The Mechanicsof KnifeSharpening

The apex of a knife blade is the very tip or point where the two sides of the bevel meet. The apex radius refers to the radius of the curve at that point. A smaller apex radius means a sharper, more acute point, while a larger apex radius means a more rounded, less sharp point.

Imagine a very sharp needle. The point is extremely fine and tapers to a tiny, almost invisible point—that’s like a knife with a small apex radius. It's incredibly sharp and can easily penetrate materials, but it's also more delicate and prone to damage.

Now imagine a dull pencil. The point is more rounded and less defined, like a knife with a large apex radius. It's not as sharp and may require more force to cut through materials, but it's also more durable and less likely to chip or roll over.

Understanding knife sharpening angles is crucial when learning how to sharpen a knife. The aim here is to create a new bevel on the blade that meets the sharpening surface at a specific angle.

Here’s a quick tip: To visualize the angle, imagine a line extending from the blade’s spine down to its edge. The angle between that line and the sharpening surface is your sharpening angle. One of the best knife-sharpening tools for beginners is a blade-mounted angle guide.

As you sharpen a knife, a burr will form on the opposite side of the edge you're working on. This burr is a thin wire of metal that indicates you've successfully sharpened that side of the blade.