A stent graft delivery system comprising: a tip assembly having a tip tube (112; 312); a middle member tube (120; 320; 450) having a middle member proximal end and defining a middle member lumen, the tip tube being disposed in and longitudinally slideable within the middle member lumen; a sheath assembly having a sheath tube (132; 332) and a sheath handle operably connected to a sheath tube proximal end, the sheath tube (132; 332) defining a sheath lumen, the middle member tube (120; 320; 450) being disposed in and longitudinally slideable within the sheath lumen; a threaded assembly having an exterior thread (142; 202; 342), and defining a threaded assembly lumen, a first sidewall port, and a second sidewall port; and a unitary endoseal (150; 400) having an longitudinal cylindrical endoseal body and a transverse cylindrical endoseal body transverse to the longitudinal cylindrical endoseal body, the longitudinal endoseal cylindrical body defining an endoseal lumen having a proximal portion, a middle portion, and a distal portion, the transverse cylindrical endoseal body having a first cylindrical portion and a second cylindrical portion; wherein the tip tube is disposed in and longitudinally slideable within the proximal portion of the endoseal lumen, the middle member proximal end of the middle member tube (120; 450) is disposed in the distal portion of the endoseal lumen and fixed to the longitudinal cylindrical endoseal body, the first cylindrical portion of the transverse cylindrical endoseal body is disposed in the first sidewall port of the threaded assembly, the second cylindrical portion of the transverse cylindrical endoseal body is disposed in the second sidewall port of the threaded assembly, and the longitudinal endoseal cylindrical body is disposed in the threaded assembly lumen; and the sheath handle engages the exterior thread of the threaded assembly in a first configuration to move the sheath tube (132; 332) longitudinally relative to the middle member tube (120; 320; 450) and tip tube (112; 312) by rotation of the sheath handle and disengages the exterior thread of the threaded assembly in a second configuration to move the sheath tube (132; 332) longitudinally relative to the middle member tube (120; 320; 450) and tip tube by longitudinal motion of the sheath handle. a tip assembly having a tip tube (112; 312); a middle member tube (120; 320; 450) having a middle member proximal end and defining a middle member lumen, the tip tube being disposed in and longitudinally slideable within the middle member lumen; a sheath assembly having a sheath tube (132; 332) and a sheath handle operably connected to a sheath tube proximal end, the sheath tube (132; 332) defining a sheath lumen, the middle member tube (120; 320; 450) being disposed in and longitudinally slideable within the sheath lumen; a threaded assembly having an exterior thread (142; 202; 342), and defining a threaded assembly lumen, a first sidewall port, and a second sidewall port; and a unitary endoseal (150; 400) having an longitudinal cylindrical endoseal body and a transverse cylindrical endoseal body transverse to the longitudinal cylindrical endoseal body, the longitudinal endoseal cylindrical body defining an endoseal lumen having a proximal portion, a middle portion, and a distal portion, the transverse cylindrical endoseal body having a first cylindrical portion and a second cylindrical portion; wherein the tip tube is disposed in and longitudinally slideable within the proximal portion of the endoseal lumen, the middle member proximal end of the middle member tube (120; 450) is disposed in the distal portion of the endoseal lumen and fixed to the longitudinal cylindrical endoseal body, the first cylindrical portion of the transverse cylindrical endoseal body is disposed in the first sidewall port of the threaded assembly, the second cylindrical portion of the transverse cylindrical endoseal body is disposed in the second sidewall port of the threaded assembly, and the longitudinal endoseal cylindrical body is disposed in the threaded assembly lumen; and the sheath handle engages the exterior thread of the threaded assembly in a first configuration to move the sheath tube (132; 332) longitudinally relative to the middle member tube (120; 320; 450) and tip tube (112; 312) by rotation of the sheath handle and disengages the exterior thread of the threaded assembly in a second configuration to move the sheath tube (132; 332) longitudinally relative to the middle member tube (120; 320; 450) and tip tube by longitudinal motion of the sheath handle.