A borescope is an optical device consisting of a rigid or flexible tube with an eyepiece on one end, a lens on the other, linked together by a optical system in between. Image:BorescopeApplication.png.jpg


The optical system is usually surrounded by optical fibers used for illumination of the remote object and a rigid or flexible protective outer sheath.


Scematic view of a rigid borescope.


Borescope in use with example of what you might see through the borescope.

Borescopes are used for inspection work where the area to be inspected is inaccessible by other means.

Different types[]

Rigid borescopes[]

Rigid borescopes are similar to a fiberscope, but are not flexible and generally much cheaper and provide a superior image.


Rigid borescopes are better suited to certain tasks such as inspecting automotive cylinders, fuel injectors, hydraulic manifold bodies and gunsmithing.


Rigid or flexible borescopes may be fitted with a magnification device and a way to illuminate the work being inspected. Usually illumination fibers are contained in the insertion tube of the borescope.

The eyepiece may be fitted with a coupler lens to allow the borescope to be used with imaging devices such as a video or camera.

When in use inside the human body, this device is referred to as an endoscope.

Uses by engineers[]

Borescopes are commonly used in the visual inspection of aircraft engines, aeroderivative industrial gas turbines, steam turbines, diesel engines and automotive/truck engines. Gas and steam turbines require particular attention because of safety and maintenance requirements. Borescope inspection of engines can be used to prevent unnecessary maintenance, which can become extremely costly for large turbines. They are also used in manufacturing of machined or cast parts to inspect critical interior surfaces for burrs, surface finish or complete through holes.

Other uses[]

Recently forensic applications in law enforcement and building inspection are also common uses for borescopes.

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