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The age-old question of how to sharpen a knife is critical to chefs, barbers, hunters and fishermen, survivalists, and DIYers. Sharpening metal edges requires an abrasive material that is harder than the metal itself – in the form of ceramic or tiny mono- or polycrystalline man-made diamonds glued together to create a sharpening stone.
Sharpening vs. Honing
There’s a difference between honing and sharpening metal knives, and some experts suggest honing a knife every time you use it. Honing doesn’t file down the metal – it just straightens and re-aligns the edge of the blade, removing any microscopic pieces of steel that may have chipped off during use. The sharpening process actually removes metal from the blade by grinding it down to form a beveled edge.
You can try an electric knife-sharpening machine, but generally, those tend to take more metal off your knife than is necessary. Hand sharpening requires a few specialized tools and takes some practice to achieve good results.
Sharpening stones or tools come in a range of grits, and you generally work from coarse to fine to get the sharpest edge.
There are two basic methods to sharpen a knife: hold the knife blade steady and swipe it with a sharpening tool, or fox a flat sharpening stone in place and move the blade across it at the desired angle.
Hold the stone (or the blade) at the correct angle (see below) and starting at the base, pull it towards you in a curving motion, pressing down firmly. Repeat the motion several times on both sides to create an even bevel.
You can eyeball the angle or you can buy one of several different styles of sharpening sets which provide a guide that takes out some of the guesswork, making a more consistent bevel angle along the entire length of the blade.
Choose your Angle
In general, the smaller the bevel angle on a blade, the sharper the edge. But the tradeoff is that a very sharp edge will dull more quickly. For filleting a bass or trout, you need a very sharp edge, so you might sharpen it to an angle of 15 degrees to 17 degrees. A survival knife used for many different types of cutting needs a durable edge, with a bevel of 25 degrees or more. Kitchen knives require precision and are usually sharpened to about 20 degrees.
The Leather Strop
One last step to the entire process is to use a leather strop, which helps remove any microscopic burrs left over from the sharpening process. You may want to use a diamond spray or stropping compound spread on the leather, which helps remove any leftover particles.
Tool steel bar, as the name suggests, is often used to produce tools, including knives. Tool steel is known for its extreme hardness, as well as its abrasion resistance and ability to hold a cutting edge at high temps.
Industrial Metal Supply offers tool steel bar in O-1 and A-2 grades, in square, round, and rectangular cross-sections.