Method and machine for machining parts in bar form with automatic part reversing and recalibration system

An automatic method for changing a machining reference frame on a machine for machining a part from a bar, the bar being held during machining by at least two distinct and independent clamping devices, each having a longitudinal movement along, and a rotation about, an axis parallel to a long axis of the bar, allowing for a relative angular and longitudinal displacement of one of said at least two clamping devices relative to an other of said at least two clamping devices, wherein, in order to proceed with a change of reference frame,

• the one of said at least two clamping devices releases the bar and disengages therefrom to turn freely about the long axis of the bar independently of the other of said at least two clamping devices, then aligns angularly into a different clamping reference frame of the bar before retaking the bar, and
• the other of said at least two clamping devices, after the one of said at least two clamping devices retakes the bar, releases the bar and disengages therefrom to turn freely about the long axis of the bar independently of the one of said at least two clamping devices, then aligns angularly into the different clamping reference frame of the bar before retaking the bar.