Cutting insert and shoulder millng tool

A cutting insert for a shoulder milling tool, the cutting insert comprising:

• a body having a trigonal shape and a median plane extending through the body;
• a first surface, an opposite second surface, and a circumferential surface extending between the first surface and the second surface, the first and second surfaces extending on opposite sides of the median plane;
• and
• at least one cutting edge extending along an intersection between the first surface and the circumferential surface, the at least one cutting edge, as seen in a view towards the first surface, extending along a corner of the cutting insert, wherein the at least one cutting edge includes a main cutting edge, a corner cutting edge, and a surface-wiping secondary cutting edge, wherein the main cutting edge adjoins the corner cutting edge, and the corner cutting edge adjoins the surface-wiping secondary cutting edge, the surface-wiping secondary cutting edge being inclined in relation to the median plane such that a distance to the median plane decreases in a direction toward the corner cutting edge, and wherein the corner cutting edge, as seen in a side view along the median plane and towards the main cutting edge, includes a concave curve, wherein the first surface includes a flat centre surface transforming into an inclined main rake face adjacent to the main cutting edge, wherein an entirety of the main cutting edge and the inclined main rake face extends at a greater distance from the median plane than the flat centre surface.