Definitely a new ruler. I learned in a workshop by Marti Michel. Press down when cutting not sideways. Sounds simple. But when she said it I realized when I cut, I was pressing to the side and the upper part of the cut was slipping. Sandpaper dots help too. Also, when cutting that 24 inches, walk you "holding" hand up don't put your hand in one spot and then run the cutter up the length, it will be wonky.