by the drag of a course edge. A truly sharp blade cuts before you feel it!
What's the Job
If you do much research on the subject you'll find a lot of pundits of blade tech promoting 16 degrees, 32 in the overall angle as the perfect angel for ultimate sharpness. This belief probably dates back to ancient Japanese sword smiths and knife makers. Personally I don't know what the perfect angle is, but I do know that the angle should be Job Specific! Any angel between 25 and 35 degrees in the overall will feel very sharp indeed. The question is, will it get the job done repeatedly?
The Zen of Blades
Shallow angles are really good for work preformed on soft materials. Jobs like cutting leather, capping (removing pelts from game), filleting fish or processing small game. A shallow angle combined with a hollow ground blade glides easily through the work. Since there is little chance of hitting hard materials such as heavy bone, there is little chance of chipping or rolling the edge. Rolled or wire edge is the most common cause for loss of performance for cutting tools. A chip can be lived with since it only affects a single spot on the blade. A rolled edge affects performance over a large section. If you have ever had a knife that felt really sharp but got dull after a couple of cuts, it probably had a wire edge. Barbers have used the tendency toward rolling in shallow angle edges for centuries to provide clean, pain free shaves with straight razors. The familiar leather strop is not meant to sharpen a razor...it simply controls the rolled edge of the blade so it contacts the face in a predictable manner. Cool huh? However, just like knives, if the edge becomes blunted or chipped the barber has to resort to the honing tools. As the edge is stood up toward steeper angles, angles that approach 45 degrees or so, they become more durable. It also requires more force or pressure to do the work. The advantage is if the job requires a durable edge and there is a risk of contact with heavy bone, the steeper angle edge will finish the job. Processing large game like deer or elk fits this job description.
Good Luck! And Contact Me if I can help!
Edge angles less than 45 degrees tend to blunt and roll. I prefer to sharpen the edge to a 35-45 degree angle, depending on the job. Choose an angle to provide the right combination of cutting ease and durability for the work. I mentioned practice and patients earlier. Experience adjusting these angles will get you the perfect edge for the job your tool needs to do. I have my own preferences for the knives I make, but if I told you I'd have to kill ya. No matter the angle, to get the best results...you must be patient! Use the finest/hardest OIL STONE you can buy. Yes they are expensive, but they are worth it. Diamond, ceramic, steel and other common rods and stones are fine for course sharpening or adjusting edge angle. Otherwise, they should only be used on extremely damaged or dull knives. These sharpeners work because they create a microscopic saw edge. Fine oil stones create microscopic saw edges too, but they are much finer. It is like the difference between a hand saw for wood and a hack saw for metal. Even if they are made from the same metal, the few large course teeth of a hand saw will cut faster and dull quickly in hard materials. The many finer teeth of a hack saw will continue to cut consistently even as it dulls. Whatever the geometry or system, the trick is to apply the same number of strokes per side, have a light touch, smooth stroke and be patient. I actually start my first stroke toward me pulling into the edge and count 1-10 alternating strokes toward and away from me, being sure to follow the edge contour. At he end I start over with the first stroke away from me. It almost becomes a kind of Zen like or meditative exercise. At least that's what I tell myself to relieve the tedium. To test that you have not produced a rolled or wire edge, simply lay the edge on your thumb nail just like you did on the sharpening stone and this time drag it away from the edge of the blade. If the edge is rolled it will scrape a little curl off of your finger nail. Simple huh? But please, be careful. If you've done it right you are holding a very sharp tool. Rolled edge is usually caused by applying to much pressure as you sharpen. Let the stone do its' job. There are sharpening systems that help you hold the blade at a fixed angle on oil stones. They work and can free you to concentrate on those pressure and profile parts of the process. But a sharp knife requires a lot of time and most of these systems slow down the process. This induces a loss of patients in me and a tendency to want a courser stone. Not good! So, I suggest practicing on cheap knives and learning the Zen of a well sharpened blade.