Abstract: In a method of forming a neck and flange at the open end of a thin cylindrical metal can body, the can body is held endwise under compression while an axial shortening force and a radial deforming force are applied to the can body sidewalls, by relative axial movement between the can body on the one hand and, on the other hand, an external forming tool and an internal tool edge which are kept at constant axial spacing from each other, so that the neck and flange are formed in free space without any need for internal or external tools shaped to the required profile; any desired shape can be obtained by varying the characteristics of the relative axial and radial motions.