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Celestron 2'' SCT adaptor ring stuck round the visual back of my new C9.25


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I bought rubber gloves today. I get a better grip, but it still won't move. I contacted the 'Widescreen Center' where I bought the diagonal but they haven't got back. I wish my first post here was more interesting but I'm hoping someone knows the solution.

 

Regards.

diagonal.jpg

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I'm assuming the threads have bound somehow, were they getting tighter as you were threading it together? Need to be careful with SCT threads as I've found they're not cut very well in my experience.

A boa strap wrench works wonders in this type of situation.

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12 minutes ago, Elp said:

I'm assuming the threads have bound somehow, were they getting tighter as you were threading it together? Need to be careful with SCT threads as I've found they're not cut very well in my experience.

A boa strap wrench works wonders in this type of situation.

I don't recall twisting it too tight, just enough to see it was secure. I'll look into the tool you recommend; I just hope it won't involve having to remove the focuser knob because I'm quite new to this size and type of scope.

 

Thanks.

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14 minutes ago, Cosmic Geoff said:

I'm not sure exactly what bit you are trying to unscrew, but if it's made of aluminium etc then heating it with a hot air gun should expand the ring and enable it to be unscrewed.  Don't heat up the focuser knob.

It's the grooved ring that the empty tube is sticking out of. I'm pretty sure it's best described as an adaptor. I think it's aluminium but I might be getting hold of a strap wrench today. If that doesn't work I'll try heat. Thanks

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I had this problem with my 8" SCT the first time that I attached an SCT diagonal to the 6.3 reducer - It possibly may be a function of differing temperatures from when it was put on to actual use with the cold constricting the threads which then caused it to "lock"....  I'm not sure.  However, a strap wrench (actually had to use two as the diagonal was stuck to the reducer so I needed something to grip strongly the reducer at the same time as the diagonal) sorted out the problem - after that I bought a Baader Click Clock visual back to avoid it happening again!  In fact, a strap wrench has saved my bacon many times for various things around the house so it's well worth having one!

Boa 13-2612 Standard Strap Wrench, 8 inch : Amazon.co.uk: DIY & Tools

 

Good luck!

 

 

Edited by Davesellars
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Or maybe pre-heat -treat the adapter with a hot flannel ... then allow to cool.....then reheat......

Several iterations and attack with the jar openers again.

One really stuck threaded adapter I had .......( that defeated all manner of techniques  )  somehow loosened itself on a window sill being left in the Sun for a week.

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1 hour ago, Craney said:

Or maybe pre-heat -treat the adapter with a hot flannel ... then allow to cool.....then reheat......

Several iterations and attack with the jar openers again.

One really stuck threaded adapter I had .......( that defeated all manner of techniques  )  somehow loosened itself on a window sill being left in the Sun for a week.

I'll see what happens to tea-towels when you microwave them. Hopefully nothing except warming them.

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Worst case scenario you could try stuffing some clean cloth down the neck of the opening in the back of the scope, making sure there is enough to be able to pull it out again. Get some very light oil with a fine neck (small Oil pens are available with small amounts of oil in) and squeeze some extremely carefully around the rim (marked with the dotted red line) where the two threads meet up. Wipe away any excess that might look as though it may go down into the scope itself. Let it soak down in the thread for a few hours, then see if you can carefully unscrew it after that. As long as the stuffing in the tube covers fully the width of the hole, and with very, very carefully placement of any thin oil it shouldn’t drip down into the inside of the scope. I would use this method as a last measure though only if all else fails. Can’t guarantee success but as a last measure worth a try.
C71338EA-012D-4701-AD64-5DAB2CA8165D.thumb.jpeg.89c2ca1e4fe783ef6c8a0bf7fbcb2944.jpeg

Edited by Knighty2112
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I've used one of these on a stuck visual back before with no issues, similar to the jar opener up there ^ but with better purchase and by design, better leverage. https://www.amazon.co.uk/gp/product/B00096JDK8/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

If all else fails, I tend to tap the outer knurled part with something metal, it has to be metal and don't ask me why. Sometimes the only way to free stuck threads is some gentle percussion mechanics. You are only looking to free up the mechanical bind between the threads, not do any damage. I would only do this as a last resort on an optical instrument myself.

The above is just advice, I'm not responsible for what you do to your own scope (yup it needs saying). Personally I would wait for  Widescreen Centre to get back to you.

 

 

Edited by Shed9
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  • 2 weeks later...
On 30/09/2022 at 11:24, Plantins said:

 

Great result!

Strap wrenches are brilliant for astro use, I've used mine quite a few times when adapters etc are stubborn to remove.

Yes. So good I wish I had more things to unloose with it.  

Edited by Westmoorland
typo
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