One of my cats used to want to sharpen claws on the end of the couch. I purchased a cheap scratching post at Walmart and placed it right in front of the spot she was working on. It worked like a charm and she transferred to the scratching post. I just left it there for a few months and then moved it a few feet away and she followed it. Had not more problems. I think they prefer the post to the pad because it duplicates scratching on the trunk of a tree.
I also rubbed some catnip into the base of the scratching post.