How to Sharpen a Knife with a Rock

In a survival situation, your knife is your life. A dull knife is dangerous—it requires more force to cut, slips easily, and causes accidents. If you dropped your whetstone or forgot it, you are not out of luck. The world is full of abrasives.

Here is how to improvise a sharpening station in the field.

Method 1: The River Rock (The Nature Way)

You need a smooth, flat stone. Sandstone is excellent (medium grit), while Quartz is often too hard and glassy.

1. Find a Stone: Look in river beds. You want a stone that feels like rough sandpaper on one side and smooth paper on the other if possible.
2. Lubricate: Spit on the stone or use water. This floats the metal filings (swarf) away so the stone doesn't clog.
3. The Angle: Hold the knife at a 20-degree angle (imagine a matchbook under the spine).
4. The Stroke: Push the blade forward across the stone as if you are trying to slice a thin layer of skin off the top of the rock. Do this 10 times per side.
5. Check for Burr: Run your fingernail across the edge (carefully). If it catches, you have raised a burr. Now switch sides.

Method 2: The Car Window (The Urban Way)

This is the best kept secret in sharpening. The top edge of a car window is unfinished, rough tempered glass. It acts like a high-grit ceramic rod.

1. Roll the window down halfway.
2. Run the knife blade along the frosted top edge of the glass.
3. This is excellent for honing (straightening) a rolled edge, similar to a kitchen steel.

Method 3: The Coffee Mug

Turn a ceramic coffee mug upside down. The unglazed ring on the bottom is essentially a ceramic sharpening stone.

1. Place the mug on a table (use a wet towel to stop sliding).
2. Use the same 20-degree angle.
3. This produces a razor-sharp edge suitable for fine carving or skinning.

Stropping (The Finish)

After using a rock, the edge will be "toothy" and rough. You need to strop it to align the microscopic teeth.

• Leather Belt: Pull the belt tight. Drag the knife backwards (spine first) along the rough inside of the leather.
• Cardboard: The cardboard back of a notepad works surprisingly well as a strop.
• Jeans: In a pinch, strop the blade carefully on your denim thigh (spine first!).

Conclusion

Don't let a dull knife slow you down. Look around. If it's harder than steel and has texture, it can sharpen your blade.