Counterbores N with a diameter of 50mm and larger are all made with a driving lip. These sizes should be used in the appropriate type M toolholder.

Dimensions (mm) N, NA & W
Counterbores N, and NA with Ø of 50 mm and larger are all made with a driving lip. These sizes should be used in the appropriate type M toolholder
d: 14.0; d1: 6.0; L: 48.0; L1: 28.0.