A method of assembling a guide wire luer hub and a coaxial tubing having an outer cover surrounding an inner body with a guide wire lumen of diameter DGW, comprising: providing a guide wire luer hub, the guide wire luer hub comprising: a hub body having a longitudinal axis; and a hub lumen extending through the body, the hub lumen having: a centering lumen section having a diameter DCL generally equal to or lesser than the diameter DGW; a proximal lumen section having a distal diameter generally equal to the diameter DCL; a radially wider distal lumen section and a radially narrower distal lumen section, the radially wider distal lumen section being distal of the radially narrower distal lumen section; and a stop at a junction between the radially wider and radially narrower distal lumen sections, the stop adapted to abut with at least a portion of the outer cover and allow at least a portion of the inner body to extend into the radially narrower distal lumen section with the guide wire lumen longitudinally aligned with the centering lumen section, and characterised by: preparing the coaxial tubing by removing a portion of the outer cover to provide an exposed proximal portion of the inner body; applying adhesive to a proximal end face of the outer cover and a radial surface (20P, 20P', 20P") of the exposed proximal portion of the inner body; and inserting the exposed proximal portion of the inner body into the narrower distal lumen sections until the proximal end face of the outer cover abuts with the stop junction. providing a guide wire luer hub, the guide wire luer hub comprising: a hub body having a longitudinal axis; and a hub lumen extending through the body, the hub lumen having: a centering lumen section having a diameter DCL generally equal to or lesser than the diameter DGW; a proximal lumen section having a distal diameter generally equal to the diameter DCL; a radially wider distal lumen section and a radially narrower distal lumen section, the radially wider distal lumen section being distal of the radially narrower distal lumen section; and a stop at a junction between the radially wider and radially narrower distal lumen sections, the stop adapted to abut with at least a portion of the outer cover and allow at least a portion of the inner body to extend into the radially narrower distal lumen section with the guide wire lumen longitudinally aligned with the centering lumen section, and a hub body having a longitudinal axis; and a hub lumen extending through the body, the hub lumen having: a centering lumen section having a diameter DCL generally equal to or lesser than the diameter DGW; a proximal lumen section having a distal diameter generally equal to the diameter DCL; a radially wider distal lumen section and a radially narrower distal lumen section, the radially wider distal lumen section being distal of the radially narrower distal lumen section; and a stop at a junction between the radially wider and radially narrower distal lumen sections, the stop adapted to abut with at least a portion of the outer cover and allow at least a portion of the inner body to extend into the radially narrower distal lumen section with the guide wire lumen longitudinally aligned with the centering lumen section, and a centering lumen section having a diameter DCL generally equal to or lesser than the diameter DGW; a proximal lumen section having a distal diameter generally equal to the diameter DCL; a radially wider distal lumen section and a radially narrower distal lumen section, the radially wider distal lumen section being distal of the radially narrower distal lumen section; and a stop at a junction between the radially wider and radially narrower distal lumen sections, the stop adapted to abut with at least a portion of the outer cover and allow at least a portion of the inner body to extend into the radially narrower distal lumen section with the guide wire lumen longitudinally aligned with the centering lumen section, and characterised by: preparing the coaxial tubing by removing a portion of the outer cover to provide an exposed proximal portion of the inner body; applying adhesive to a proximal end face of the outer cover and a radial surface (20P, 20P', 20P") of the exposed proximal portion of the inner body; and inserting the exposed proximal portion of the inner body into the narrower distal lumen sections until the proximal end face of the outer cover abuts with the stop junction. preparing the coaxial tubing by removing a portion of the outer cover to provide an exposed proximal portion of the inner body; applying adhesive to a proximal end face of the outer cover and a radial surface (20P, 20P', 20P") of the exposed proximal portion of the inner body; and inserting the exposed proximal portion of the inner body into the narrower distal lumen sections until the proximal end face of the outer cover abuts with the stop junction.