Leo?s paper drills are made of a high-tensile metal alloy and are subject to rigorous quality control. Using our wax paper and drill back-up made from special cardboard ensure a long service life. Our paper drills fit in most oft he common paper drilling machines like Nagel, Hang, Dürselen, etc. Regarding the shaft diameter please note: paper drills with a shaft diameter up to 9mm fit in most of the paper drilling machines. From 10mm to 15mm diameter a bigger collet chuck is needed. From 16mm diameter on there is no need for a collet chuck. You will find more information in the instruction manual of your paper drilling machine.