Geoff Frost

So this is my solution to get the finder scope to focus. The result works perfectly. I now have plenty of focus adjustment after focussing the crosshairs. I removed about 5 or 6mm from the tube length and the joined it back together again.

Not sure if this will work but I will upload the drawings for comment.existing.pdf spacer.pdf modified tube.pdf

So, just carried out some measurements and there is only 1mm max of spare thread which still makes the focusing tight. Plan B. Cut the tube and insert a spacer.

I am in the UK. I have exactly the same problem. I think the main tube is about 5 to 6mm too long. This would bring the main focus into some sort of mid position. Could skim about 1mm off eack end of the main tube. This would reduce the threads but they may still function. Do I give it a try???? Oh I have two tubes and two eyepieces. One set is slightly better than the other but both are screwed right down to the minimum.