Altitude adjustment T-knob on NEQ6 stuck

[Alasdair]

I've recently acquired a second hand NEQ6 Pro mount, which (as I was shown at the time) is in very good working order. We took it apart to pack up for travel, and I'm only just now setting it up.

I put all the knobs in and took them out again, and now - the rear altitude adjustment T-knob simply won't go in. I've tried both knobs; both easily screw in at the front, but not at the back, so the problem (I'm assuming) is with the thread in the mount itself. Given that I've been very careful with it, I can't believe that I could have stripped a thread - I've done no forcing at any time. But at the rear, the thread on the knob connects with the thread in the mount; I can give it two turns, and that's it. It simply won't go any further.

It's not a matter of the mount being in a wrong position - as I said I put both adjustment knobs in earlier, then took them out. I just can't put them back in again. What might be going on here? And how can I fix it?

Just to be sure, a picture of the knobs I mean is at https://www.modernastronomy.com/wordpress/wp-content/uploads/2020/04/skywatcher_eq6_bolts-620x547@2x.jpg

Thank you in advance for any advice.

Alasdair

[JA]

Hi A,

Sorry to hear of your woes. The thread may be stripped, but more likely crossthreaded or perhaps obstructed in the thread grooves by some metallic debris. Carefully inspect the female thread and perhaps take a close up photo and post it here.

It may be possible to run a thread tap through the affected hole. Another possibility if the thread is really damaged is to drill out the thread and use a thread insert for repair.

If you want some help let me know.

Best
JA

[Alasdair]

Thanks so much, JA. I tried taking some photos, but they aren't very good; I'll try again tomorrow. (My only camera is on my Android phone.) It's very annoying though, although I suppose I could buy a thread tapper. I'll try first brushing it out to see if there's any debris caught in it. I'll have to see if I have a suitable wire brush first! Thanks again, Alasdair

[JA]

Try a straightened out paper clip with the very end , say the last 3mm bent at 90 degrees to serve as a hook type scraper for the thread grooves. Also look for any dent or deformation at the thread start.

Best
JA

[Alasdair]

In the end I took it out to Sidereal Trading (where I'd bought a case for it), and they tapped out the thread, as well as giving me a few pointers on how to manage it best without bending the bolts. All good now!


Thank you very much for your help and advice.


Alasdair