TWIST DRILL WITH CURVILINEAR LIP Russian patent published in 2014 - IPC B23B51/02 

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and can be used at drilling holes, for example, in cast iron. Drill comprises cutting edge made to ensure invariable wear of its points at hole processing. Cutting edge projection to plane to perpendicular to drill rotational axis is defined depending on polar angle of current point of cutting edge projection to the plane perpendicular to drill rotational axis. Said polar angle is counted from projection initial point in direction opposite that of drill rotation, radius of circle wherein belongs the current point of cutting edge protection to the plane of drill rotational axis, radius of circle wherein belongs the initial point of cutting edge protection to the plane of drill rotational axis, and drill core radius.

EFFECT: higher hardness of helical drill.

1 tbl, 3 dwg