Abstract: The tool comprises a head (1) for gripping the cluster (2), connected to a handling member (3) slidable in a tool body (4) between an active position in which the head (1) and at least part of the member (3) project from the body (4), and a retracted position in which the head (1), the handling member (3) and at least part of the cluster (2) extend within the body, and combs (5 to 10) for guiding the rods, at an end of the body (4) and displaceable between a retracted position in which they extend along the body (4), and an active position in which they extend perpendicularly to the body, in order to guide the rods. The tool also comprises springs (13) for stressing the combs into the active position and a sleeve (15) for retracting the combs, displaceable between retraction and release positions of the combs, by the head (1) and/or the handling member (3) during their displacement between their active and retracted positions within the body (4).