Quick Change Hole Saw Arbor 7/16", Minimum Chuck Size 1/2". The best arbor in the industry ensures a solid connection without any gaps or wobbling. Arbors include replaceable, high-speed steel pilot drill. Pilot drills have unique split-point tip design. Use with Greenlee bi-metal hole saws, recessed light holesaws and carbide-grit hole saws (carbide-tipped pilot drill sold separately). Can be used with Greenlee #901 or #904 bit extensions.