Spiral drill, has recess formed at drill bars in circumferential direction by respective two guide chamfers and limited by chamfers, while recess runs in axial direction into peripheral surface of working part of tool body

摘要

The drill has a chamber-like recess (8) staying in effective connection with a central coolant channel system boreholes (4) and formed by coolant channel system boreholes (10). The recess is formed at drill bars (5) in circumferential direction by respective two guide chamfers (9) and is limited by the chamfers, while the recess runs in axial direction into the peripheral surface of a working part of a tool body. The working part is designed without guide chamfers and the recess corresponds to axial length such as 2-5 times the drill diameter of the drill bit.