Draper 56387 7/16" HEX Holesaw Arbor w HSS Pilot Drill for Holesaws 14 - 30mm. This Arbor is for use with 14-30mm diameter holesaws and is supplied complete with a 1/4" HSS pilot drill. It comes in a display carton. Specifications include: Pilot drill diameter N/A, Supported holesaw size 14 to 30mm. Draper Expert Quality, for use with 14-30mm diameter holesaws.