Assembly of a cutting insert and a tool holder

An assembly of a cutting insert and a tool holder,

• the cutting insert comprising an upper surface, a lower surface, a side surface, a cutting edge, and a mounting hole penetrating the upper surface and the lower surface, wherein
• the cutting edge includes a main cutting edge, a corner cutting edge extending from the main cutting edge, and a sub-cutting edge extending from the corner cutting edge,
• the side surface includes a main cutting edge flank surface and a sub-cutting edge flank surface,
• the main cutting edge flank surface includes a first main cutting edge flank surface extending from the main cutting edge, and a second main cutting edge flank surface extending from the lower surface,
• the sub-cutting edge flank surface includes a first sub-cutting edge flank surface extending from the sub-cutting edge, and a second sub-cutting edge flank surface extending from the lower surface,
• the first sub-cutting edge flank surface and the second sub-cutting edge flank surface together form a stepped portion, and
• the second sub-cutting edge flank surface protrudes from an imaginary plane extending from the first sub-cutting edge flank surface,
• the tool holder comprising a pocket portion in which the cutting insert is seated, wherein
• the pocket portion includes a first side mounting surface, a second side mounting surface, a recess portion positioned between the first side mounting surface and the second side mounting surface, and a bottom mounting surface,
• the recess portion includes a first recess portion in a direction away from the bottom mounting surface, and a recess surface portion that is stepped relative to the first recess portion and protrudes relatively further from a virtual extension plane of a surface of the first recess portion, and
• the first recess portion and the recess surface portion form a second locking jaw,
• wherein the second main cutting edge flank surface of the cutting insert is supported on the first side mounting surface, and another second main cutting edge flank surface of the cutting insert is supported on the second side mounting surface, and the lower surface is supported on the bottom mounting surface, and
• the first sub-cutting edge flank surface forms a predetermined gap with the recess surface portion, in which a first locking jaw protrudes into a space formed in the first recess portion.