Threaded Hole Inspection Borescopes

Threaded holes are holes with internal screw threads, enabling secure fastening with bolts or screws. Visual inspection is one of the critical methods to ensure the quality of threaded holes. Normally the visual inspection of a threaded hole is assisted with a microscope or a borescope. 

One example of inspect a M2 threaded hole with NP-0-1411 video borescope below.