Which procedure is essential for accurate hole measurement?

The importance of inspecting the hole at multiple locations stems from the need to ensure accuracy and consistency in measurements. During the drilling process, variations can occur due to numerous factors, such as drill bit wear, material deformation, or misalignment. By measuring at different points around the hole, you can identify any discrepancies that may exist due to these factors.

This multi-point inspection approach helps in confirming the hole's diameter is uniform and meets the required specifications. It can also prevent issues that might arise from a single measurement that does not represent the overall condition of the hole. When you measure only once, or do not check after the first drill, you may overlook significant variations, leading to potential fitment or structural issues in the assembly process. Thus, this method of thorough inspection is crucial for achieving accurate hole measurements that are integral to safety and performance in aerospace applications.