How to Find the Right Borescope Diameter on Hawkeye Borescopes

Hawkeye Borescopes organizes its catalog around insertion diameter, and that is the fastest way to narrow your options. Start with the smallest opening your scope must pass through, then use the site's Choose by Size filter to see only the models that fit. If your access hole is under 2 mm, you are limited to the MicroFlex Fiber (0.4–1.5 mm) and Micro Q2 (0.8–2 mm) families. If you have 4–6 mm of clearance, the X-PLOR HD, Motorized HD, and Q2 HD video borescopes become available, and those larger diameters generally bring higher-resolution imaging and more articulation options.

Start with the smallest hole in the inspection path

The binding constraint is almost never the main cavity — it is the tightest passage the scope must travel through. Measure or look up that minimum dimension first, then add a small clearance margin. A 2 mm scope will not pass a 1.9 mm port, and forcing it risks damaging both the scope and the hardware.

Hawkeye's size filter uses these bands:

The site also lists rigid scopes by diameter directly: Pro Hardy at 6.35 mm, Pro Slim and Pro Slim Prism at 4.20 mm, Pro SuperSlim at 2.40 mm, Pro MicroSlim at 1.85 mm, and Pro MicroFlex Semi-Rigid down to 0.9 mm.

Match the family to the job, not just the number

Diameter gets you into the hole; the scope type determines what you can actually see and how you steer.

• MicroFlex Fiber (0.4–1.5 mm) — the smallest option listed. Fiber optic imaging, best for extremely tight passages where nothing else fits. Expect lower image quality than video scopes.
• Micro Q2 (0.8–2 mm) — small-diameter video. A step up in image clarity while staying under 2 mm.
• Pro MicroSlim (1.85 mm) — rigid, so it needs a straight or nearly straight path.
• Pro SuperSlim (2.40 mm) — rigid, slightly larger, useful when the bore is straight and you want more light or field of view.
• Q2 HD and Q2 Dual View HD (2.8–6 mm) — flexible video with HD imaging; Dual View adds a second viewing direction.
• X-PLOR HD (3.9 and 6 mm) and Motorized HD (4 and 6 mm) — larger flexible video scopes with articulation, suited to aviation and industrial work where you need to steer around bends.
• Pro Hardy (6.35 mm) and Pro Slim / Pro Slim Prism (4.20 mm) — rigid scopes for straight bores such as gun barrels, tubes, and machined passages.

The general trade-off: smaller diameter means access to tighter spaces but less light, lower resolution, and often no articulation. Larger diameter means better images and more control, but it will not fit small ports.

Check insertion depth and rigidity before you commit

Diameter alone does not guarantee the scope reaches the inspection point.

1. Confirm the full path length. A flexible scope can follow bends; a rigid scope cannot. If the path is curved, a rigid 1.85 mm Pro MicroSlim will not work even though it fits the diameter.
2. Check working length. The product listings specify length; match it to the depth you need to reach, not just the entry diameter.
3. Account for articulation. If you need to look sideways or around a corner, you need an articulating video scope (V3 HD, Motorized HD, or Q2 Dual View HD) rather than a fixed-forward rigid or fiber scope.
4. Verify the tip can pass. Interchangeable tips and articulation mechanisms can effectively increase the diameter at the tip. Confirm the tip dimension, not just the shaft.

Use the site's own selection tools

Hawkeye provides two direct routes:

• Choose by Size — filters the catalog into the four diameter bands above.
• Product Search — search by model name or diameter if you already know your target.

For aviation and aerospace maintenance specifically, the site positions the V3 HD Video Borescope as the most popular choice, citing HD imaging, a touchscreen interface, servo joystick articulation, and interchangeable tips. That is a 4–6 mm class instrument, so it only applies if your access port is at least that large.

If you are unsure which diameter fits your application, Hawkeye offers a Request A Free Trial option and a phone line (800-536-0790) listed on the site. Note that the company lists a change of address effective January 1, 2026 to 4647 Jackson Lane, Phelan, CA 92371, with all other contact information unchanged.

Quick decision path

• Hole under 2 mm → MicroFlex Fiber or Micro Q2.
• Hole 2–4 mm, straight path → Pro SuperSlim (2.40 mm) or Pro MicroSlim (1.85 mm).
• Hole 2–4 mm, curved path → Q2 HD or Q2 Dual View HD.
• Hole 4–6 mm, need articulation and HD → X-PLOR HD, Motorized HD, or V3 HD.
• Straight bore, larger diameter → Pro Slim (4.20 mm) or Pro Hardy (6.35 mm).

Measure the tightest passage first, then filter by that number. Everything else — resolution, articulation, lighting — is a secondary choice you make within the diameter class that actually fits.