A keyway, a small drill point and a car-door cavity put three different limits on a locksmith's inspection probe. Measure the opening and the route to the target, then decide whether a direct optical view or a saved image is needed. The Super Thin Micro Borescope starts at 0.04 in (1.0 mm) for a narrow route; the Ultra Fine Micro Borescope offers 0.37 mm and 0.5 mm versions for finer access; a Videoscope VOYAGER M40 can turn its tip when the route admits at least a 0.08 in (2.0 mm) probe. Fiberscope sells these tools and services them in-house.
Measure the smallest restriction, not the face of the lock
A 0.04 in (1.0 mm) probe only passes when every shoulder and bend along its working route clears that outside diameter. The face opening alone cannot establish that fit. Mark the entry width, route length, internal turns, and the direction from which the target must be seen. In a car-door cavity, the access point may be generous but the latch or reinforcement can block a straight view. In a safe-tech inspection through a drilled opening, note the distance from the opening to the target before choosing working length.
| Route | Instrument to consider | Trade-off |
|---|---|---|
| Very narrow opening and mostly straight path | Ultra Fine Micro Borescope, 0.37 or 0.5 mm version | Optical view requires external illumination; no tip steering |
| Narrow route with flexible shaft | Super Thin Micro Borescope, from 0.04 in (1.0 mm) | Eyepiece viewing; capture needs a separate camera |
| Larger car-door or service opening with a turn | Videoscope VOYAGER M40, from 0.08 in (2.0 mm) | Integrated display and steerable tip, but larger minimum OD |
A named lock is not an access dimension. The rigid and optical borescope guide explains how fixed optics differ from coherent fiber-bundle scopes. For wider industrial access where image evidence is primary, see the industrial videoscope comparison.
Super Thin Micro Borescope for a narrow flexible path
The Super Thin Micro Borescope starts at 0.04 in (1.0 mm) OD and can be ordered with up to 4.9 ft (1.5 m) working length. It uses a coherent fiber image bundle and a 45° field of view. Choose a flexible or semi-rigid insertion version to suit the route. The probe sheath can be submerged, while the eyepiece and light connection remain above the work area.
From $1,750 to $3,100 across configurations, prices checked September 26. This is the practical optical pick where a 1.0 mm opening leads to a route that can be guided to the target. The eyepiece needs a compatible light source. To record, add an optical camera matched to its eyepiece; the scope itself is not a USB probe.
Ultra Fine Micro Borescope for smaller access
The Ultra Fine Micro Borescope offers 0.37, 0.5 and 0.75 mm optical probes; the 0.5 mm version has a 25 mm minimum bend radius. The coherent quartz-fiber bundles carry 3,000 fibers at 0.37 and 0.5 mm, and 10,000 fibers at 0.75 mm. Image detail improves with the larger bundle, so choose the widest probe that clears the full route.
From $3,520 to $3,930 across configurations. Use it for an exceptionally small existing inspection opening in a lock assembly or precision mechanism where a flexible optical view helps. The set includes the scope; illumination comes from a separate compatible source. This scope is not an articulated videoscope and needs an added camera to save images.
Videoscope VOYAGER M40 for tip control and evidence
The Videoscope VOYAGER M40 uses 360° joystick articulation, a 5-inch screen and probe ODs from 0.08 to 0.24 in (2.0–6.0 mm). A locksmith working through a larger car-door service opening can aim the lens at a latch or misplaced part and capture an image in the host. Choose a probe length against the measured route and a diameter against its narrowest restriction.
From $4,160 to $8,240 across configurations. The M40 wins when viewing direction and a saved file matter more than sub-millimeter access. A 0.08 in (2.0 mm) probe will not enter an opening sized for the 0.5 mm Ultra Fine option. Watch the VOYAGER M40 in use.
What you'll also need
Optical scopes need light at the tip and a separate capture path when the job requires photographs. A compatible light source and cable illuminate the Ultra Fine Micro Borescope. An optical camera and correct eyepiece interface let either optical scope feed a computer; the USB borescope camera guide distinguishes such camera modules from complete scopes. Preserve the original image alongside a note of the entry point and viewing direction.
FAQ
Can a micro borescope fit a keyway?
Only if the probe clears the keyway and all restrictions beyond it. The Super Thin Micro Borescope starts at 0.04 in (1.0 mm); measure the actual route.
Does the Ultra Fine Micro Borescope have video recording?
The Ultra Fine is an optical fiberscope. It needs a separate compatible camera and illumination setup to record a file.
When is VOYAGER M40 better than an optical micro scope?
Choose VOYAGER M40 when a 0.08 in (2.0 mm) or larger opening admits its probe and joystick tip movement helps see a target to one side.
Does a flexible shaft steer its tip like an articulating videoscope?
No. A flexible shaft follows the route as it is guided; the VOYAGER M40 has joystick-controlled tip articulation.
About the author
Vladimir Khubiryants, Founder & President, Fiberscope (MEDIT Inc.). Vladimir Khubiryants founded Fiberscope to give professionals access to reliable video inspection equipment without enterprise pricing. For over 20 years he has sourced and tested borescopes, sewer cameras and fiberscopes in Fiberscope's in-house test and repair facility, helping plumbers, pipeline engineers, aviation and military teams choose the right tool for the job.
Send the entry opening, narrowest internal clearance, straight or turning route, insertion length, viewing direction and recording requirement through the contact page or call 1-877-613-2210.
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