DRILL Russian patent published in 2015 - IPC B23B51/00 

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and can be used for drilling with the help of hand-held drill, drilling machine or the like. Claimed drill has two cutting edges arranged in symmetry about axis of rotation. Said drill has recess at said cutting edges shaped to curved line extending from the end of crosswise edge to outer peripheral side of the drill. Major cutting edge extends from the end of recessed cutting edge in external direction to drill peripheral side of the drill if seen from the drill end side. Recessed cutting edge features U-like shape with inclination to drill axis if seen from drill front side. Drill face angle composed by the major cutting edge is larger than that composed by recessed cutting edge except for section located below crosswise cutting edge.

EFFECT: efficient removal of chip, lower resistance to drilling, higher efficiency.

8 cl, 19 tbl, 16 dwg