How to Sharpen a Knife

There are many different kinds of knives and blades on the market. Some help you chop vegetables quickly, some are for producing thinly sliced meats, and others are for self-defense, everyday tasks, shaving, and even ceremonial purposes. You likely have at least one kitchen or pocket knife in your home.

An important part of owning and using any knife is its maintenance, which includes keeping it sharp. This is your guide to sharpening different kinds of blades, how to use various sharpening tools and the difference between sharpening and honing.

So how do you sharpen a knife? It really depends on the type of knife being sharpened, but generally, you will use a knife sharpener, sharpening stone, or sharpening rod or steel. With each of these methods, you should pull the knife, rather than push on it.

How to Sharpen a Knife

There are several methods you can use to sharpen a knife. The one you choose will largely depend on the type of knife you want to sharpen – a pocket knife will require a different method of sharpening from a large sword, for example.

For the most part, it’s best to pull the knife towards you while sharpening it, regardless of which method you choose. This is safer and more effective than pushing the knife with force.

Remember to practice safety when sharpening any knife. Even the bluntest knife can cut you when you try to sharpen it if you’re not careful.

sharpen knife with stone

The main methods of sharpening knives include:

  • Knife sharpener
  • Whetstone/sharpening stone: Best method for pocket knives.
  • Sharpening steel/rod
  • Honing steel

How to Sharpen a Pocket Knife

Pocket knives can be challenging to sharpen, due to their small size. Caution should be exercised for this reason. The best method for sharpening a pocket knife is with a sharpening stone. Follow these steps to safely and effectively sharpen your pocket knife:

  1. Apply a lubricant. You can purchase special sharpening oil or use water, but mineral oil is the best lubricant to use. Pour plenty of oil on the blade, enough to coat the entire surface.
  2. Place the blade flat on the rough side of the stone, called the rough grit. Raise the blade to an angle of 10-15 degrees.
  3. Start pulling the blade towards you across the stone. Make sure you are sharpening the entire edge. For curved or long blades, this may mean sweeping it across the length of the stone. Only apply moderate pressure. Repeat your strokes several times.
  4. Repeat the process for the spine of the blade.
  5. Alternate your strokes. After you’ve sharpened the edge and the spine, start flipping back and forth between them for a few strokes.
  6. Turn the stone over to the finer side. You will repeat the entire process on this side of the stone – first the edge, then the spine, then alternating strokes.

How to Sharpen a Serrated Knife

Serrated knives, such as bread knives and certain pocket knives, also pose unique challenges, due to their serrated edges. A sharpening rod is the best way to sharpen serrated knives. The following steps will keep your serrated knives sharp and effective:

  1. Insert a small sharpening rod into one of the gullets of the knife. The gullets are the curved grooves between the teeth of the serrated edge.
  2. Run the rod through the groove away from the knife. Use slow, smooth motions and only apply light pressure. Only go in one direction, rather than back and forth.
  3. Move on to the next gullet until they have all been polished.
  4. There’s no need to sharpen the teeth – by polishing the gullets, you are sharpening the teeth at the same time.

How to Sharpen a Ceramic Knife

Ceramic knives are often used in the kitchen because they supposedly never grow dull, though this claim is usually a marketing gimmick. Ceramic knives do, in fact, become dull and dangerous. This will typically take six months or so, but it will happen eventually.

The challenge with sharpening ceramic knives is the fact that they are very brittle. But it can be accomplished, with extra care and a sharpening stone.

Follow these steps for success when sharpening a ceramic knife:

  1. Apply mineral oil or another lubricant on the entire surface of the blade.
  2. Place the blade flat on the rough side of the stone.
  3. Due to the brittle nature of ceramic knives, a two-handed approach is needed when sharpening. Place one hand on the handle and the other on the spine of the blade. Use the latter to guide the blade along the stone, making sure to sharpen the entire edge. Use light pressure to keep the blade from snapping.
  4. After doing this several times, turn the stone over to the fine side and repeat the process. Remember to keep a firm grip on the knife.

How to Sharpen a Sword

The best way to sharpen a sword is to use a whetstone. However, swords are larger and heftier than your typical kitchen or pocket knife, so the technique is a bit different. These steps will help you sharpen a sword:

  1. Lay out the sword on a table and prop up the point with a block of wood.
  2. Using a 30-degree angle, shape the edge of the sword with a metal file. Run the file down the entire length of the blade in slow, even strokes.
  3. Carefully turn the sword over and repeat the process on the other side.
  4. Apply mineral oil to the surface of the blade.
  5. Run the blade across the whetstone at a 30-degree angle. Make sure to use both hands for extra safety.
  6. Repeat on the other side of the sword.
  7. Run a small piece of 400-grit sandpaper along each side of the edge. This will give the sword a more uniform look, blending the newly sharpened edge into the rest of the sword.

