1. IN A METHOD OF BINDING AND TRIMMING COVER MATERIAL ON TUBULAR MATERIAL, ALL MATERIAL HAVING THERMOPLASTIC SURFACE CHARACTERISTICS, THE STEPS COMPRISING, BENDING THE OPPOSITE OUTER ENDLESS EDGES OF SAID TUBULAR MATERIAL, SUPERPOSING ON EACH ENDLESS EDGE A COVER, WHEREBY THERE WILL BE TWO MULTIPLE LAYERS SPACED FROM EACH OTHER, EACH LAYER BEING DISPOSED NEAR AN END OF SAID TUBULAR MATERIAL, SUBJECTING BOTH OF SAID SPACED MULTIPLE LAYERS SIMULTANEOUSLY TO THE SAME PRESSURE AND TO HEAT FOR BINDING THE SAME, AND EXERTING PRESSURE OF THE SAME MAGNITUDE TO BOTH LAYERS FOR CUTTING SIMULTANEOUSLY INTO THE LAMINATIONS FORMED BY SAID LAYERS TO A PREDETERMINED FRACTIONAL LAYER DEPTH.