DRILL CASE AND DRILL Russian patent published in 2021 - IPC B23B51/04 

FIELD: drilling.

SUBSTANCE: group of inventions relates to the processing of materials by cutting; it can be used when drilling metals on various machines with a dimeter D. Drill case (4) and drill (2) are disclosed. Drill case (4) has axis (10) of rotation and contains peripheral chip groove (22) extending along the perimeter of drill case (4). The cross section of the peripheral chip groove has central line (26’) continuing in a plane perpendicular to the axis of rotation and passing through axis (10) of rotation. The cross section of the peripheral chip groove has radially inner side (32) extending perpendicular to central line (26’), and first and second lateral sides (34, 34’) connecting to the radially inner side. Radially inner side (32) has length L1 in the range from L1=0.95 x D/4 to L1=1.2 x D/4. Each of first and second lateral sides (34, 34’) has length LS1, LS2 in the range from D/4 to 1.3 x D/4. The first and second lateral sides diverge from each other in the direction radially outward from the radially inner side.

EFFECT: invention provides increased rigidity for bending and twisting.

17 cl, 3 dwg