9/64" Diameter, 12" overall length, Aircraft Extension Drill .1406 decimal equiv. These 12" high speed steel aircraft extension drills are manufactured to National Aerospace Standard 907. 135 degree split point is self-centering and reduce thrust. Ideal for drilling in mild steels where extra length for reach is required. They have a black oxide surface treatment that is abrasion resistant, reduces chip welding and improves chip flow. Sizes smaller than 1/16 have the standard 118 degree standard point.