Fuller Tapered Drill Countersink – Hex Shank

These unique bits perform three functions: drilling countersinks for heads, through holes for shanks, and pilot holes for screw threads in a single operation. The countersink head adjusts along the tapered drill bit to accommodate different screw lengths. To control exact countersink depth use  optional stop collars (not included) . Drills taper to allow pilot holes from 1/2″ deep (5) to 7/8″ deep (12). Countersink diameter is 3/8″ for 5-9 and 1/2″ for 10 & 12.