advantageously prevents the unwanted movement of the clamps 60 relative to the baseplate 62 and defines a plurality of mounting locations of the clamps 60 relative to the baseplate 62 to achieve fine adjustment of the clamps 60 relative to baseplate 62 turning now to fig6 the clamps 60 are installed by sliding the hook portion 72 along direction 86 until an end or corner 96 of the flange 70 is disposed in a generally circular relief section 94 as will be explained in greater detail below the hook portion 72 also includes a top abutment surface 90 and a bottom abutment surface 92 on either side of the relief section 94 that engage opposing sides of the flange 70 still referring to fig6 the relief section 94 has a radius and is tangent with the bottom abutment surface 92 however the top abutment surface 90 is not tangent with the relief section 94 such a configuration advantageously ensures that the top abutment surface 92 exerts a pressure against an upper surface of the flange portion 70 interior from the end or corner 96 of the flange section 70 of each rail such a configuration avoids the undesirable effect of deformation of the corner 96 of each flange portion 70 this arrangement is further illustrated at fig7 turning now to fig8 another embodiment of a temporary fastener 150 is illustrated this embodiment is generally similar to that described above relative to fig3 7 with the exception that clamp 160 of this embodiment of a temporary fastener 150 includes a plurality of serrations or abutments 164 formed on an underside of the clamps 160 the abutments 164 are used to finely adjust the positioning of the clamps 160 relative to.