Includes 7mm Pilot Shaft, 5/8" Carbide Cutter Head, and Allen Wrench. Square the end of your pen blanks and pen tubes prior to turning on the lathe and pen kit assembly. Shaft acts as a pilot for the cutting head and helps remove excess glue from the tube. Shaft will fit into a drill chuck or lathe chuck. Barrel trimming and squaring is an essential step in penturning projects to ensure a proper fit between the pen kit hardware parts and the turned blank.