Drill America D/ASTCO3/4 3/4" Cobalt Heavy Duty Split Point Stub Drill Bit, D/ASTCO3/4Drill America D ASTCO3 4 3 4" Cobalt Heavy Duty Split Point Stub Drill Bit, D ASTCO3 4 Screw machine drills (also know as stub or stubby drills) are manufactured to Aerospace Standard 907. The 135 degree 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 drills are popular in the automotive and