A knife is one of the most important tools a hunter takes into the woods. But a knife is only as good as its edge. A dull knife will make any job difficult and frustrating and can actually be more dangerous. One of the most useful skills any hunter can develop is the ability to properly sharpen a hunting knife.
The key to sharpening a knife is in maintaining a constant angle between the knife and the abrasive sharpening medium. Some craftsmen can do this by hand on a bench stone, but for most the best way to start is to use a kit that includes a clamp that will hold the knife blade to maintain a constant angle. Among the best known are Lansky, Gatco and DMT. Consider a sharpening kit to be your "training wheels." It'll teach you the correct angle and technique for sharpening a knife.
1.) Clamp the knife securely in the fixture and do not remove it until the sharpening job is complete. Select the angle best suited for the way the knife will be used. The higher the angle number the longer the edge will last, while the lower the number, the sharper the knife will be. For most hunting knives, about 20 to 25 degrees is a good choice.
2.) The next step is to recut the blade's angle. This is building the foundation for the sharpening job and must be done correctly for a good outcome.
3.) Select the coarsest stone available and use plenty of pressure on the knife blade while moving the stone in and out perpendicular to the blade's edge.
4.) Cover the full length of the knife along the sharpener. Overlap your work as you move along the blade by about a third of the stone's width.
5.) Continue until you can feel a defined burr on the other side of the knife edge. This burr must be along the entire length of the blade. Use the sensitive tip of your finger to feel the burr, but never run your finger along the burr as that will result in blood leaking out and you saying bad words in front of your kids.
6.) Once you have a defined burr along the entire blade, flip the knife over and work the other side until you raise a burr.
7.) After both edge angles are properly cut, switch to a medium grit stone. Start with the opposite side you finished on and use moderate pressure as you stroke the stone. Work one side, then switch to the other, using the same pressure. End with light pressure on the stone as you polish the edge.
8.) Now switch to a fine grit stone and repeat for at least three passes on each side. Decrease the pressure with each pass, so that the knife edge becomes fine.
9.) It is possible to create a sharp edge with a "fine" grit stone, but for the best edge switch to an ultra-fine stone and continue.
10.) I believe that a knife is truly sharp when it will cause the hair on my arm to "pop" off as the edge contacts it, but the lawyer-approved method is to slice the edge of a sheet of paper.
How to Sharpen an Ax
A hunter should also know how to sharpen an ax. This is usually done freehand rather than with a fixture. It's best to clamp the ax in a vise, but you can get by with laying the ax on a table with the cutting edge hanging over. A very dull ax or one with a lot of dings and chips in the edge may require that you use a file to first repair the edge.
Always try to maintain the original angle. Watch how the color changes in the steel as you file. That indicates where you are removing metal and if the angle is correct.
Work both sides of the blade equally and be cautious that one side does not have a different angle than the other.
The width of the angled edge on the blade is an indicator of the sharpening angle. Make sure that the width of the angle is the same for both sides and that it is constant for the length of the edge.
Then switch to a bench stone and use plenty of oil. Use the coarse side of the stone first and work the stone back and forth, 90 degrees to the edge. Move along the edge, overlapping by one third of the stone until you have worked the entire length of the ax blade.
After several passes with decreasing pressure with the course grit, switch to the fine grit side of the stone and continue to work both sides of the blade edge with decreasing pressure until the ax is sharp.
Not all Steel is the Same
The type of steel determines how many strokes and passes are needed. Carbon steel sharpens easily while some types of stainless steel are much tougher and may require several passes. The hardness of steel is measured with the Rockwell scale and the higher the number, the harder the steel. The harder the steel, the longer it will take to sharpen the knife, but harder steel also keeps its edge longer.