What function does the gap inspection shim serve in the riveting process?

The gap inspection shim plays a vital role in ensuring that the rivets are properly installed during the riveting process, particularly concerning the flushness of the rivet heads. When rivets are installed, achieving the correct flushness is essential for both aerodynamic performance and structural integrity. The shim is used to assess the height of the rivet head relative to the surface of the materials being joined.

By inserting the shim into the gap between the rivet head and the surface, a mechanic can visually and physically verify that the rivet is seated appropriately, ensuring a smooth and even surface. If the rivet head is not flush, it can lead to potential issues such as drag on the aircraft, failure under stress, or even damage during operation. This inspection is critical for quality control in aerospace assemblies where even small deviations can have significant consequences.

While there are other important aspects of inspections in the riveting process, such as aligning rivet shafts, inspecting height and diameter, and confirming rivet type, the specific function of the gap inspection shim is focused on evaluating the flushness of rivet heads to maintain the required standards in aerospace construction.