DRILL Russian patent published in 2012 - IPC B23B51/00 

FIELD: process engineering.

SUBSTANCE: proposed drill comprises two-edge cutting plate, base with cutting plate secured on base surfaces and furnished with web and chip separation elements. Drill incorporates drilling diameter two-side adjustment device and centering ring. Note here that two-edge plate is secured by cone while its cutting edges may form two parts with transition there between and directed upward, toward periphery, and downward relative to main secant surface. Said transition is made up of ledge making centering surface to divide cutting edge into starting part and reaming part. Note here that chip separation elements represent steps made on rear and front surfaces of cutting plate. Note also that front surface of starting part, above reaming part front surface, may make a start. Note also two-edge plate has two side edges and two work parts, thrust and centering surfaces. Note that drilling diameter two-side adjustment device consists of adjusting screw in contact with adjusting plate fitted in body via slots and hole and locked by screw, and furnished with guides. Note that drilling diameter two-side adjustment device comprises adjustable elements arranged on reaming part and pressed by screws via holes with diameter exceeding that of screws. Spring is connected with adjusting plate on the side opposite adjusting screw.

EFFECT: higher precision, better chip crushing, reduced vibration of cutting plate.

4 cl, 9 dwg