ISO International Standard

ISO 3438:2013 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.

ISO 3438:2013 complements ISO 2306.