Forming a sector for a nacelle lip skin from a sheet metal blank via punch by placing the blank against an outer surface of the punch and clamping a trailing edge of the blank in a clamping member that grips a trailing edge of the blank without slippage; gripping a leading edge of the blank, opposite the trailing edge, in a gripping device at a location axially spaced from the punch with sufficient force to permit the blank to flow therethrough in a controlled manner; displacing the gripping device in a first direction, radially with respect to the punch while drawing the blank through the gripper; displacing the gripping device in a second direction, axially with respect to the punch, to draw the blank over the leading edge of the punch and through the gripping device.