If you can’t seem to find the perfect angle, you can always cheat. Hunt down the knife’s specs and you’ll know how many degrees away from the edge to aim for. A bowie knife for instance, usually has an angle of about 14 degrees away from the sharpened edge on both sides of the blade. If you know your specs, you can measure your angle with a protractor (if you don’t have one, you can always print out a protractor here: Protracter). Then again, it’s OK if you change the blade’s angle — so long as the change isn’t all that drastic. A blade with a wider angle away from its edge is better suited for chopping. A blade with a tighter angle will be sharper. The key here is to start small using gentle strokes. If you find that you’ve altered the blade’s angle, don’t worry, you can always get it back to the shape you desire.
Archive for the 'Basic Sharpening' Category
Unless you are more experienced, scratching is going to happen when you sharpen your blade. By studying the marks you leave, you can get an idea of how uniform your sharpening strokes are or aren’t. The closer you can keep them to the blade’s original shape and angle’s, the better off you are. If you’re leaving scratches near the back of the blade, you’re holding the blade way too flat against the stone. Over time you’ll get the feel for how to hold and stroke the blade against the stone and you won’t scratch your blade during sharpening. One way to get around this problem is to use an DMT aligner sharpening system. This will guide the blade and keep the angle from changing while you sharpen. DMT has a system like this for under $50. Well worth the money. I have personally tested these angle systems. They are a little slower to use but work well to set the desired angle and produce a razor sharp edge without so much as a single scratch to the blade. Another tip is to roll the knife on the edge to feel where the flat of the edge is. Then you sharpen on that flat edge angle.
Straight knife blades are the most straightforward of all blades, making them the perfect place for beginners to start. Begin by carefully studying the blade in a well-lit space. Hold the knife so the edge points up. Peer down the length of the blade making note of all nicks and flat spots, which will be apparent in the light. The duller the blade, the coarser the stone you’re going to have to start with. Typically, there are three “stages” of sharpening, with Stage 1 referring to the most intensive part of the process. It requires a coarse stone with a grit level of 200 or less. Stages 2 and 3 refer to sharper blades that only need touched up. 2 and three are the final stages of attaining a razor sharp edge.
Practice on a knife blade you’re not particularly fond of before moving onto your prized possession. It may sound silly, but you’ll be happy if you notice that you’ve scratched your crappy blade and not your best one while you were learning the ends and outs of sharpening. Beginners have a tendency to press too hard or use too severe of an angle when learning to sharpen a knife. They also tend to use less water or oil than an experienced knife sharpener. Throughout the entire process, you should be able to see a small pool of sharpening lubricant on the stone. If the honing oil or water changes color or gets streaky, that means there’s debris trapped in it. Stop sharpening and rinse the stone off. Then, reapply your lubricant and get back to work.
Backpacker Magazine published a free video on knife sharpening with some information to absorb. It’s called “Keep Your Knife Sharp” from the Backpacker’s Gear School.
You should treat your sharpener almost as carefully as you treat your blade. If the surface gets damaged that means it’s uneven, which can damage or groove your blade. Always wrap your stone in cloth before storing. If you used oil, make sure there’s still a layer of it coating the stone before you pack it away. If you used a water- or petroleum-based oil, wash your stone with soap and water before stowing it. If you see streaks or filings on your blade, be sure to clean the surface until it’s smooth and spotless. Never use an abrasive brush on your stone. If you must clean it heavily, a soft-bristled toothbrush, or even your finger is enough.
As your arm tires while sharpening your blade, it’s tempting to switch to a powered grinding wheel. Most people should avoid that urge. Warranties do not extend to knives that have been sharpened on wheels and damaged. The chance of scratching or chipping your blade goes up. So does friction, and that means your blade will heat up rapidly. Eventually, this could burn the temper from your blade and, in the process, greatly weaken it. That said, if you’re sharpening blades en masse you might have little choice. One of the best ways to approach sharpening blades in this manner is to remove the cover from your bench grinder and flip it around 180 degrees. This way, the wheel will travel upwards, rather than downwards, giving you more control and decreasing the likelihood of a chip in your blade. Be sure to get a wheel with a very slow revolution rate, or outfit it with an “electronic speed controller” available at most hardware stores.
What you’re looking for is water or “honing oil,” which is manufactured by several knife and knife accessory companies. There are two types of honing oil: water-based and petroleum-based. With diamond stones, use water or water-based honing oil. Petroleum-based oils work great with natural sharpening stones. If you’re out in the woods, you might spit on the stone before beginning. Keep in mind, though, once you’ve decided to use oil, stones don’t take to water very easily, so you’re going to have to stick with oil for the life of the stone.
Ask two different knife enthusiasts about using honing oil and they’ll tell you two different things. Some believe oil inhibits sharpening by never really letting the blade touch the stone — in effect, just polishing it rather than sharpening it. We’re of the other camp that suggests oil or water is a good thing. It lessens the friction you’re exerting on the blade, and that means it’s more forgiving if your hand slips. It’s also smoother and it keeps natural sharpeners clean by whisking away your excess filings.
Diamond sharpening stones are sharpening stones coated in micro-diamonds. What’s inside the “stone” isn’t necessarily a chunk of rock. It could be metal or a composite stone manufactured mechanically. Diamond is one of the hardest substances on Earth. By coating a stone in diamond powder, it ensures you’ll be able to sharpen even the strongest blade, and the porous surface provides an escape route for filings that come off your blade. This keeps gunk from building up on the stone and hampering its effectiveness. DMT sharpening stones are some of the most popular of diamond sharpening stones.
