Abstract: One end of a collapsible cylinder having an impermeable side wall is shaped to form an impermeable shoulder and neck liner on which a polyethylene head can be molded. The end of the collapsible cylinder is crimped by a plurality of arms which are swung down simultaneously to form the end of the cylinder into a plurality of pleats, each pleat having a shoulder portion and a neck portion. Each arm carries a prism like member which creases and partially folds over the pleats. This crimped cylinder is then removed to another location where a shoulder forming block descends axially on it to form the shoulder including a re-entrant edge at the outer periphery of the shoulder. A series of truncated, pie-shaped blocks are brought in radially to contact the pleats and complete the folding over of the pleats. The intermediate product thus formed is ready to have the plastic head molded onto it.