Abstract: The device comprises a sectional carrier of closed cross section with a circular bed, a base and channels of distribution and return of oil. A guiding element comprising at least one guiding tube enclosing a bar stock to be machined and a push-piston is removably secured on the bed. The distribution channel communicates through radial openings with the guiding element for delivering to the latter oil under pressure which creates a hydrodynamic bearing supporting the bar stock when the latter is set into rotation by the head stock of the lathe. The sectional carrier has a great rigidity and stability which permits very high speeds of rotation of the bar stock to be machined. The return of oil by closed channels of the sectional carrier is protected against external contamination by impurities or dust.

Abstract: The device comprises a distributor with switching valves and individual circuits of hydraulic fluid under pressure and of vacuum, the switching valves permitting to connect the guiding tubes either to the circuit of fluid under pressure or to the circuit of vacuum. The guiding tube which encloses a remnant of a bar stock in which a last piece is machined is set under vacuum for retracting the feeding piston of this guiding tube toward the rear part of the device in an extension tube during the indexing of the barrel at the time of machining the last piece. This permits to supress the unproductive time normally necessary for retracting the feeding piston of the guiding tube in which a new bar stock to be machined must be introduced.