How to Sharpen a Knife like Angus MacGyver

These days, folks have learned that packing a minimal amount of equipment means you can go light and fast through the wilderness.  Most people through-hiking long distances may even consider a pocketknife, the traditionally essential tool of the outdoorsman, to be superfluous. Personally I won’t go anywhere (well, except a plane cabin these days) without a pocketknife or multitool.  However, except for when I’m doing sharpening demonstrations or if I’m out planning on using my knife extensively for say, fishing or bushcraft, I never bring a sharpener. I usually don’t need to sharpen on an outing, but I do have a few tricks up my sleeve, just in case. I’ve occasionally been stuck with a dull knife in situations where I didn’t have a specially designed sharpener handy. A dull knife is not a knife; it’s a metal bar, unless you know how to sharpen it with everyday materials.

Sharpening a knife isn’t an arcane and mystical process, but there is certainly a technique to it. This article isn’t going to cover the comprehensive aspect of grinds, bevel angles, or the basic techniques, but it will cover some handy materials that can be used instead of strops or sharpening stones for free-hand sharpening. My fancy Japanese kitchen knives get treated to a set of waterstones and strops loaded with polishing pastes and diamond sprays, but the fact of the matter is that any material that can make a knife dull, can be used to sharpen a knife. To put it another way, dulling a knife is just sharpening it in the wrong direction. So let’s talk about some of the materials you can use in a pinch to sharpen your knife.

The old coffee-mug trick:
If you have a ceramic coffee mug with you, either at home or at camp, chances are it’s glazed inside and out. However, when the mug was fired in the kiln, the very bottom of the mug wasn’t glazed so it would release from the kiln without damage. If you flip over your mug, the rough surface in a circle around the bottom edge works very much like a modern ceramic sharpening stone. It may be too fine or too rough of a grit for perfect performance, but it will do the trick. Just sweep your blade across the rough area at whatever angle you prefer (12-22 degrees is the norm) on both sides of the edge until you feel the edge getting sharp again.

The edge of a piece of glass:
Heaven forbid you break a nice beer bottle in the wilderness! No, we’re talking about the edge to your car window. Very much like the coffee mug, the edge of your car window will be rough, and will act like a ceramic sharpening rod. Just roll down your window and expose a portable sharpening stone.  Beach glass is also great for this, but be careful, as most beach glass is very small. If you do use beach glass, try wedging it in a log first so you don’t cut yourself.

River stones:
The original sharpening stones were, well, stones. While it’s unlikely you’re going to be able to dig up some perfect examples of Belgian Blue, Novaculite, or carborundum, two fairly flat river stones will likely get you through. Start off by wetting the stones, and rubbing their flattest side together for several minutes. Then use the flatter stone and the stone slurry that was created like you would a wetstone or oil stone.

Cardboard and newspaper:
This is one of my favorite tricks to use around the house and while working. If you ever have to break down a lot of boxes, you know that cardboard can dull a knife very quickly. The reason for this is because cardboard is a pretty dirty compound with lots of grit and sandy particles suspended between the paper fibers. You can use this to your advantage, by stropping your knife on some folded-up cardboard between cutting up boxes. I once sharpened up a friend’s custom knife to a mirror-finished edge with nothing but cardboard and rolled up newspaper, just to see if I could, and honestly it works amazingly well. Murray Carter estimated that cardboard is probably somewhere around 30K grit, and works excellently as a finishing strop when paired with regular stones!

Hone a knife with … a knife?

Another overlooked option is to use the back of a second knife, or a buddy’s knife, the same way you would use a sharpening steel at home. Stick with the flattest part of the spine of their knife, and try to avoid any nicks or scratches on the surface. Your mileage may vary depending on the type of steel in both knives, but there’s no reason it shouldn’t work for most knives.

Belts and nylon webbing:
This is a cool little trick to whip out in the woods. You simply take a leather or nylon belt, or perhaps a long strap from your backpack, and smear one surface with a thin layer of mud. Stand on one end of the strap and pull it tight with your non-dominant hand. With your dominant hand, strop your knife on the muddy side of the strap until you feel the knife getting sharp (be careful when determining this with your fingertips). Then strop for about half as long on the clean side of the strap, and you should be good to go!

By Hans Schneider