In various representative aspects, an assembly for securing a support bracket to rail guide used for mounting and installing solar panels is provided. More specifically, the assembly provides a novel and improved nut with a serrated surface in combination with a t-bolt with a serrated surface that is capable of penetrating the respective oxidation surface layers of the bracket and the rail guide when installed. When installed, provides a mechanism for using the bracket to connect the rail guide to a flashing that is typically installed on a roof. An alternate embodiment of the nut also includes rotational and vertical stabilizing features that prevent the nut from moving along the bracket once it is secured. By employing the apparatus at various locations along the roof in a linear fashion, the rail support structure can be properly installed so that an array of solar panel modules to be installed.