Dimensions Technical data of Twist Drill Bits

Drill Diameter
  • The values indicated in the relevant dimensional standards apply in respect of the diameter of Twist Drills
  • Test Point : on the leads at the corners(see Fig.1 )
  • Test equipment: micrometer
Tapering of Diameter
  • The diameter of twist drills usually reduces from the drill tip towards the shank in the area of the flute
  • Test values : the taper on diameter amoutns to 0.02 to 0.08mm over a length of 100mm
  • Test point: at the outside diameter on the land
  • Test equipment : micrometer and indicating measuring instruments
Point Angle
  • Test value : 118° or 135°
  • Test point : at the cutting edges ( see Fig.2)
  • Test equipment: Univeral bevel protractor indicating measuring instruments

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