Cut-off tool

The invention provides a cutoff tool that enables more narrow grooves to be produced in comparison with cutoff tools of conventional design. The tool consists of a holder 10 having a recess 12 in one side face 11 in which a cutting insert 13 is located and clamped by means of a centre screw 14 threadably engageable with the holder 10. According to the invention the insert 13 is of polygonal shape and provided with a protruding central portion 20, which is received in said recess 12 in the holder, whereas the remainder of the insert extends laterally from the holder for cutoff purposes. The protrusion 20 is polygonal in shape in correspondence with the shape of the insert but angularly offset therefrom.