35mm CNC Drill Bit - 1mm Thin Wall Thickness for Drilling of Granite and Engineered Stone DUAL FITTING35mm CNC Diamond Drill Bit 1mm Thin Wall for Granite & Engineered Stone Precision engineered with a 1mm thin wall, this vacuum brazed diamond drill bit is designed for clean, efficient drilling through granite, engineered stone, marble, and concrete. The continuous rim provides smooth cuts while protecting the steel core. Dual Fitting: 1 2" Gas and internal M14 thread for compatibility with both CNC machines and handheld tools Thin Wall Design: 1mm