This International Standard specifies the dimensions of subland twist drills with Morse taper shanks and cylindrical shanks for holes prior to tapping screw threads. The drills are designed to produce holes prior to tapping metric threads (coarse pitch series) over a selected range of: — M8 to M30 for subland twist drills with Morse taper shanks; — M3 to M14 for subland twist drills with cylindrical shanks. This International Standard complements ISO 2306. The relationship between the symbols of this International Standard and those according to the ISO 13399 series is given for information in Annex A.