TESTA DI ALESATURA

The boring head of a multiple-operation machine tool comprises a housing which is kinematically coupled to a spindle. This accommodates a carriage spring-biased against the housing. The carriage carriers a mandrel for a cutting tool and has an inclined surface to interact with an inclined surface of a rod arranged in the housing coaxially with the latter and kinematically coupled to a drive which moves the rod in the axial direction. The boring head incorporates a counterbalance comprising at least two pins received in through holes provided in the carriage. The holes are symmetrical in relation to the axis of rotation of the boring head and extend perpendicular to the axis. The pins are kinematically coupled to the rod so that they can reciprocate in the through holes of the carriage.