If it is a single bevel, then it is like a wood chisel or a 'tanto' edge. Use a ink marker to cover the ground edge, then carefully stroke (with new file or wetstone). The ink will be worn by the stone/file.You want the ink to be worn completely across the factory bevel, so you are matching the factory angle. Many light stokes are better than a few big ones. Once you have a good edge-lightly stone the back (flat) of the edge just a few times to remove the burr formed from sharpening the front. Then hone lightly for final sharp edge. Make any sense?