Re: Safety undercuts

Mike --

The other day I had my SCT out at a public event. A boy came up and wanted to take a look, but the eyepiece was a little too high. So I angled it to the left for him. At which point the weight of the eyepiece caused the barrel of my WO diagonal to unscrew until the eyepiece was pointing directly down.

Now, I don't know if the eyepiece would have fallen out without a safety undercut, but my dislike of them was somewhat tempered by this event.

I now always angle the diagonal clockwise (so the weight tries to screw the barrel in farther). I've also noted that with a little wear on the compression ring, the undercuts seem to catch less often. You might even want to sand or file the corners of your brass (or copper) compression rings a bit. It's too bad the manufacturers don't make them a bit rounded.

-- Jeff.

Most Dob Newts, including mine, cannot dump an eyepiece, so the device has little or even negative safety value there. I just accept it as one of those little inconveniences in life that exist entirely for the benefit of other people.
--
Mike

I would actually like to see them make the safety groove angled like the WO diagonal insert is - so that the setscrew pulls the eyepiece in. I had a diagonal with a normal safety undercut, and it was a real pain because when I got a new scope, the edge of the groove was right where the setscrew was, and it wouldn't sit flush. So I replaced it with a WO diagonal, and the reverse-cone shape of the barrel means that no matter where the setscrew hits on it, it pulls the diagonal in securely. And since it is an angle, loosening the setscrew lets is slide out smoothly without catching. I think that would be great on eyepieces, and would work equally well with setscrews or retaining rings.

Jarad