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How to Sharpen your Knife Without a Sharpening Stone

Avatar for James Walton James Walton  |  Updated: March 13, 2020
How to Sharpen your Knife Without a Sharpening Stone

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“Tony! Gimme that blue handled one,” I shouted to the knife sharpener. Every week Tony showed up and collected most of our knives in a small wooden box. He took them for a day or two and returned them as sharp as razor blades.

“I love this big blade, man. It’s a thing of beauty.”

At the time I was hoping to converse and compliment Tony. I was too young to understand how sick of knives Tony probably was.

The blades returned so sharp they would dig into and grab the deeper parts of our plastic cutting boards. They cut through thick-skinned grape tomatoes like nothing.

It was at 16 years old that I began to understand the importance of that sharp blade. I also learned that the type of steel you depended on was important, too. In a week’s time, these knives would need to be sharpened again.

They were cheap and probably made from 420 stainless knife steel which will not rust but it will wear pretty easily.

So, let’s take away Tony and your own tools. Do you know how to sharpen your knife without a sharpening stone? You might be surprised at the variety of unconventional sharpening methods available to all.

Less Than Ideal Sharpening Methods

It’s important to note that these are less than ideal sharpening methods. These methods present many challenges and safety risks. In other words, it’s easy to slip up and cut yourself when you are using sandpaper to sharpen a knife.

Ideally, these methods are something you play with at home under safe conditions and only turn to as a last resort in a survival situation.

The likelihood that you are going to achieve a perfectly sharpened knife edge on a coffee cup is pretty low. It will take focus and determination. I will give you a trick to make this easier but keep that in mind.

If you find yourself needing a sharp knife and have no other option, these methods could also be the difference between having a life-saving tool or a dangerous dull blade.

Use the Marker Trick

This is a neat little trick that you can use to teach people how to properly use a sharpening stone but also how to use one of these alternate methods.

Using a coffee mug or a car window to sharpen your knife offers a much smaller surface area to run your blade over. This will make it easier to miss areas during the sharpening process.

The goal when honing or sharpening a blade is to keep a consistent angle and hit all parts of the blade evenly. For this reason, I avoid knives with strange angular features and points.

Gimme a good drop point blade and I am a happy camper or prepper… or whatever else I am up to!

To do the marker trick you are going to use a blue, red or black magic marker to, carefully, draw a line of ink over the blade edge. This should run the length of the knife-edge on both sides of the knife.

Beginning to sharpen your knife will rub off the magic marker and it will be very clear where you have sharpened the blade and what you have missed.

The part of the edge that still has ink on it needs more attention.

Use this trick on some of these unconventional sharpening tools. It will help you be more accurate and result in sharper blades.

How to Sharpen your Knife on a Coffee Mug

You probably don’t give much thought to your coffee mug.

I used to wash dishes at a diner near my high school. It was fast-paced and chaotic. I would take 10 coffee cups at a time back to the waitstaff on one hand! We would slide 2 on each finger and they were about 180 degrees right out of the dishwasher.

These cups were durable and went through heated dishwashing many times per night. A coffee mug is kiln fired, glazed and fired again. That is how it gets its sturdy makeup.

However, during the firing process, the cup must sit on something. All coffee mugs have a ring around the bottom, where it sat to be fired, which is unglazed and abrasive.

This little abrasive ring is the perfect spot for some knife sharpening. You can utilize that ring to work your knife edge over and over just like you would a sharpening steel.

Larger mugs, like the popular tankard style or steins, are often smooth but unglazed across the bottom of the entire mug. This gives you an even larger surface to work your blade on.

Be sure to stabilize the cup before you start sliding your knife edge a crossed it.

How to Sharpen your Knife on a Car Window

You hear things from people sometimes and you just know they are full of it. I remember the first time I heard someone mention that you could sharpen a knife on a car window.

Visions of a geared up survivalist rubbing their knife vigorously over the windshield pane flooded my mind.

Why on earth would anyone waste their time using a flat smooth surface like a window to sharpen anything?

Until I saw the technique in practice I didn’t understand it.

Whether you realize it or not, your passenger and driver side windows have an abrasive edge at the top of each window. You cannot see it when they are rolled up and you barely notice it when you roll them down. That edge is strong and has a fine abrasion.

To turn an ordinary car window into a knife sharpener you are going to need to start by rolling that window down most of the way. You don’t want the abrasive top to disappear into the door but you want the window down as much as possible.

This will stabilize the glass and protect it from cracking or shattering under the pressure of driving the knife back and forth on it.

From here you can start working your blade edge, at a 30 degree or so angle. Take your time and use long strokes along the length of the blade. Alternate sides until you have achieved the desired edge.

