I found a quick and easy method for sharpening high-speed steel router bits when I was doing some 1/4-in. radius roundovers. I didn’t have the appropriate stone or file to sharpen the bit, so I took some 400-grit wet-dry sandpaper and wrapped it around a 1/2-in. dowel. By pulling the paper taut and holding it between my thumb and forefinger, as shown in the drawing, I was able to use the paper like a file to quickly sharpen the bit. Now I keep an assortment of short lengths of dowel and 400- to 600-grit paper on hand to touch up all my concave bits. You can also use sandpaper wrapped around a wood block as a sharpening-stone substitute for honing chisels, knives and plane irons.
Eric Urani, Adah, PA