A cutting insert having two end surfaces and a peripheral surface, the end surfaces located on opposite sides of a mid-plane, each end surface having three primary apexes and three secondary apexes. Six cutting portions are formed along the intersection of the peripheral surface and the end surfaces. Each cutting portion has a first cutting edge and a second cutting edge extending transversely thereto. A ramping cutting edge extends between the second cutting edge of each cutting portion and the first cutting edge of an adjacent cutting portion. The peripheral surface has a clearance surface extending from each of the second cutting edges towards the mid-plane. The abutment planes of the insert are parallel to the mid-plane. Each of the first cutting edges lies between an adjacent abutment plane and adjacent primary apex.