#13 HSS Threaded Shank Countersink (5/8") 12" Cobalt Aircraft Fractional Drills and they provide a smooth

and they provide a smooth finish on materials such as aluminum

as well as a 3/4" reduced shank that can be used in a wide range of tool-holding systems

They are built to work well with a wide variety of materials in the iron and steel families

SDS-Plus Carbide Tipped Drill Bits are designed for drilling stone or concrete

#13 HSS Threaded Shank Countersink (5/8") 12" Cobalt Aircraft Fractional Drills and they provide a smoothSpecifications PILOT SIZE #13 DECIMAL EQUIVALENT . 1850" BODY DIAMETER 5 8" MATERIAL HIGH SPEED STEEL THREAD SIZE 1 4 28 CUTTING ANGLE 100 SUGGESTED PACK QTY 1 Threaded countersink cutters can be used in adjustable or micro stop countersinking tools with a 1 4 28 threaded drive. They are made from high speed tool steel, precision ground to exact tolerances, and form relieved to ensure a 100 countersink angle concentricity.