7 pc Universal Barrel Trimming System Here’s a complete barrel trimming system. An essential step for making a quality pen project is to square the end of your pen blanks and pen tubes prior to final pen kit assembly. Our system includes cutting shafts that will fit into a drill chuck or lathe chuck – the shaft will clean the glue from the tubes and act as a pilot for the 3/4" squaring cutter. This complete system includes: • 7mm, 8mm, 3/8", and 10mm pilot shafts • 3/4" squaring cutter , allen wrench and instructions