Fastener gap inspection is performed with which item?

Fastener gap inspection is primarily conducted using shim stock, which is a thin piece of material used to measure and gauge the space or gap between fasteners. Shim stock is particularly useful because it comes in various thicknesses, allowing mechanics to quickly and accurately determine whether the gap is within specification limits. By inserting the shim stock in the gap, the mechanic can assess whether it meets the required standards for proper fit and alignment.

In contrast, while feeler gauges are often used to measure gaps, they are more suitable for measuring very small distances that are precise and typically used in situations like measuring clearance or spacing between moving parts. Calipers and rulers are primarily used for general measurements and would not provide the necessary precision or are not designed specifically for gap measurements in the context of fasteners. As such, shim stock is the most pertinent tool for this specific inspection process.