Am I just dreaming but did I read somewhere about a ruler that has an edge on it so that it will sharpen the blades as they are rolled along the edge? I could sure use that. I've been having trouble with blades "perforating" fabrics. Have changed to a new blade but still there will be a few threads not cut through. I bought a new mat, thinking that might be the problem, but that didn't solve the situation. Still have a few threads that will not give up!