taper shank twist drill is the most widely used hole making tool, usually ranging in diameter from 8 (5/16")to 100 (4")mm, it is mainly composed of the working part and the shank.  The working part has two spiral-shaped grooves, shaped like a twist, hence the name.  Unlike the straight shank twist drill, the taper shank twist drill has a taper.  Different specifications of twist drill, with different Morse taper .

METRIC SIZES DIN345  ,LONG SERIES DIN341,EXTRA LONG SERIES DIN1870/1

FRACTIonAL SIZES ANSI B94

General purpose 118° point, heavy duty 135° notched point ,extra long series could be used in deep hole or long reach drilling applications in many kinds of materials.