[Walt Fricke]

10 or so years ago the Snap-on 5500 or something like that, at 7-800 dollars, was maybe the choice for shops for a bore scope. Then Harbor Freight came out with one for under $100 (no real ability to save pictures), and under $200 for a better model.

Nowadays, Snap-on has what looks like a better package - the scope probe attaches to a box, and the box attaches to the display so you don't have to stick your head way into the engine bay to see the display. Their 6600 or whatnot is still priced up there. Harbor freight about the same, and they still have the probe attached to a sort of gun with the display.

But for under $30 you can get just the probe, a small intermediate piece, and as much USB or other cable as you might want to use a huge computer monitor, a laptop screen, a tablet, or a smart phone (some, anyway) as your viewer. Those I have consulted on this agree that these are, indeed, a better mousetrap for shop use - bigger, clearer pictures, video if you want, and you can keep lots of scope pictures if you want easily. Don't even have to pull out an SD card for transfers. There may even be one which connects with Bluetooth, though that removes the value of the computer like device as the power source.

If you look at what Amazon has to offer under borescopes you will finds lots listed. Frustratingly, the sellers don't list a consistent set of specifications.

The Snap-on version has a screen resolution (if that's the right term) of 640x480. No self respecting user of a computer would want that low a screen resolution. I'm typing on a screen which is 1680x1050, and the 19" second monitor beside it is 1280x1024. I'm guessing that the typical laptop has a somewhat smaller set of numbers, but not down in the 640 range. I associate that, probably wrongly, with DOS and the early 1990s.

What I am looking for includes how good the camera part is (I thought these were fiberoptic, but I was way wrong - these use a miniature video camera) its camera pixel count. Many say they are 2 megapixels. That seems plenty large for a bore scope for automotive purposes (mine include checking inside engines for parts not allowed for class racing, which may be more subtle than finding foreign objects or looking for scored cylinders). But, naturally, not all models list the megapixel ability.

Just what resolution (if that is the right word) is as high as will do any good on, say, a 15" screen? I assume that a resolution needed for a huge wall mounted TV screen or the like is overkill for a smaller screen. Though having pictures with more pixels in them means parts can be blown up more than those with fewer. How does the camera pixel count relate to being able to match the native resolution of lap top screens?

It appears that the standard camera is 5.5mm in diameter, and is surrounded by six LEDs. Some are white, some tout blue a being better. The total width of the head is thus wider, but won't all of these fit within a 12mm spark plug hole?

Then there is focal length - at least in the sense of how close to something can the camera get and still get a good picture? One which otherwise seemed likely (and I ordered one just to see, as they are so relatively cheap) listed this as 3-6cm. 3cm is about 1.2" 6cm is 2.4". Both seem perhaps a bit limiting. Others tout a half inch near limit, which seems OK. Many don't mention this.

Another spec is angle of view, which seems to run from about 55 degrees to 66 degrees. Are these differences enough to worry about?

3' (or one meter) seems about as short as any of these are for the probe length (all are flexible, but generally stiff enough to hold a shape I think), but some only come in 3 meter or longer lengths. Longer is good for looking inside plumbing in or outside a house, and probably doesn't really matter for automotive purposes, but maybe it does?

What else matters? Do any of these come with software which is so poor as to be a problem once you plug the USB end in?

Anyone have a favorite they have used which I should consider for my purposes? There are several lists out there in Google land which purport to compare bore scopes or endoscopes (not the medical variety). Most of those are the kind with the little self contained screen, some of the sort of pistol configuration Harbor Freight carries. I don't care about any of those, just the kind you plug into a screen on a separate device.