Interestingly enough, not every knife collector knows how to sharpen a knife. It that spins against the blade of your knife sharpening the cutting edge and giving you the pleasure of swift-slicing. Spine – the back of a blade, opposite of the edge. I can always tell a poser who doesn't know how to use a knife he has one of these. Re: how to sharpen a curved knife blade beercan: thanks for the link. How to Use a Sharpening Rod . Some of these fancy knives sell for over $100. When your knives see frequent use, though, they’ll begin to dull over time. Unusual design. Eventually, the blade won’t cut like it used to, and you’ll need to sharpen it back to its former glory. Big long fancy handles and hardened steel that is hard to sharpen. All 19 of the crooked knife blades that I've worked on have bevels on the conventional/upper side. I can only imagine that the bevel is on the underside/outside of the blade to do that much work on it. This is true even for the average kitchen knife. Here are the methods by which you can sharpen your mower blades… This produces a thin and wickedly sharp edge but it’s not durable and needs constant maintenance. Think of how a cave curves in, or think "con-cavity". In addition, it has about 4 to 5 slots to provide a different range of coarseness so that the amount of sharpness can be varied according to requirement. When sharpening your lawnmower blade, the idea is to make the blade as sharp as a butter knife, and not razor-blade sharp. Not sure where to start? Get a wide blade (not the narrow blade) and they come left and right handed. The sharpener has the ability to narrow a 20-degree western distorted knife to a sharper 15- degree edge. Concave – shapes that curve inward, like an hourglass. Methods of Sharpening the Blade. A sharpening rod (like this one) is rather like a honing steel, except it's smaller and narrower, and it tapers to a point, which means it offers various thicknesses along the shaft of the rod.This is helpful because the serrations on different knives are different widths and you want to apply the section of rod that best fits the serrations of your knife. This is to ensure its effectiveness since the blade rotates at a high speed. Primary Bevel / Grind – Where the knife first begins to narrow into a cutting edge from the thickness of the main stock of the blade. The hollow ground blade has a characteristic concave grind to the edge, so that both sides of the knife have a bevel that is bowing inward until they meet. Convex – shapes that curve outward, like a football.