Abstract: Milling tool has a tool body with a fixing end, an opposite outer end, and a peripheral surface. The tool body comprises a large number of separated seats arranged at the peripheral surface one after the other along a helix line having a constant pitch. Corresponding large number of replaceable milling inserts comprise an under side, an opposite upper side forming a chip surface, a circumferential edge side, and two pairs of main cutting edges. The chip surface extends in an extension plane that comprises the main cutting edges. Each seat receives one of the milling inserts and comprises a support surface allowing support to the milling insert projecting from the tool body for cutting engagement with a gash of the workpiece. The chip surface extension plane of each milling insert has a normal parallel to the tangent of the helix line where the same intersects the extension plane.