TOOL FOR DRILLING OF HOLES IN SOLID METAL Russian patent published in 2000 - IPC

FIELD: working of metals by cutting. SUBSTANCE: tool has main body containing chip flute and at least two cutting plates positioned on its end face at end of corresponding chip flute in respective hollow. Cutting plates are positioned at different radial distance on main body so that their operating sections are overlapped partially. Blades of cutting plates are formed by two cutting edges making up obtuse an angle at the top. Front surface of cutting blades is provided with chip removing ribs arranged near each other. They serve as sliding guides which are directed to cutting edges approximately perpendicularly and are outgoing arc-wise in direction of chips coming off radially inside with respect to their location towards zone of cutting plate side, close to drilling tool axis. EFFECT: improved removal of chips. 14 cl, 8 dwg