The invention relates to a rotating cutting tool, in particular a boring tool for use in machine tools. The cutting tool comprises at least one cutting insert (16'), designed as an indexable insert, that has an active main blade (26) located near a corner (25) of the insert, the outer end (28) of said blade defining a circular flight path radius (R) as the blade rotates, said blade penetrating into a work piece (32) at a pre-determined cutting depth (t) near a pre-formed round hole (30). Also provided is a secondary blade (36) that is disposed opposite to an advancing direction (34) and that aligns with the outermost end (28) of the main blade (26), the entire length of said blade having a smaller radius than the circular flight path radius (R) of the main blade (26), wherein a secondary blade free surface (38) aligns with the secondary blade opposite to the direction of rotation (37). A unique characteristic of the invention is that the secondary blade free surface (38) comprises a support part (40) disposed at a distance from the secondary blade (36), the peripheral radius of said part being larger than the circular flight path radius R of the active main blade (26) by an overshoot amount (Y).