What procedure must be taken before drilling the bottom holes of the X-braces and knee braces when ground framing?

Trueing up pole tops is essential before drilling the bottom holes of X-braces and knee braces when ground framing because this process ensures that the poles are properly aligned and plumb. If the tops of the poles are not true, it may lead to misalignment in the installation of braces, which could compromise the structural integrity of the entire assembly.

By trueing the pole tops, you check and adjust the vertical alignment, ensuring that all components are installed correctly relative to each other. This step is crucial for maintaining the stability and safety of the structure, as it directly affects how forces are distributed across the frame.

Other procedures, such as lining up the braces or choosing drilling locations, are important but should occur after ensuring the pole tops are true. Installing safety equipment is always necessary in lineman practices, but it does not directly relate to the structural alignment of the braces and poles before drilling.