Thread: USB Borescope - now as good as a Hawkeye ?

USB camera endoscopes are now common enough for around $20 online with the 5.5mm diameter required for fitting most bore sizes. The problem remains the relatively long focal length settings on these, often around 4cm. For this reason I’ve again sat on my wings on this one and not purchased any until now, maybe checking once every 6 months or so to see if anything more suitable would turned up. When I came across one that advertising a 1.5cm focal length and 60° viewing angle I thought that it sounded a bit more promising.

https://www.aliexpress.com/snapshot/...Id=32905146083

All the details are there. If you can’t be bothered then here are some pics.



The lens must be smaller than the 0.21” detector size because there is room for six LEDs around the outside. Android or PC compatible. I used NCH Software’s Debut video capture. Connector options and the LED brightness control shown below. As supplied the cable end diameter allows the entire endoscope to be fed into a 7mm barrel, otherwise for smaller bores the view is limited to reaching in 130mm from each end.



I measured the usable focal length: 12-16mm would be my assessment.

Here are some pictures. First up Ackley’s 40° shoulder approaches. Not really that interesting.



Here is some fire cracking in a True-Flite barrel chambered in 280AI after 1200 rounds. I set the LED intensity to highlight the lands. Also visible is some copper smearing in places.



Only the portion indicated is well focused within the distance range previously given.

The problem remains that looking at rifling axially, at an acute angle, and focused some distance away - even if this is only 14mm - is simple not as good as if viewed at right angles close up to the surface as with a Hawkeye.

Some of these endoscopes are supplied with right angle mirror accessories, but not this one (only some plastic ear pickers). It may be possible to get versions with a mirror. The diameter of the plastic sleeve of any adapter would need to be checked to see what limitations it places on calibre fit. So this time around it had to be a DIY add-on.

First up I needed a source of mirror on a plastic substrate so it could easily be shaped to size. What is required is a tiny elliptical mirror, 5.5-6mm across and 1.4 times this in length so it looks like a circle when tipped back at 45°. This could be made a bit bigger if only large calibre barrels were to be inspected. I had some spare reflectors leftover from Mini Maglite LED upgrades. Although the surface was a little concave this didn’t seem to impact the end result much. With plastic the mirror is a surface finish and easily scratched. I covered the surface with Sellotape while the piece was being shaped – in the same way that many plastics have protective sheets applied.



If you can find a tight fitting (5.5mm) black soda straw to mount the mirror then use that otherwise one can be easily made from paper. I blackened one end to reduce flaring from the LEDs.



The paper was tightly rolled onto the endoscope tube and layered with Sellotape over the top. It needs to be able to slide while still being a snug fit.



A viewing slot in cut at the end as shown. The mirror is first mounted with superglue.



The angle can be set up by looking at the video of the mirror as seen through the camera, or checking that the light from the LEDs reflects at right angles as shown above. The glue should be applied sparingly with a pin end. Getting glue on the mirror surface is fatal, and probably the same can be said of the endoscope.



I made the bond a bit more secure by back-filling with 5-minute epoxy, arrowed in the above. The protective tape is removed from the surface as a last step.



Focusing is now achieved by sliding the lens tube along the endoscope for a combined path length of 14mm between the surface to be inspected and the lens. The Borescope is then good to go.



Here is a bit of a gallery to help form opinions on the original title question. I have to say I did appreciate the large screen view and not having to squint into an eyepiece.


Below is the same 280AI as previously, showing the neck-to-freebore transition.



This next one is 75mm up from the chamber showing fire cracking on the top surface of the lands.



This is the groove surface about 100mm up from the chamber.



A different barrel this time, a Bartlein 5R chambered in 6.5x47. This shows some slight chambering marks in the freebore still there after 1500 rounds.



Below, slight deterioration in the leade. Maybe time to set it back in another 500 ?



100mm further up the barrel and it still appears mint. That is the edge of one of the 5R lands mid-image.



The Bartlein 5R rifling profile at the muzzle...



...and just down inside the muzzle end showing some light fouling on the edges of the lands. Easy to pick this up - copper and carbon - a perfect tool for getting that cleaning regime fine-tuned.



This last one is a Krieger 5R blank in .284" - silky smooth, and a nice clean edge on the lands right there.