We just got back from New Hampshire where I spent a couple of hours in Keepsake Quilting in Center Harbor, New Hampshire looking at all the notions that I only see in catalogs and online. I picked up a 9.5" square "the cutting Edge sharpening Ruler by Sullivan". It has a diamond carbide edge with helps keep the rotary blade sharp as you cut. I just started using it and I think it does work. My next purchase will be the 6" x 24" ruler. I have tried sharpening tools on my rotary blade and didn't like them. I hate throwing away a blade when it begins to skip - they cost so much and it seems like I am being wasteful. Has anyone used the Sullivan's sharpening ruler? What do you think?