DRILLING TOOL (VARIANTS) WITH CHANGEABLE CUTTING TIPS AND CHANGEABLE CUTTING TIPS (VARIANTS) FOR SUCH DRILLING TOOL Russian patent published in 2008 - IPC B23B51/00 

FIELD: working materials by cutting, built-up cutting tools.

SUBSTANCE: tool includes main part, two changeable cutting tips inserted to mounting seats with possibility of changing, turned one to other by their central angles while remaining free central gap and having main cutting edge passing from radial outer guiding chamfer till central angle and also having front and back surfaces meeting in region of main cutting edge for forming cutting wedge. Said main cutting edges in region of central bent portion of cutting edge are mutually complemented passing to bridge interrupted by central gap. Changeable cutting tips are provided with through opening for fastening member. In order to reduce risk of breaking cutting tips in their central region and to improve possibility for guiding tool, cutting tips have on back surface inclined guiding chamfer passing from central part of cutting edge till central angle of tip. Back surfaces in region of guiding chamfers are negatively inclined in direction of feed towards central gap while they are mutually complemented in the form of funnel. Guiding chamfer is inclined in direction of respective supporting surface and central part of cutting edge and opposite edge of tip are convergent in central angle of tip.

EFFECT: reduced risk of breaking cutting tips, improved possibility for guiding tool.

103 cl, 11 dwg