The Science Behind Knife Sharpening

Whether chopping veggies or skinning fish, most knives require a sharp edge to do their job. But what makes a good knife edge?

Many people use so-called sharpening steel commonly found in kitchen drawers. But it doesn’t sharpen the knife – instead, it hones the existing blade edge by sweeping it across the steel at a certain angle.

Understanding Angles

Most knife owners know they should sharpen their knives regularly. But only some understand the difference between sharpening and honing.

The edge of your favorite kitchen or utility knife may look like a smooth ridge of metal, but if you looked at it under a microscope, you would see that it’s made up of microscopic notches. These notches allow the blade to cut through food, making it less durable.

To determine the correct angle kitchen knife sharpening Savannah GA, you must first figure out what angle it was originally sharpened at. You can do this by asking the manufacturer or a knowledgeable knife shop. It is generally accepted that an angle between 10 and 30 degrees per side will be appropriate for most kitchen and camp knives. Shallower angles create a sharper but less durable edge, while steeper angles will split rather than slice through veggies.

Understanding Blade Geometry

A blade’s geometry includes the angle of its cutting edge and several other factors that contribute to how it cuts. It also determines how hard or soft the metal is and its toughness (the ability to resist impact damage).

The choice of angle depends on the type of knife and steel. A knife with a more acute edge will be sharper but less durable. For example, a fillet knife doesn’t need a durable edge, so a slightly lower angle might be better.

Once the angle is set, it’s time to start honing. Honing steel realigns the edge and helps maintain its sharpness. But if the blade is dull, it must be re-sharpened with an actual sharpener that removes material to create a new edge. Using a marker to color the edge can help you see when you’ve reached the correct angle. When the marker starts wearing off, you know you have honed the blade to its proper angle.

Understanding Sharpness

In general, a sharp blade is skinny at its edge. This makes it lighter and more maneuverable. However, it is also more fragile and less durable than a thicker blade.

The correct or best angle balances these characteristics and is determined by the knife’s design, type of use, and steel. In this way, we can create an edge that is sharp and durable.

When we hone a blade, we draw it repeatedly across a fine-gritted stone with light pressure. After 2-3 strokes on each side, inspect the slope and sharpie markings to ensure you maintain the correct angle. You should only remove a skinny layer of metal from the angle when honing, so it is essential to keep the pressure light. If the marker is wearing away, you are likely going too shallow with your angle and not reaching the apex of the edge.

Understanding Sharpening

It may seem obvious, but the key to getting a knife sharper (even with a manual system that doesn’t highlight the angle of the edge) is to drag the blade – heel to tip – across steel at the correct angle. This will align the microscopic boundary of the blade.

While a blade’s cutting edge looks like a smooth ridge of metal, if we looked at it under a microscope, we’d see that it’s made up of tiny jagged teeth. That “hair edge” helps sever meat but wouldn’t hold up to digging in hard soil.

We must remove some material from the edge to make a knife sharp. To do this, we need to use a tool known as sharpening steel. Sharpening steel has a rod with a rounded end that you drag the blade along to create a new, slightly more comprehensive, but still very narrow edge. This will help a sword cut through denser materials without damaging the blade.