Abstract: Rigid packets of the type with a hinged lid are fashioned from diecut blanks presenting a central longitudinal portion flanked by two lateral portions, each consisting in a series of longitudinally disposed flaps. The method of manufacture involves directing the blanks singly and in succession between a pair of contrarotating rollers with dies shaped and positioned to engage each lateral portion; the dies are designed to modify a pair of adjoining flaps on each side, which ultimately will be bent through a right angle to form an internal layer of the relative flank face of the packet, by producing at least one bend in one flap at an end adjacent to the other flap, and forming a projection on the longer flap which in the finished packet will be breasted permanently in contact with an inner reinforcing frame.