A heated aluminium log which is to be sheared is inserted through a stationary die 11 and a movable die 12. A clamp (25) of the stationary die is then moved towards an axis of that die to clamp the log against a diametrically opposite portion of the internal surface of the die. Opposite members (15,16) of the stationary die are then moved towards each other in a direction perpendicular to the direction of movement of the clamp, to limit expansion of the sheared log.