A boring bar actuatable by a centrifugal force generated by rotation of the boring bar about a rotation axis, comprising: - a coupling portion to couple the boring bar to a spindle for rotating the boring bar about the rotation axis, the coupling portion comprising a supply inlet for connecting the boring bar to a fluid supplying circuit; - a receiving portion to receive a cutting insert cartridge in a cutting position or a non-cutting position; - an actuating device configured to place the cutting insert cartridge received in the receiving portion either in the cutting position or in the non-cutting position, the actuating device having an actuating inlet and a non-actuating inlet, the actuating device being configured to place the cutting insert cartridge: • in the non-cutting position when the actuating inlet is supplied with a fluid, and • in the cutting position when the non-actuating inlet is supplied with a fluid or when neither the actuating or the non-actuating inlet is supplied with a fluid; - a fluid connecting circuit for fluid connection between the supply inlet and either the actuating inlet or the non-actuating inlet, the fluid connecting circuit comprising a control element movable between: • a first control position wherein the supply inlet is in fluid connection with the actuating inlet, and • a second control position in which the supply inlet is in fluid connection with the non-actuating inlet; wherein the control element is configured to be moved from the first control position to the second control position when the centrifugal force generated by the rotation of the boring bar about the rotation axis reaches a centrifugal force threshold, the control element being configured to be moved from the second control position to the first control position when the centrifugal force generated by the rotation of the boring bar about the rotation axis is below the centrifugal force threshold, wherein the boring bar comprises at least two receiving portions to receive a plurality of cutting insert cartridges distributed on the boring bar about the rotation axis, characterised in that a lubrication orifice is formed in each receiving portion, the non-actuating inlet is in fluid connection with each lubrication orifice to discharge the fluid on a cutting insert mounted on each cutting insert cartridge received in the receiving portions, wherein the non-actuating inlet comprises a circular groove, the actuating device further comprising a plurality of lubrication channels, each lubrication channel extending from the circular groove to a lubrication orifice formed in a receiving portion. - a coupling portion to couple the boring bar to a spindle for rotating the boring bar about the rotation axis, the coupling portion comprising a supply inlet for connecting the boring bar to a fluid supplying circuit; - a receiving portion to receive a cutting insert cartridge in a cutting position or a non-cutting position; - an actuating device configured to place the cutting insert cartridge received in the receiving portion either in the cutting position or in the non-cutting position, the actuating device having an actuating inlet and a non-actuating inlet, the actuating device being configured to place the cutting insert cartridge: • in the non-cutting position when the actuating inlet is supplied with a fluid, and • in the cutting position when the non-actuating inlet is supplied with a fluid or when neither the actuating or the non-actuating inlet is supplied with a fluid; • in the non-cutting position when the actuating inlet is supplied with a fluid, and • in the cutting position when the non-actuating inlet is supplied with a fluid or when neither the actuating or the non-actuating inlet is supplied with a fluid; - a fluid connecting circuit for fluid connection between the supply inlet and either the actuating inlet or the non-actuating inlet, the fluid connecting circuit comprising a control element movable between: • a first control position wherein the supply inlet is in fluid connection with the actuating inlet, and • a second control position in which the supply inlet is in fluid connection with the non-actuating inlet; • a first control position wherein the supply inlet is in fluid connection with the actuating inlet, and • a second control position in which the supply inlet is in fluid connection with the non-actuating inlet; wherein the control element is configured to be moved from the first control position to the second control position when the centrifugal force generated by the rotation of the boring bar about the rotation axis reaches a centrifugal force threshold, the control element being configured to be moved from the second control position to the first control position when the centrifugal force generated by the rotation of the boring bar about the rotation axis is below the centrifugal force threshold, wherein the boring bar comprises at least two receiving portions to receive a plurality of cutting insert cartridges distributed on the boring bar about the rotation axis, characterised in that a lubrication orifice is formed in each receiving portion, the non-actuating inlet is in fluid connection with each lubrication orifice to discharge the fluid on a cutting insert mounted on each cutting insert cartridge received in the receiving portions, wherein the non-actuating inlet comprises a circular groove, the actuating device further comprising a plurality of lubrication channels, each lubrication channel extending from the circular groove to a lubrication orifice formed in a receiving portion.