Help! Can’t screw adapter in far enough…

[mistuk]

trying to screw adapter into my straight thru finder so I can attach my ZWO camera. Bought the adapter from FLO - it’s definitely the right one, but can’t screw it in far enough to reach focus. 
 

I know it’s “user error”. Tried some dry PTFE spray on the threads but that hasn’t worked. 
 

any other thoughts?

 

Kev
 

 

[mistuk]

Ok. So this isn’t going well! I tried heating the end of the finder with a hairdryer to see if that would help. I’ve now threaded the adapter on - it went a little bit further, but nowhere near far enough…. And guess what - now it’s stuck!

Tips on how to loosen it (before it goes in the bin!)

looking at the two holes in the top of the thread I presume there’s some kind of tool to help - what would that be?

 

[PeterC65]

Yes those two holes are to help with removal, if you happen to have a suitable tool.

Are you sure that the adapter isn't screwed home? It's worth measuring the thread depth to check just how far it should screw in.

You say that you're not reaching focus. What finder are you using? I'd expect there to be enough focus adjustment on the finder to cope with quite a bit of variation in camera position.

When I have problems with threads I heat and cool the different parts and find that surprisingly effective. To separate the two I would heat the finder and adaptor with the hairdryer then dip the adapter end into iced cold water for a minute.

 

[Varavall]

17 minutes ago, mistuk said:

I presume there’s some kind of tool to help - what would that be?

One of these https://www.amazon.co.uk/Ocnvlia-10mm-130mm-Replacement-Spanner-Opening/dp/B0C7QG4LDF/ref=sr_1_3?crid=3AAJ9SVX4RZOP&keywords=Lens+Spanner+Wrench+Opening+Tool&qid=1699525031&sprefix=lens+spanner+wrench+opening+tool%2Caps%2C175&sr=8-3

[mistuk]

Thanks Peter

I’ve spoken with FLO  - even with the focus at its innermost it’s not in focus (needs to go in further)  - the chap at FLO has the same set up and he’s sent me a photo - my adapter isn’t in far enough…

thanks for the tip with hair dryer and cold water  I’ll try that!

 

 

[Franklin]

57 minutes ago, mistuk said:

trying to screw adapter into my straight thru finder so I can attach my ZWO camera. Bought the adapter from FLO - it’s definitely the right one, but can’t screw it in far enough to reach focus. 

I remember reading somewhere that the SW and Celestron finder threads are a different pitch and there are two different adaptors to cater for this. Your adaptor may have a different pitch thread to the finder body and that is why it could be getting stuck? 

[mistuk]

Just now, Franklin said:

I remember reading somewhere that the SW and Celestron finder threads are a different pitch and there are two different adaptors to cater for this. Your adaptor may have a different pitch thread to the finder body and that is why it could be getting stuck? 

Ooh thanks for this - I will check again with FLO…

[Franklin]

Modern astronomy used to sell them both and made a distinction between the two.

[Franklin]

Sky-Watcher & Clones to T thread Adapter for Straight Through Finders (modernastronomy.com)

Celestron 1mm T Thread Adapter for Straight Through Finders - Modern Astronomy

[Franklin]

28 minutes ago, mistuk said:

Tips on how to loosen it (before it goes in the bin!)

The flat ends of a lens spanner in the two holes and a rubber glove to grip the finder body and heating with a hair dryer will help.

[mistuk]

Consensus is that it is probably a different thread! so huge thanks to @Franklin for pointing that out.

Also, pleased to report that I have now separated the adapter from the finder! 🙂

Thanks all! 🙂

 

[Carbon Brush]

Thank you @Franklin. I learn something new every day on SGL.

The fine pitch threads on astro kit can give problems - even when correct.
Before assembly you can use a bit of silicone (electrical) grease or petroleum jelly. AKA vaseline - other brands are available and all that.
This is helpful a few years down the line if things have corroded, or if the metals 'gall'.
How much to use? It only needs be the slightest smear on the thread.
With either compound, work on the basis of it being a gold/platinum alloy and you are short of money😄
If you get carried away, there is risk of liquid vaseline in warm times, or blobs of grease falling on to glassware.

HTH, David.