HOW TO SHARPEN A KNIFE
Quick! You’re going on a wilderness trip. What tool do you value most? If you said “a good sharp knife”, you’re in agreement with the experts. Most people use a mechanical device of some sort to sharpen their knives. This is fine as long as “moderately sharp” is good enough and you have space to carry the sharpening tool. Actually, it’s easy to sharpen a knife to a razor’s edge. All you need are the right tools and practice.
This method works with any non-serrated blade.
A medium-grit and fine-grit whetstone. You need a coarse grit stone only if the knife is badly nicked or very dull. The quality of the abrasive is more important than whether the stone is natural or synthetic. Indeed, Amazon natives use water-worn rocks to sharpen their machetes—and they obtain whisker-sharp edges. Use water to lubricate diamond stones and cutting oil, lamp oil (kerosene) or WD-40 on natural stones. For safety, your stones should be at least six inches long.
Important! If you want the finest edge—and the ability to sharpen your knife in the field—don’t ever use an electric sharpener on the blade! Why? Because the angle cut by machine is difficult to duplicate by hand. And never use an abrasive power wheel on a good blade. You’ll run it beyond repair!
1. Begin with the coarse stone. Raise the back of the blade about 15 degrees and cut into the stone. If you set the back of the blade of on the edge of a penny, the sharpening angle will be about right (this method only works with narrow blades, like those on traditional jack knives and Swiss Army knives). Hold this angle while sharpening and you’re good to go. The key to a sharp edge is to precisely hold the same angle when you sharpen. Exotic-looking tools that clamp to the knife blade are sold for the purpose of maintaining the proper sharpening angle. These tools work great for people who don’t know how to sharpen knives by hand!
To sharpen Scandinavian-style blades: Do not use a 15 degree angle. Instead, hold the beveled portion of the edge flat against the stone.
2. Hone one edge until a burr appears on the opposite side—you can feel it with a finger. Then hone the other side until a burr appears. Switch to the fine stone and continue sharpening, alternating sides every few strokes until the burrs are gone. Maintain a film of light oil (natural stones) or water (diamond stones) to float away steel particles that may otherwise clog the pores of the stone. Clean the stone (wipe off the surface and apply clean oil/water) frequently to keep suspended grit from dulling the sharpened edge.
3. If you want a polished razor edge, finish honing on a superfine Arkansas stone, then strop the sharpened blade on a piece of leather. Strop the edge away from the leather—one stroke per side.
To check for blade sharpness: A knife is considered sharp if it will shave hair from the back of your hand. A less barbaric method is to shine a bright light on the edge. You should see no flat spots, no inconsistencies . . . nothing!
TO SHARPEN SERRATED BLADES
You'll need a "conical diamond sharpener" to restore dull serrated edges. Several companies make conical stones; the one pictured above is by DMT (Diamond Machining Technology). A serrated blade will last for many years if you occasionally true the edge with a conical sharpener. But if you don't have one, you can simply swipe the blade a few times across your flat stone--two or three strokes per side are usually enough. Overdue it and you'll destroy the tiny serrations. A sharpening steel will work too.
1. Grit clogs the pores of sharpening stones and they become “finer” (smoother) over time. You’ll prolong their life if you occasionally “boil them out.” Simply submerge the stones in boiling water (with a few drops of detergent added) for a few minutes.
2. Sharpening (butcher’s) steels do not sharpen a knife; they merely realign the microscopic teeth of the edge. A steel is handy for touching up a knife (it’s simply a coarse version of a leather strop), but it can’t take the place of a genuine whetstone.
3. If you dip the blade of your knife in boiling water for about thirty seconds, it will be easier to sharpen.