What Are Borescopes?

A borescope is a small diameter optical instrument for viewing inside of things. It is the technical equivalent of a medical endoscope which is used for viewing inside the human body. Borescopes are made to go through very small holes or openings, allowing the user to look inside of objects without disassembly or destructive testing, giving a wide angle view of the interior. They range in diameter from about 0.5 mm up to 12 mm, and the lengths vary from a few inches to several feet. Typical uses include looking inside engines, castings, rifle barrels, machined metal parts, fuel injectors, hydraulic sleeves, valves and manifolds, behind walls, in heat exchangers, ductwork, etc.