SPM-13 : 66460 Description: Super Premium Mechanic Length Drill Set 13 Pieces 135° Split Point 3 Flats on Shank 3/16" and larger Type: 250-UB Sizes: 1/16 thru 1/4 by 64ths No Photo Available Special Hi-Molybdenum tool steel. 135° split point for fast penetration and accurate starting without center punch. Precision ground point, flutes, body, clearance and drill diameter for the ultimate in accuracy and performance. Body and clearance are gold surface treated for maximum lubricity. Heat treated at 2185° F and then nitro-carburize finished at 950° F to be measurably harder than high speed steel. Space age nitro-carburized steel withstands substantially higher drilling temperatures while maintaining sharpness. Especially designed for hand held drills. Flats on shank give positive chuck grip (3/16 and larger). Recommended for use in work hardening grades of stainless steel and other hard metal drilling applications.