How to Sharpen a Straight Razor

Straight razors provide a close, clean shave and can last a lifetime. They do need periodic sharpening, though – typically, every few months. If you notice more of a tug on your hair or razor burn, it’s time to sharpen your straight razor.

Sharpening is best done with a whetstone. These steps will help your straight razor stay sharp:

  1. Make sure both sides of the blade are clean.
  2. Apply mineral oil or another lubricant to the whetstone.
  3. Place the blade flat on the stone.
  4. Guide the blade along the stone.
  5. Flip the straight razor over and do the same thing with the spine of the blade. Make sure to use the same amount of pressure that the edge received.
  6. Continue to alternate between the edge and the spine until you feel it is sharp enough.

How to Use a Knife Sharpener

Knife sharpeners can save you time when sharpening your knives. There are two main types: electric and pull-through.

An electric knife sharpener features rough sharpening surfaces that rotate inside the machine. Some may also have multiple stages with both rough and fine grits. This type of sharpener is very easy to use – you simply pull the knife through the sharpener, applying little to no force.

automatic knife sharpener with motor

A pull-through sharpener is very similar to an electric one. The main difference is that it is manual rather than electric. It is also often smaller, which is why it is sometimes called a handheld sharpener. It features a stationary grinding surface. To use this type of sharpener, pull your knife through the slot across the grinding surface with moderate pressure.

How to Sharpen a Knife 1

How to Sharpen a Knife with a Stone

Sharpening stones are best for pocket knives, ceramic knives, swords, and straight razors. There are many kinds of sharpening stones available, from standard whetstones and Japanese water stones to pricey diamond-encrusted stones and everything in between.

All sharpening stones have two sides to them: a rough side and a finer side. These are referred to as “grits”. Generally, you want to start sharpening on the rough grit and finish on the finer grit.

sharpen knife with whetstone

The basic steps for using sharpening stones include:

  1. Applying lubricant on the entire surface of the blade or sharpening stone.
  2. Placing the blade flat on the rough side of the stone.
  3. Pulling the blade towards you across the stone several times, making sure to sharpen the entire edge. If you are sharpening a ceramic knife, use two hands to guide the blade across the stone. This will keep it from cracking, snapping, or shattering. Swords should also be sharpened using two hands.
  4. Doing the same thing for the spine of the blade if you are sharpening a double-edged knife, such as a pocket knife, or a straight razor.
  5. Alternating between the edge and the spine.
  6. Repeating the entire above process on the finer side of the stone.

How to Sharpen a Knife with a Rod

Sharpening rods are best for serrated knives. They come in a variety of sizes, and the size you choose will depend on your needs. For serrated knives, smaller rods are best. Keep in mind, though, that most sharpening rods are tapered, so even a larger rod may still serve your purposes.

knive sharpening rod

The method used will also depend on your purpose. For sharpening serrated knives, you simply run the sharpening rod through each gullet, going in one direction and applying light pressure. Repeat until all gullets have been polished.

How to Sharpen a Knife without a Sharpener

Sometimes you don’t have a sharpener, stone, or rod handy. In these situations, you will need to find some other method of sharpening your knives. The following alternatives can help you do just that:

  • Ceramic coffee mug: Turn the mug upside down and run the knife blade along the rough part on the bottom of the mug.
  • Sandpaper: Different knives will require different grits. Start with a coarser grit and work your way up until you find the perfect match for your knife. Run the edge of the blade along a small piece of sandpaper.
  • Nail file or emery board: These items are used in the same way as sandpaper, by running the edge along the nail file or emery board.
  • Car window: Glass is hard enough to sharpen knives, and the rounded edge of a car window is especially effective for sharpening softer knives. Slide the blade along the top of an open car window eight to ten times on both sides.

Sharpening Steel vs. Honing Steel

You may have heard of honing steels, which may have been mentioned alongside sharpening steels. What is the difference between honing and sharpening steels?

The main difference is that they are used for different stages of knife maintenance. Sharpening steels are used to sharpen knives that have become dull, while honing steels are used to keep a knife sharp that has not yet grown dull. Honing steels do not remove metal in the way that sharpening steels do; they simply maintain the knife.

Keeping Your Knives Sharp Improves Safety

Sharpening knives can sometimes be time-consuming, but not doing it will cost you in the long run. Dull knives are more dangerous than sharpened ones, resulting in time wasted on covering the cut or even going to the emergency room for serious wounds. Old knives that have not been sharpened in a while can become damaged or even shatter, resulting in costly repairs or replacements.

You can avoid all this trouble by taking the time to sharpen your knives. Sharpeners, stones, rods, and steels are all effective tools for keeping your knives sharp. Make sure to learn how to use your chosen tool and how to sharpen your specific knife. This will eliminate a lot of drama later on.

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