Whether it’s a tool or cutting instrument, obtaining the perfect edge seems an unobtainable myth to many users and outdoorsman. I hear it said, more often than not, grab some oil and a stone and you’ll have a perfect edge…. but in fact, before you can even begin to master the “know how” of sharpening you have to first have a little knowledge about the shape and angle of an edge.
Much of what I’ve learned has come from personal experience making knives as well as conversations with fellow knifemakers and gleaning insights from studies published by commercial cutting facility research. Some of this information surprised me and may surprise you as well. Through application of what I’ve learned, I have found that sharp can usually become sharper if you know what you are doing and I hope the following information will get you started with a few basic approaches.
The first thing to consider before sharpening is whether you are trying to create a “chopping” edge or a fine cutting edge. Your answer will sometimes mean a single vs. a double-edged face. While an axe often has a single edged face from its thick backside to its cutting edge, a knife usually has a double-edged face. The angle sought for most axes is 55 degrees while knives might range from a 20 to 44 degree total edge (or 10 to 22 degrees per side) depending on the thickness of the blade itself or just how sharp you want to make the blade. Once you determine the desired angle, you’re close to getting started.
While there are many approaches that might work, you’ll want to approach your sharpening technique after determining how bad your current edge might be. When and edge is really dull, I’ve found the best method is to use a course stone, fine stone, and leather strop. With the angle in mind, the most important thing to determine is if you can reach your secondary edge without bottoming out on your primary edge when sharpening. Think of this as two angles on one side of your blade where the grind of your blade moves toward the edge (see picture). Many times, a blade will be thick and have a low/shallow grind leading to your edge. If this is the case, the most important thing to do is grind down your primary edge on a course stone. When this is done, you’ve created clearance to sharpen your secondary (cutting) edge. Using the coarse stone on your edge, maintain your desired angle of approximately 22 degrees. Pick your angle and stick with it – this is key!! Use guides if needed but make sure you maintain your angle throughout each stroke. Switching sides every few strokes, feel for a “rolled” over edge or “burr” that’s been created by moving the blade backward (the opposite as you would to shave something) across your finger or fingernail. The burr will be created on the opposite side of the edge you last sharpened. Once you can feel a fine wire that’s been left on the edge, you’re ready to move to the fine stone.
Alternate just a couple strokes per side on your fine stone – again, maintaining your angle! Feel your edge to see if the “rolled” edge has come back to “true” – once it has, the fine wire-like burr has been removed from your edge. Usually, this will get you to shaving sharp and you can finish off the process by running your blade backwards a few times on a leather strop to fine tune your edge and you can even add a little polish to make your edge shine.
In the event you’re just honing your blade and it’s not very dull to begin with, some folks choose to begin making even strokes on a ceramic or fine diamond grit sharpening rod. This can work very well and again, you’re maintaining your angle and taking your time on each stroke – not like you see on tv, quickly running a large knife across the rod and expecting a fine edge.
Notice oil was never mentioned! Studies under high-powered microscopes have shown that oil does not help to create an edge and to the contrary, can actually ruin a good edge by allowing metal shavings to remain in the oil and rub against your edge (this is counter-productive). Not all adhere to this theory but it’s hard to debate what’s seen under a microscope. Keep your stones clean and you are well on your way to a sharper edge.
While this is just an introduction to sharpening, I’d be remiss not to mention a little about safety. Always remember to keep your cutting tools sharp. A sharp tool is easier to use, cuts cleaner through your intended object avoiding forceful and jerky movements
prevents many accidents. As when handling a firearm, I’ve taught my son not to aim the edge or point of a knife at something he doesn’t plan to cut (like himself!). Safe sharpening and enjoy your blades.
Comentários