3664HSSM HSS Heavy Duty Split Point Screw Machine Stub Drill Bit, Size: 9/16” Screw Machine drill bits are manufactured to National Aerospace Standard 907. 135° split point is self-centering and reduces thrust. Ideal for portable or machine drilling. Short, rugged construction performs well in a broad range of materials in the iron and steel families.Screw Machine drill bits are popular in the automotive and construction industries. Screw Machine drill bits are often used in screw machine setup where spindle clearance is limited.