Cutting insert for turning and milling

A cutting insert comprises first and second polygonally-shaped main faces arranged substantially parallel to one another, and a side face structure interconnecting the first and second main faces to define a peripheral edge. At least the first main face includes at least one projection extending to the peripheral edge, the projection formed by: a portion of the first main surface (defining a relief surface), a portion of the side face structure (defining a rake surface), and a portion of the peripheral edge (defining a cutting edge). The insert includes support surfaces defined by a portion of the second main face, and by portions of the side surface structure other than the rake surface.