Cutting insert for cutting, milling or drilling of metal, a tool holder and a tool provided therewith

A cutting insert for cutting, milling or drilling of metal comprising a sensor arranged to detect a predetermined wear of the cutting insert caused by operation thereof on a metal work piece, the sensor including at least two contact regions through which the sensor is connectable to external measuring circuitry, the sensor defining an open circuit having at least two leads, which are connected to a respective of the at least two contact regions, wherein each lead presents a respective free end, the free ends being spaced by a distance therebetween and from a cutting edge of the insert such that, upon the predetermined wear caused by the operation of the cutting insert on the metal work piece, the free ends of the leads become directly electrically interconnected to each other by the metal work piece or by a chip resulting from the operation of the cutting insert on the metal work piece.