Patent ID: 6979153

Claim:
A deep-grooving chip-forming cutting insert comprising a rear mounting portion, a front cutting portion, and a pair of side walls; each side wall extending along the front and rear portions; the front cutting portion including a front end surface, a top surface, and a cutting edge disposed at a transition between the front end surface and the top surface and extending from one side wall to the other to define a cutting width; the cutting edge comprising a main portion, a pair of convexly curved first corner portions disposed at respective ends of the main portion, and a pair of convexly curved second corner portions offset rearwardly and outwardly with respect to respective first corner portions, wherein a step is formed between each first corner portion and its respective second corner portion; the main portion having a length as viewed in a direction perpendicular to the top surface, and which is at least 80% of the cutting width.