With particular reference to FIGS. 19 and 34-37, the longitudinal connecting member assembly 101 is assembled by first placing the sections 104 and 105 in a jig or other holding mechanism such that the jig frictionally engages the rod portions 116 and 146 and holds the concave surface 122 of the section 104 in a position spaced from the convex surfaces 130 and 154 of the section 105 with the surfa