Patent ID: 8764352

Claim:
A three-way indexable throwaway tip for deep-hole drilling comprising: a plate body having three convex cutting sections rotationally spaced apart from one another by 120 degrees; a plate corner between each pair of adjacent convex cutting sections; each convex cutting section comprising a blade edge between a first plate corner and an adjacent second plate corner, the blade edge comprising: an inner blade edge linearly extending between the first plate corner and a section apex; and an outer blade edge extending between the section apex and the adjacent second plate corner, the outer blade edge being longer than the inner blade edge and comprising a peak-side outer blade edge portion and a corner-side outer blade edge portion, the peak-side outer blade edge portion forming an obtuse angle with the corner-side outer blade edge portion, the peak-side outer blade edge portion being connected to the section apex, the corner-side outer blade edge portion being connected to the adjacent second plate corner; wherein, in a front view of the throwaway tip: an adjacent inner blade edge extends along a longitudinal imaginary reference line (L) between the adjacent second plate corner and an adjacent section apex; a transverse imaginary line (e) perpendicular to the longitudinal imaginary reference line (L) contains the section apex; the inner blade edge forms an inner blade edge angle (a) with the transverse imaginary line (e); the peak-side outer blade edge portion forms a first angle (β 1 ) with transverse imaginary line (e); the corner-side outer blade edge portion forms a second angle (β 2 ) with transverse imaginary line (e); and the second angle is greater than the first angle; and wherein: the adjacent inner blade edge, and a second corner-side outer blade edge portion which belongs to a second convex cutting section and is connected to the first plate corner, are parallel to one another.