What tool is used to check the flushness of rivet heads?

The tool used to check the flushness of rivet heads is the gap inspection shim. This tool allows the technician to measure the gap between the rivet head and the surrounding surface of the material. When inspecting rivets, it is crucial to ensure that the heads are flush with the surface to maintain aerodynamic integrity and structural strength of the assembly. The gap inspection shim is specifically designed for this purpose, as it can fit into the space around the rivet head, making it easy to visually assess whether the rivet is seated properly and flush.

While calipers can be used to measure distances and dimensions, they are not specifically designed for assessing the flushness of rivets and may not provide the level of specificity needed for this type of inspection. Similarly, a rivet gauge is primarily used to measure the diameter and length of rivets but may not directly indicate flushness. A depth finder, on the other hand, is usually employed for measuring depths or recesses but does not play a role in determining the flushness of rivet heads. Therefore, the gap inspection shim is the appropriate tool for this task, emphasizing its significance in ensuring high-quality aerospace assembly work.