I like knives and probably have too many and I like to keep a good working edge on them. Now I believe that a sharp knife is safer than a dull one. It requires less pressure to use and you can use better cutting techniques. So I have a whole pile of sharpening stones, see the link for information on stones Sharpening Stones, How to Clean Sharpening Stones. But what happens when you don’t have good stones, can you make improvised knife sharpeners?
Now the secret to sharpening any knife, regardless of the type of steel used in its manufacturer and intended purpose, is to maintain proper angle alignment while sharpening. If a proper angle is not kept, you risk dulling the edge of the knife. The degree of angle will vary depending on the knife’s intended use. This can vary from between 10 to 30 degrees. For cutting and slicing purposes, a 22-degree angle should be maintained, while razor sharp knives should have a lower sharpening angle and skinning knives should have a higher angle. The lower the cutting angle the thinner the cutting edge of the blade. This will make it more susceptible to chipping under hard use.
When sharpening, I make a sweeping pass across the surface of the sharpener, as though I am attempting to slice a thin layer off the top of the sharpener.
When I don’t have a good stone available, the first thing I will check for improvised knife sharpeners is the kitchen. Find a ceramic plate or cup. Turn them over and there is normally a ridge on the bottom that the cup or plate sits on. This makes a good sharpening surface. Check, several ceramic or glass dishes and you will find that some are smoother than others are. Use a combination of these and you can get a good edge on a knife.
Another easily available item is the top edge of the side window glass in your car. Take a look at it and you will see that it is slightly rough. Both of these techniques work well.
There are many other techniques that I have heard of but not tried. They include sandpaper, limestone, ceramic tile, bricks and even using toothpaste or ash on hard cardboard. I think that all of these techniques would have some validity, and in an emergency I would try them.
If you have successfully used any of the above improvised knife sharpeners, let us know whether or not they were successful for you.