How to sharpen a knife with a file? Learn the technique and how to do it

Junior Dorigatti 02 de January de 2024

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A well-sharpened knife ensures cutting precision, instrument functionality, and extends the utensil's lifespan.

As it is used, it's normal for the cutting ability to be lost. Therefore, there are different sharpening materials to restore the cutting edge. A file is one of the most frequently used tools, after all, it's easily found at home.

In today's post, we're going to show you a super simple step-by-step to make your knife's edge super sharp using a file.

Check it out.

Step-by-step on how to sharpen a knife with a file

Knife and file in hand, it's time to start!

Step 1: The file has a smooth surface and a textured one. Rest the knife on the smooth surface of the tool.
Step 2: Starting from the handle and going to the tip, run the file along the entire blade of the knife. This movement needs to be done on both sides of the utensil.
Step 3: Finally, check if the cut is adequate. If it's not yet good, repeat the process of running the blade on the knife until you reach the desired sharpness.

If you also have a dull knife but don't have a file, we recommend reading the post "How to sharpen your knife? Practical tips and suggestions!" to learn other sharpening techniques.

What is a file?

A file is a sharpening tool composed of a steel rod with grooves. Available in manual or mechanical formats, it can be used on items such as knives, pliers, saws, hoes, and even wood.

What are the types of files?

Due to its wide range of uses, files can be found in 7 types:

File type	Recommended use
Flat file	Ideal for flat and curved surfaces.
Round file	Recommended for concave surfaces, holes, and rounded openings.
Rectangular file	For angled bases and right-angle corners.
Square file	Used in flat areas, corners, and even for adjusting holes.
Half-round file	Can be used on both flat and curved surfaces.
Knife file	Recommended for corners.
Barrette file	For finishing details.

Which is the best file for sharpening knives?

The recommended ones are those with a single cut, meaning those with parallel diagonal lines going in only one direction. To choose the best file for sharpening a knife, it's necessary to pay attention to the tool's tooth type.

Besides the single cut, there are two other types of cuts:

Double cut: has two groups of teeth, one in the opposite direction of the other. This type of file has more force, so they are used to remove excess material;
Coarse cut: is formed by a set of individual teeth. Because it has an aggressive cut, it can be used on wood, aluminum, and even lead.

You might also be interested in: Kitchen knives: 6 types of versatile knives!

How do I know if my knife needs sharpening?

There are several ways to tell if your knife needs sharpening:

Check if the knife is gliding over the food surface or if it's "pulling" or "scraping" when cutting. If you feel you need to apply a lot of force to cut or if the knife is sliding sideways, this may indicate that the blade is dull.
Look at the edge of the knife and see if it looks dull or worn. If the edge is rounded or appears worn, it's likely that the knife needs sharpening.
Try cutting a piece of paper. If the knife doesn't cut easily and in a straight line, it's likely that it needs sharpening.
Check for small burrs on the edge of the knife, which may indicate that it needs sharpening.

Remember that a well-sharpened knife is safer and more efficient for cutting. If you notice that your knife needs sharpening, you can look for professional sharpening services or go back to the beginning of this post and check out our complete step-by-step guide.

What movement should you not make with the file?

Automatically, the usual thing is to make back-and-forth movements, but these are precisely the ones that are not allowed.

The teeth of a file are positioned upwards, and when this action is performed, the sharpened utensil ends up going roughly backward, completely losing its cutting function.

By making the wrong movement, you not only jeopardize the quality of your knife but also the functionality of the file.

Where to buy a file for sharpening?

Files can be found in construction material stores, tool shops, and even marketplaces. The product price usually varies, and simple alternatives can cost up to R$ 20.00. Kits or personalized versions can cost over R$ 200.00.

There are also stores that sell sharpeners specifically for knives. Here at CIMO, in addition to sharpeners, we have knives for various niches, barbecue products, cutting boards, and other kitchen-related items.