How to Sharpen a Combat Knife? – 3 Simple Methods

Written by

John Cotton


Logan Miller

how to sharpen a combat knife

There are both dedicated and home alternative methods to sharpen a knife in order to keep it in tip-top shape.

Especially if you keep a survival knife close for the purpose of self-defense, and in various emergency situations, you must make sure to stock up on knowledge on blade maintenance. After all, you have to sharpen a switchblade for it to serve its purpose in the first place!

With all the tools and methods involved, this task can be quite overwhelming. So, to help you with this, here is a simplified guide on how to sharpen a combat knife.

Method 1: Have It Done by Professionals


Incorrect sharpening may damage your blade. So, having a professional do the work is always a good idea.

One of the most notable services in America is Knife Aid, with its headquarters located in Los Angeles county. Aside from walk-in customers, they service customers beyond Los Angeles too, as long as shipping services cover the area.

Method 2: Sharpening With Sharpening Tools

If you wish to sharpen your knives by yourself, your best course of action would be to choose the appropriate tools to go about it. Especially when you’re looking to sharpen specialized knives such as a military knife or a double edged combat knife, it is vital that you get both the tools and the techniques right.

The following specialized sharpening tools are your most common options:

1. With Whetstone


Whetstones are like knife sharpening stones that are rectangular and have a surface texture similar to sandpaper. If you get the techniques right, whetstone sharpening will yield the best results among other combat knife sharpeners and tactical knife sharpeners.

What to prepare:

  • Whetstone – You can choose from multiple grit levels, but the 200, 500, and 1000 grit whetstones are the best variants when looking to sharpen a dagger.
  • Water – Any type of water works since it simply serves as a lubricant for the whetstone
  • Your knife


  • Step 1: Set up your workstation by choosing a flat and sturdy surface. This is vital since a wobbly work surface may tilt the whetstone and affect the resulting edge of the blade.
  • Step 2: Lay your whetstone on the table. Secure the whetstone between the holder, tightening it as needed.
  • Step 3: Take note of the bevel of the knife edge’s angle. This is usually indicated in the product manual.
  • Step 4: Wet the whetstone and place it in a lengthwise position while you angle your combat knife horizontally. Your dominant hand should be gripping the knife handle while the other hand should keep the blade flat.
  • Step 5: Run the blade along the whetstone in a base-to-tip fashion. Your hands must be putting pressure on the blade just enough for its edge to make contact with the surface of the whetstone.
  • Step 6: After four or five glides, wet the whetstone once more and proceed to the other side.

2. With pull through knife sharpener


If you are worried about getting the angles right when using the whetstone, you may opt to use a pull through knife sharpener. This knife sharpening system comes with two abrasive surfaces that are fixed and pre-set into an ideal angle.

Other advanced models come with an angle adjustment wheel which offers more flexibility and control.

What to prepare

  • The pull through knife sharpener – Some models have more than one slot to cater to various blade types and angles, sometimes even including a slot for scissor blades.

Make sure to choose a sharpener that has a comfortable, non-slip handle.

  • Your knife


  • Step 1: Choose a sturdy surface such as a countertop in order to ensure your safety when sharpening. Place your sharpener atop your work area.
  • Step 2: Insert your knife between the two abrasive panels of the pull through sharpener and starting from the edge of the knife closest to the handle, thrust the blade backward until the tip reaches the panels. Then do the reverse by thrusting the blade forward.
  • Repeat this four to five times as well on each side of the blade
  • Step 4: Rinse and then wipe dry. Test the blade’s sharpness by cutting through a tomato or something with similar texture.

If this results in an easy and clean slice, that means your knife is sharp enough.

Method 3: Sharpening With Household Items (Home Alternatives)

If you’re in urgent need of a dagger sharpener, you may consider doing it at home without tools. The following home alternative methods are your best bets:

1. With Sandpaper


The sandpaper’s abrasive surface makes for a good blade sharpener. It’s even good enough to sharpen a machete with sandpaper!

Similar to the whetstone, you can choose from a variety of grit levels, but the 220 to 320 grit sheets of sandpaper may be the best when it comes to sharpening a very dull knife.

What to prepare:

  • Sandpaper with chosen grit level
  • A stable surface
  • Your knife


  • Step 1: Hold the sandpaper flat against a table or countertop with your less dominant hand, while you firmly grasp the handle of your knife with your dominant hand.
  • Step 2: Start by slicing one side of the blade onto the sandpaper at a 20-degree angle. Do this three to four times and proceed to the other side of the blade.

2. With A Brick

When sandpaper isn’t available to you, the next best thing to do is to look around for objects with abrasive surfaces. A brick is ideal, although its surface may be more inconsistent compared to that of the sandpaper.

What to prepare:

  • A brick
  • A rough or concrete surface
  • Water
  • A working space


  • Step 1: If the brick has a very rough and inconsistent surface, begin by rubbing it against concrete or rough pavement.
  • Step 2: Wet the brick with water
  • Step 3: Revisit the gliding motion involved in sharpening using a whetstone; do the same, repeating equally on both sides of the blade.
  • Step 4: Rinse your knife and wipe it dry.
  • Step 5: Test its sharpness using the method indicated earlie.

Frequently Asked Questions

What angle do you sharpen a tactical knife?

Most tactical knives include a product description or a user’s manual wherein its ideal sharpening angle is indicated.

If this is not indicated, or there is no way for you to check, the general rule of thumb is following a 20-25 degree angle.

How do you sharpen a rough knife?

Rough or serrated knives use a special ceramic honing rod for sharpening. Run the rod through each gullet of the knife’s bevel. Finish up by getting rid of metal burrs using a fine grit whetstone or sandpaper.

What types of knives can not be sharpened?

All types of knives can be sharpened, not just in the same way. For example, as answered in the previous FAQ, serrated knives are sharpened using a different tool and require a different technique compared to most traditional knives.


This guide has covered all you need to know about how to sharpen a combat knife.

Before considering buying a new set of knives, or getting yourself that new self-defense double sided knife model, make sure sharpening them is a task you can handle well.

As with any equipment, maintenance is key for long and quality use. Feel free to get back to this guide anytime you may have a sharpening task at hand.

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