one more thing, it should be foldable
Depends on the knife blade itself. What have you got ?
It's not really a knife but actually a part of a garden grass cutter.it was blunt, but i managed to sharpen it.
Select your material, cut it to shape, sand it to finish, pin it to your knife frame. For any more assistance, you'll need to provide more of a description of what you're trying to accomplish.