Throwaway insert

A throwaway insert comprising:

• a base having an upper surface, a lower surface, and a plurality of side surfaces that connect the upper surface to the lower surface, the base being provided with a recess at a corner portion at which the upper surface crosses two side surfaces of the plurality of side surfaces;
• and
• a cutting edge member joined to the recess, wherein
• the cutting edge member includes
• a rake face,
• a flank face extending to cross the rake face,
• a first connecting face connecting the flank face to one side surface of the two side surfaces and extending to cross the rake face,
• a second connecting face connecting the flank face to the other side surface of the two side surfaces and extending to cross the rake face, and
• a first ridgeline formed by the rake face and the flank face and serving as a cutting edge,
• the rake face includes
• a main surface extending along the upper surface, and
• a first chamfer provided at an edge tip portion of the cutting edge member, the edge tip portion including an extreme tip portion of the cutting edge member,
• the cutting edge includes a first cutting edge part constituted of a first ridgeline part formed by the first chamfer and the flank face,
• in a plan view from the upper surface of the base, the flank face, the first connecting face, and the second connecting face are located external to the base,
• the first chamfer is inclined relative to the main surface so as to increase a thickness of the cutting edge member as the first chamfer is closer to the main surface,
• a second ridgeline formed by the rake face and the first connecting face crosses the first ridgeline at an obtuse angle, and
• a third ridgeline formed by the rake face and the second connecting face crosses the first ridgeline at an obtuse angle.