Broken Secrets

Why Some Knives Have Serrated Blades

August 6, 2010 at 5:00 am Chad Upton 7 comments

By Chad Upton | Editor

Good knives are expensive, but they’re money well spent when you consider they may outlive you.

There aren’t many purchases you can say that about and like anything that lasts, they need care and attention.

In fact, Japanese samurai swords endured hundreds of years of use, when properly cared for by a Togi professional — a sword polisher whose apprenticeship lasts ten years.

You’re probably aware that knives need sharpening, but do you know why they get dull in the first place?

It’s not just from repeated use, but from repeated misuse. Some misuse is expected, especially with serrated knives.

When you cut on a surface that is harder than the knife blade, that surface dulls the blade by creating a microscopic flat surface on the bottom of the blade. The flat surface is too small to see, but it makes a big difference in the cutting ability of the blade. In knife manufacturing, electron microscopes are used in quality control to inspect the sharpness of the blade.

To keep your knives sharp, it is best to cut on cutting boards made from soft materials such as various types of wood or plastic. While it’s convenient to cut directly on solid surface counter-tops such as granite and quartz, it’s not good for your knives and neither are glass cutting boards.

Plates are a common surface to cut on, but they’re bad for knives. Serrated blades help solve this dilemma; the points touch the plate but the raised edges above the points do not. Therefore, the points are dulled, but the other edges stay sharp.

Serrated blades also work well for cutting through hard rinds of some produce, and crunchy bread crusts too. The sharp points add more localized pressure, allowing better cutting penetration on the foods and act like a saw when the knife is moved back and forth.

There are other practices that can dull your knives too. Letting the cutting edge bang into other utensils in a drawer or the dishwasher can cause nicks and scratches, which adversely affect the knives’ sharpness.

To keep your knives in good repair, you should use a honing steel on the blade for about 30 seconds before each use. It helps remove scratches and bends in the blade, but it does not sharpen it.

For sharpening, a good manual or automatic sharpener should be used every few months. Professional sharpening should be done every few years. Many serrated blades cannot be sharpened, but a honing steel can be used on some.

Broken Secrets

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Sources: Cutco, Electric Knife Sharpeners Blog, Sword Forum Mag, Wikipedia (Serrated Blade)

Entry filed under: Around The House, Food and Drink. Tags: blade, dull, knife, knives, serrated, sharp, sword.