How to Sharpen your Knife with Sandpaper

The Samurai were insane about the making and sharpening of swords. They applied the whetstone in a variety of grits and also demanded 100 strokes on each side of the blade before moving to the next stone.

Shiaji Togi is the process of using sandpaper to bring out the tempering line on the blade. This was a process that followed the whetstones but was still effective in creating a deadly sharp blade.

If you don’t have that sharpening stone you can use sandpaper, too, just like the Japanese would have.

Rather than stroking the blade onto another abrasive surface, you are going to be rubbing the sandpaper on your blade directly. This presents a few safety situations that you need to consider before starting.

Safety Tip #1 Put your knife in a vice to keep it stable. It only takes a little movement of that blade. You can quickly go from sharpening the blade to the blade slicing through your index finger.

Safety Tip #2 Wear some gloves in case you do make a mistake. This is not the safest way to sharpen a blade.

How to Sharpen your Knife with Rock

The earliest cutting tools were made from crushing rocks on a larger anvil rock. These would be set on the anvil rock and larger rocks dropped onto them. Our ancestors were looking to create fine fissures and sharp edges in the pieces of shattered rock.

About 11,500 years ago the Clovis people refined this ancient process using a technique called flint napping.

Once metal came along making knife blades from rocks was basically obliterated but we still use stones to sharpen our knives today. While these stones are rectangular-shaped consistent in grit, you can use the right rock to sharpen your knife in the wild.

Seek out a smooth river rock from a local water source. These rocks are the very best for sharpening because they are porous and because you can find surfaces that have been smoothed out by the water.

Finding the right rock is the important part. Look for something that is stable, consistent and smooth. From here you are going to simply treat this rock just like you would a whetstone.

Can you Sharpen a Knife with Another Knife?

This is one of those interesting questions that many people have little experience with. Sharpening a knife with another knife is an interesting proposition.

As I mentioned earlier, the sharpening of blades using these methods is not ideal. Keep that in mind.

Many of us carry more than one type of knife in our bugout bags or our EDC. That means we have a solution to sharpen our knives even when we cannot even find a proper rock!

The best method is to have a knife with a 90-degree spine. This should resonate with you because that 90-degree spine is a characteristic you should look for in any survival knife.

You will run the blade of the dull knife over the 90-degree spine of your other knife.

This is probably going to be more of a honing method than a sharpening method in all honesty.

The tricky part of this method is that you need to secure the knife you are using as a sharper so it will not move. How you do this could compromise the edge of that knife. That is not a great situation.

I am not a big fan of this method but it’s a method. Do with that what you will.

How to Hone an Edge with a Honing Steel

Most knife sets and kitchens have that strange black-handled tool with the long metal pole on the end of it Most people store that thing in the back of a drawer somewhere and forget it exists. If it’s in your knife blog there is a change it has never left it’s home!

This is called a sharpening steel but it’s really a honing tool.

When your blade goes from radically sharp to less than that, which is the case with most blades that we carry regularly, you can use the honing steel to bring that edge right back.

You don’t need to even consider using a stone, a car window or anything else.

How to Hone an Edge with a Leather Belt

I see the barber of yesteryear.

It’s a man with black hair that is slicked back with Brill cream. (Dad showed me how to use Brill cream for my elementary school dances.) This barber has a clipped mustache that is twisted and waxed at the ends. He wears a black vest over a white buttoned-down shirt and a white apron.

He carries a straight razor and a leather belt. He whips that straight razor up and down the belt a few times before drawing it perilously close to his customer’s skin.

That leather belt is a powerful honing tool. Much like the honing steel, this piece of leather is used to align your blade. This is a tool that is incapable of sharpening a dull blade. Keep that in mind.

You could also use a leather strop for this. The strop is a tough piece of leather that is backed by wood, typically.

You will be amazed at the capability of simple honing. The polishing and aligning of a blade can take a knife that feels a little dull and turn it into something that is razor-sharp.

Whether using the belt or the strop you will want to use long and even strokes on both sides of the edge. Use our marking trick to be sure you have affected all parts of the blade.


A sharp blade held tremendous value in my previous profession as a chef and that didn’t change when I started into the prepping and survival world. Having the right tools and skills to sharpen a knife is paramount.

In survival, you could find yourself without all your tools or even with nothing but a survival knife. All of these methods will work to make a dull knife work better. As long as you take your time and practice safety.

I guess we also love some good survival tricks, too, right? Who doesn’t wanna break out the coffee cup around the campfire in the start sharpening your knife to the OOOHS and AAAHs that would follow?

So, rather driven by the showmanship of it, the ego or the true need to sharpen a knife by any means necessary, these methods will work. They are hardly ideal under normal circumstances but they can certainly hone, align and polish a knife-edge.

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