A single-sided three-way indexable cutting insert having a positive basic shape and comprising: a material volume V F defined by the amount of material of the cutting insert; a rake surface; a base bearing surface located opposite the rake surface; an insert axis A I extending perpendicular to the base bearing surface and through a center of the insert, the insert axis A I defining: an upward direction Du from the base bearing surface towards the rake surface, a downward direction D D opposite to the upward direction Du, and an outward direction Do perpendicular to the upward and downward directions Du, D D and extending away from the insert axis A I; a cutting insert height Hi measurable parallel to the insert axis A I, from the base bearing surface to a highest point of the rake surface; a peripheral surface connecting the rake surface and base bearing surface; a cutting edge formed along an intersection of the peripheral surface and the rake surface, the cutting edge defining, in a view parallel to the insert axis A I, an imaginary edge circumscribed circle C E having an edge circumscribed diameter D E; and a screw hole opening out to the rake and base bearing surfaces (24, 26), the screw hole comprising: a screw hole bottom at an intersection with the base bearing surface; a screw hole top at an intersection with the rake surface; a void volume V s calculated as the volume of a void extending from the screw hole bottom to the screw hole top; and a hole circle C S defined, in a view parallel to the insert axis A I, at an intersection of the rake surface and the screw hole, the hole circle Cs having a hole diameter Ds; the base bearing surface defining, in a bottom view parallel to the insert axis A I, an imaginary base circumscribed circle C B having a base diameter D B; the peripheral surface comprising first, second, third, fourth, fifth and sixth side abutment surfaces (38A, 38B, 38C, 38D, 38E, 38F); the cutting edge, in a top view parallel to the insert axis A I, defining an edge inscribed circle C M having an edge inscribed diameter D M, the cutting edge comprising: exactly three main sub-edges (48A, 48B, 48C) and exactly three secondary sub-edges (47A, 47B, 47C), the main sub-edges (48A, 48B, 48C) alternating with the secondary sub-edges (47A, 47B, 47C) with a corner sub-edge (46, 46A, 46B, 46C, 46D, 46E, 46F) at each intersection between the main and secondary sub-edges; wherein: the base circumscribed diameter D B is smaller than the edge circumscribed diameter D E; characterized in that: a volume ratio of the void volume Vs to the material volume V F fulfills the condition: V S / V F ≥ 0.30; and the edge circumscribed diameter D E fulfills the condition: D E < 6 mm. a material volume V F defined by the amount of material of the cutting insert; a rake surface; a base bearing surface located opposite the rake surface; an insert axis A I extending perpendicular to the base bearing surface and through a center of the insert, the insert axis A I defining: an upward direction Du from the base bearing surface towards the rake surface, a downward direction D D opposite to the upward direction Du, and an outward direction Do perpendicular to the upward and downward directions Du, D D and extending away from the insert axis A I; a cutting insert height Hi measurable parallel to the insert axis A I, from the base bearing surface to a highest point of the rake surface; a peripheral surface connecting the rake surface and base bearing surface; a cutting edge formed along an intersection of the peripheral surface and the rake surface, the cutting edge defining, in a view parallel to the insert axis A I, an imaginary edge circumscribed circle C E having an edge circumscribed diameter D E; and a screw hole opening out to the rake and base bearing surfaces (24, 26), the screw hole comprising: a screw hole bottom at an intersection with the base bearing surface; a screw hole top at an intersection with the rake surface; a void volume V s calculated as the volume of a void extending from the screw hole bottom to the screw hole top; and a hole circle C S defined, in a view parallel to the insert axis A I, at an intersection of the rake surface and the screw hole, the hole circle Cs having a hole diameter Ds; a screw hole bottom at an intersection with the base bearing surface; a screw hole top at an intersection with the rake surface; a void volume V s calculated as the volume of a void extending from the screw hole bottom to the screw hole top; and a hole circle C S defined, in a view parallel to the insert axis A I, at an intersection of the rake surface and the screw hole, the hole circle Cs having a hole diameter Ds; the base bearing surface defining, in a bottom view parallel to the insert axis A I, an imaginary base circumscribed circle C B having a base diameter D B; the peripheral surface comprising first, second, third, fourth, fifth and sixth side abutment surfaces (38A, 38B, 38C, 38D, 38E, 38F); the cutting edge, in a top view parallel to the insert axis A I, defining an edge inscribed circle C M having an edge inscribed diameter D M, the cutting edge comprising: exactly three main sub-edges (48A, 48B, 48C) and exactly three secondary sub-edges (47A, 47B, 47C), the main sub-edges (48A, 48B, 48C) alternating with the secondary sub-edges (47A, 47B, 47C) with a corner sub-edge (46, 46A, 46B, 46C, 46D, 46E, 46F) at each intersection between the main and secondary sub-edges;