CMT 369.150.12 Hinge Boring Bit 15 x 70mm LH Made to Order and handheld routers where professional and handheld routers where professional two face finish quality is required in plywood Heavy gauge steel with a corrosion resistant coating 12 gauge construction paired with a G90 zinc galvanized finish means the connector is built to handle both the structural demands of high capacity loads and the moisture exposure common in masonry environments 2 Precision Ground Negatively Set Spurs (Z2) negatively ground geometry produces clean bore walls and a flat bottomed hole with minimal tear out this left hand rotation bit is the correct tool for European style concealed hinge installation on multi spindle CNC boring machines and compatible boring equipment