I had that problem when I first got mine (brand new).

In my case, the tripod adapter was simply threaded poorly. In your case,
the threads may have been damaged, or the tripod bolt may have bad
threads.

In the first two cases, one option is to rethread the adapter. If the
bolt is bad, you'll want to replace it.

The adapter is held in by three small hex-head screws on the base. You'll
know which ones as soon as you look a the bottom.

Take the adapter out, and remove the tripod bolt from the tripod (it will
requite removing a small clip, which you shouldn't lose). Put some kind
of lubrication on the bolt (white lithium grease would probably be best,
but I used what I had on hand, which was WD40), and screw it into the
adapter *backwards*. That is, start from the part of the adapter that's
internal to the scope.

As long as you're sure you started it straight, force it all the way
through. It should now screw in easily in either direction.

Mike,

I was looking at it and thought about doing just what you suggest. Of
course if worst comes to worst I suppose I could get both the adapter
and bolt replaced.

Jay