Drill bit for solid hard metal-driller for chip removal of e.g. spheroidal graphite, has main free surface forming clearance angle, where factor of clearance angle at region of transversal edge is larger than angle at outer circumference

摘要

The drill bit has main cutting edges, which are connected together by a transversal cutting edge (105). A main free surface (109) is attached to the main cutting edges and forms increasing clearance angle from an outer circumference of the drill bit into an axial direction. A factor of 1.2 to 2.2 clearance angle at a region of the transversal cutting edge is larger than the clearance angle at the outer circumference. Adjacent free surfaces are attached to the main free surface. The main cutting edges form a central section (101b) at a projection and a profile. An independent claim is also included for a method for manufacturing a drill bit.