Impact drill insert with frustum cutters

An improved impact drill insert with frustum cutters and adapted to be simultaneously rotated and reciprocated and comprising, in combination:

• an insert body member having a shank portion, a cutting head portion and a central axis;
• a pilot drill comprising one of a twist drill and a spade drill mounted on said cutting head portion and aligned with said central axis and having a preselected pilot drill axial length;
• a first plurality of frustum cutters in a first array mounted on said cutting head portion of said insert body member and said first plurality of frustum cutters having corresponding impact/cutter portions lying in planes perpendicular to said central axis and spaced axially from said pilot drill;
• each of said frustum cutters in said first plurality in said first array having an axis at a predetermined skew angle with respect to said central axis and each of said frustum cutters in said first plurality radially spaced from said central axis;
• a second plurality of frustum cutters in a second array mounted on said cutting head portion of said insert body member and said second plurality of frustum cutters having corresponding impact/cutter portions lying in planes perpendicular to said central axis and spaced axially from said pilot drill;
• each of said frustum cutters in said second plurality in said second array having an axis at a predetermined skew angle with respect to said central axis and each of said frustum cutters in said second plurality radially spaced from said central axis and radially spaced from said first plurality of frustum cutters in said first array;
• each of said frustum cutters in said first plurality of said frustum cutters in said first array spaced a first radial distance from said central axis and spaced a first axial distance from said pilot drill;
• each of said frustum cutters in said second plurality of said frustum cutters in said second array spaced a second radial distance from said central axis and said second radial,distance is greater than said first radial distance, and spaced said first axial distance from said pilot drill;\
• said axis of each of said frustum cutters in said first plurality of frustum cutters at a first skew angle with respect to said central axis and said axis of each of said frustum cutters in said second plurality of frustum cutters at a second skew angle with respect to said central axis;
• said corresponding impact/cutter portions of each of said frustum cutters in said first array and each of said frustum cutters in said second array lie in a plane perpendicular to said central axis.