An industrial borescope is a device used to inspect the insides of machine bores and passages, usually for maintenance and product quality control. The scopes have a handle and viewer at one end with a protruding optical tube that may be either rigid or flexible, and that easily inserts into bores.

The optical tube usually consists of two relays: one relay for the image and a second as a light source. At the insertion end of the optical tube is a lens. Industrial borescope manufacturers typically produce borescopes with one of the following four lens types:

1. Achromatic doublet, for bores of at least 5mm in diameter (no maximum).

2. Fused quartz fibers, for ultra-tiny bores and suitable for medical endoscopes.

3. Gradient index-reliable, which makes for a high quality image in small- to medium-sized bores.

4. Rod lens industrial borescopes, which produce a bright image.

Action Steps
The best contacts and resources to help you get it done

Locate quality, functional industrial borescopes for sale

First off, look for a borescope that works for your bore sizes. The main factor that determines the minimum size bore a scope will work for is the diameter of the optical tube. Also, how deep are your bores? Get a scope with enough working length. Lastly, how accessible are the bores you want to inspect, and are there any special shapes or parameters? Should you be thinking rigid, or is flexible worth the extra costs?

I recommend: Among industrial borescope distributors, FRS Omega, Inc. is a good place to start looking. Besides basic rigid models, they have several types of flexible scopes, including articulating models that have outside diameters as small as 2.5mm. They also have non-articulation models with ODs well under 1mm. Lenox Instrument Company is another good source for all sorts of borescopes.

Find industrial borescope suppliers that carry borescopes with the right tip type for you

Tip type can be a little tricky. The field of view (FOV) is the size of the area imaged, usually between 50 and 100 degrees. Direction of view (DOV) can be straight on down the bore, or 90 degrees, which is called direct viewing. Forward oblique is a somewhat angled view between straight on and to the side, or 0 to 90 degrees. This is a good compromise between insertion navigation ease and detailed inspection. Retro DOV is backward or even adjustable. If they are published, pay attention to focus distances as well.

I recommend: Gradient Lens Corporation clearly publishes FOV and DOV, as well as the other basic specifications for their products. Also check out Fiberscope.net, which has many varieties of borescopes, including both portable and heavy duty industrial video borescopes.

Search out an industrial borescope or industrial endoscope for rent

High quality borescopes and endoscopes are not cheap. If you don't regularly need this type of inspection equipment, renting is a viable option. A drawback is that your product selection will be considerably smaller.

I recommend: Electro Rent Corporation and Atlas Inspection Technologies are two good sources for borescope rentals. Between the two of them, you should have a decent chance of finding a borescope that will work for you. As for medical endoscopes, Medical Recovery Company, Inc. sells new and used scopes and also rents and repairs scopes.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Lens types do make a big difference, but overall design and quality is important as well. Don't base your choice of industrial borescopes solely on technology types.