Patent ID: 6039515
Filing Date: 2000-03-21
Classification: B23B,Y10S,Y10T

Abstract:
A drill comprising a shank, a central insert, and a peripheral insert;the shank defining a central axis of rotation and having a central pocket receiving the central insert, a peripheral pocket receiving the peripheral insert, a pair of chip flutes extending rearwardly in an outer periphery of the shank from respective ones of the pockets for conducting chips cut by the central and peripheral inserts, respectively;the peripheral insert including a first operative cutting edge projecting laterally outwardly beyond the shank to form a diameter of a hole cut by the drill;the central insert being substantially square and including a second operative cutting edge overlapping the first operative cutting edge at an overlap region spaced radially from the axis of rotation, the second operative cutting edge extending inwardly past the axis of rotation, the central insert forming a rake surface adjacent to the second cutting edge, the rake surface including a first portion disposed at the axis of rotation and a second portion disposed at the overlap region, the second portion having a larger rake angle than the first portion.