Abstract: An extrusion die is disclosed for producing a compound extrusion in the form of a lined tubing where the materials forming the main tubing wall and the lining are difficult to bond. The die includes a plenum chamber in which there is spider-mounted a torpedo section passed which the main extrudate flows. The torpedo section is equipped with the circumferential orifice for orthogonally injecting the secondary extrudate as an internal lining. The combined extrudate is then caused to flow through a conical passageway which increasingly confines the combined extrudate and enhances the bonding therebetween. Thereafter, the combined extrudate passes through a passgeway having a constant clearance dimension wherein the bonded materials are stablized before they are permitted to exit the die.