Abstract: A tool holder assembly, having a central tool holding shaft (1) provided, on the one hand, with a mounting cone for securement in a machine tool spindle and, on the other hand, on the side opposite the cone, with an intermediate cylindrical body provided at its forward portion with securement structure for a tool. It is provided also with a feeler device (2) centered on the central shaft (1) and guided in translation on this latter, with lubricating structure and with cleaning structure for the machining region at the location of application of the feeler device (2).

Abstract: The present invention relates to a boring head constituted by a body (1) provided with a radial piston (2) for reception of a boring tool (3) gripped by means of a screw (4), said piston (2) being adjustable in position by means of a micrometric screw (5), characterized in that the body (1) is provided also with a slide block (6) effecting the guidance, the orientation and an end-of-movement abutment for the piston (2) for reception of the boring tool (3) and with a balancing device (7) with independent counterweights (8 and 9).