Insert nose radius

​The nose radius, RE, on the insert is a key factor in turning operations.
Selection of nose radius depends on the:
  • Depth of cut, ap
  • Feed, fn
and influences the:
  • Surface finish
  • Chip breaking
  • Insert strength



Small nose radius

  • Ideal for small cutting depth
  • Reduces vibration
  • Less insert strength

Large nose radius

  • Heavy feed rates
  • Large depths of cut
  • Strong edge
  • Increased radial forces

​The radial forces that push the insert away from the cutting surface become more axial as the depth of cut increases, preferable is to have more axial forces instead of radial, which have a negative effects on the cutting action e.g. with more tendencing to vibration and bad surface finish with increased radial forces.

The nose radius also affects the chip formation. Generally, chip breaking improves with a smaller radius.

As a general rule of thumb, the depth of cut should be greater than or equal to 2/3 of the nose radius, or 1/2 of the nose radius in the feed direction.

​For more information, see the different applications in Choice of application.