Rotary diecutting has always had the limitation of only being able to crease from the inside of the sheet. This has made reverse folds difficult at best. National’s 5 Tooth Slit Score is designed to cut through the inner liner and medium, without cutting through the outer liner. The trick is a combination of sharp pointed teeth and choosing the proper relationship between the cutting rule and the slit score rule. We recommend using a slit score approximately 1/16” (1.5mm) lower than the highest cutting rule being used in the die. While this rule is designed not to cut through the outer liner, it is possible that the points may pierce the outer liner. This could be the result of not being able to precisely control the rule penetration. Also available in a 6 tooth version.