My significant other decided he didn't need a quilting ruler, he could just use a plain old plastic ruler to help me cut . He soon learned, the hard way, that the rotary cutter jumps over the edge. Moral of story, he cut the tip, skin deep only, thank goodness, of his finger off, but it took forever to heal for exactly the same reason as above, continued to bleed/seep for days. Now I truly keep my rotary cutters out of his reach. Men are like kids.