During fastener gap inspection, which of the following is a common tool used?

In fastener gap inspection, shim stock is commonly used as a tool because it allows for precise measurements of gaps between fasteners. Shim stock is typically a thin piece of material that can be inserted between components to measure clearances or to adjust the fit. This tool is particularly beneficial when the gap is too small to be measured directly with calipers or gauges, as it can provide a more accurate way to evaluate the spacing and alignment of fasteners.

Using shim stock can help in identifying whether a fastener is properly seated or if there is an unwanted gap that could affect the structural integrity of the assembly. By measuring the gap with shims of specific thicknesses, technicians can confirm that the fastener is installed correctly, ensuring that the assembly meets safety and operational requirements. This capability is critical in aerospace applications, where the accuracy of assembly is paramount to safety and performance.