Some wafer thin dies may cut through thin felt. However, if you want to cut leather, chipboard or other thicker materials you will need to purchase the steel ruled dies. This machine accepts both types of dies and you will have to adjust the plates sandwich accordingly. Also, leather may be somewhat finicky because it all depends on the type of material the leather is backed up with. Some leather materials are back up with a soft fuzzy material and that would cut using a steel ruled die, some leather is backed up with a normally white material with threads going in all directions in order to provide strength to the leather and those are sometimes finicky. when it comes to the latter type of leather you are not going to know unless you get a sample and test it.