HSS Straight Shank Twist Drills
Manufacturing process: Roll Forged or Fully Ground Material: F4341,4341,9341,M2,M42,M35 Point Angle: 118degree or 118/135 degree(Split Point) Flute: N or VA (Parabolic) Standard: DIN338 The twist drill is the most common type of drill. The shank of the drill is held by the machine tool, which in turn imparts a rotary motion. This shank may be straight or tapered. The body of the drill is typically made up of two spiral grooves known as flutes, which are defined by a helix angle that is generally about 30 degree but can vary depending on the material properties of the work piece. The point of the drill generally forms a 118 degree angle and includes a 10 degree clearance angle and chisel edge. The chisel edge is flat with web thickness of approximately 0.015 x drill diameter. This edge can cause problems in hole location owing to its ability to "walk" on a surface before engaging the work piece. In the case of brittle materials, drill point angles of less than 118 degrees are used, while ductile materials use larger point angles and smaller clearance angles.
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