Description Commonly used to pre-drill holes for hardware using screws (particularly hinges), these self-centering drill bits are easy to adjust. The set screw in the barrel body is used to adjust the drill bit projection. Travel of the spring-loaded portion of the barrel determines the maximum pre-drill depth: the 5/64” and 7/64” bits have 3/8” of travel, and the rest have 1/2". The set includes the three smallest bit sizes. 1/4" dia. shanks for 5/64" to 9/64" bits, 5/16" dia. for 11/64" to 1/4", and 3/8" for 5mm. Nickel-plated steel construction. Includes a HSS drill bit. The 5/64” drill is for #3 and #4 screws; the 7/64” drill is for #5 and #6 screws; the 9/64” drill is for #8 to #10 screws; the 11/64” drill is for #12 screws; the 13/64” drill is for #14 to #16 screws; and the 1/4" and 5mm drills are for shelf supports.