Question: You said you made it form high carbon steel, did you heat treat it or was it already hardened? Reason I ask is if it has been hardened you're not going to cut it with a file (or you shouldn't be able to). You'll need to get the bevel angle started with a belt sander taking care to keep it cool, not let it turn colors, thus removing the heat treatment.
If you sharpen them to something close to a 30 degree angle you can sharpen them with just about anything. Sharpening stone, Lansky setup...whatever.