A facing head includes a fixed part, couplable with a head of a machine tool via an interface plate and a rotary part, wherein a compartment is placed internally to which drive means and measurement means are housed for driving and measuring a radial slide supported by the rotary part so as to close the compartment, and at least one electric collector for controlling the drive means and measurement means. A continuous gasket contacts the radial slide and a fluid collector supplies the compartment with pressurized air to seal the compartment. The fluid collector includes a rotary portion with first fluid routes, and a fixed portion integral with the fixed part of the facing head with second fixed fluid routes together supplying the rotary part with a coolant, supplying the compartment with pressurized air, and transporting the oil for locking the radial slide.

A facing head (1) is here described comprising a fixed part (4), couplable with a head of a machine tool (2) via an interface plate (3), a rotary part (5), wherein a compartment (35) is placed internally to which drive means (100) and measurement means (101) are housed for driving and measuring a radial slide (6) which is supported by the rotary part (5) so as to close the compartment (35), and at least one electric collector suitable for transmitting the electrical signals for controlling the drive means (100) and measurement means (101) used for driving and measuring the radial slide (6). The facing head (1) comprises a continuous gasket (40), which is configured in such a way as to completely make contact with the radial slide (6) and is housed inside a respective recess (34) which externally surrounds the compartment (35), and a fluid collector, which is suitable for supplying the compartment (35) with pressurized air, so that the pressure inside the compartment (35) is higher than the atmospheric pressure, so as to seal the compartment (35). The fluid collector comprises a rotary portion (22), which is integral with the rotary part (5) of the facing head (1) and comprises first fluid routes (43) internally thereto, and a fixed portion (23), which is integral with the fixed part (4) of the facing head (1) and comprises, internally thereto, second fixed fluid routes (45) coupled with the first fluid routes (43) to supply the rotary part (5) with a coolant, to supply the compartment (35) with pressurized air, and to transport the oil necessary for automatically locking the radial slide (6).

A machining device for machining the lateral surface of an approximately cylindrical object in portions thereof includes a chain for annularly surrounding the object to be machined. The chain consists of at least two hingedly connectable chain links, one of which is a tool holder having at least one tool for machining the lateral surface. The device also includes support rollers for rolling on the lateral surface. The at least one other chain link is a chain connecting link. The chain links are connectable in such a way that they form a closed chain ring around the object to be machined. The machining device further includes a feed adjuster capable of reversibly adjusting an axial position of facing ends of two chain links parallel to the axis of the closed chain ring relative to each other.