A guide assembly comprises a frame assembly, a plurality of clamping assemblies, and a head assembly. The clamping assemblies may be mountable to the frame assembly for attaching the frame assembly to a structure. The head assembly may be mountable to the frame assembly and may include a tool coupled to the head assembly. The tool assembly may be axially movable relative to the head assembly to cause the tool to exert a down force on the structure when the frame assembly is attached thereto.