Can't undo 2 inch compression ring adapter

[matt_baker]

I'm unable to unscrew the compression ring adapter on my focuser to be able to have a threaded connection to mitigate tilt.

I've tried a strap wrench, soles of shoes, rubber gloves, table tennis bats but it's that tight that it just won't come undone.

Has anyone got anymore ideas how to get it undone?

[shirva]

Hot water r bottle,, get some heat into it,, and try what tried previously 

[johninderby]

Put it in a ziplock bag and put the whole thing in a bowl of hot water for a few minutes. Is it a Baader adapter I have found the thread can lock up solid. 

[bottletopburly]

You could probably localise heat using a clean soldering iron 

[matt_baker]

27 minutes ago, johninderby said:

Put it in a ziplock bag and put the whole thing in a bowl of hot water for a few minutes. Is it a Baader adapter I have found the thread can lock up solid. 

It's the actual focuser adapter that screws in

[johninderby]

The thread on the drawtube is a female thread.Perhaps a hairdryer would be more suitable.to apply a bit of heat.

Edited August 21, 2020 by johninderby

[matt_baker]

Just tried heating it up with a hairdryer until hot and trying with the strap wrench but that still doesn't work

[johninderby]

Perhaps remove the thumbscrews and the brass compression band and stand the end in hot water. 🤔

[Guest]

Is there a chance that it's cross threaded? 🤔

[Pixies]

Perhaps you could replace one of the screws with a longer bolt and use that for extra leverage?

How about standing it up on the adapter end, stuffing it full of kitchen towels, then gently applying a little Plus-Gas to the joint? Leave it for a few hours then try again. Obviously you need to be careful about where the stuff goes.

Also - if it starts to get to the desperate stage, is the adapter sacrificial? You could hold it in a bench vice and then use the strap wrench to turn the body.

[david_taurus83]

You tried heating the drawtube only and not the ring? Might need a bit more than a hairdryer.

[steveex2003]

Heat and expansion.

If that fails and all mechanical attempts prove futile, you could with great care and a Dremel-type tool, make two incisions to the adapter internally at 90 degrees to the threads. Cut through as close as possible to the threads without actually hitting them. Then with a narrow bladed screwdriver or similar try and crack the incisions remainder right through the threads of the adapter. If you're successful on both incisions you should be able to remove the section between the incisions and then the remainder of the adapter, either by simply unscrewing (if not cross-threaded) or by squeezing the opened ends of the adapter slightly.

Edited August 21, 2020 by steveex2003

[teoria_del_big_bang]

I would have thought a strap wrench would put the most force on it if there is enough width for it to grio on.

Steve

[matt_baker]

The most pressure I was able to apply was just after I made it very hot with the hairdryer was have my dad take one strap wrench and turn that clockwise at the bottom while I go from the top and turn anti-clockwise. I put all my arm grease into that, and it still didn't budge at all.

This might be me being stupid but surely if you heat it and make it expand, will it lock the threads together more?

Edited August 21, 2020 by matt_baker

[johninderby]

Heating will break the bond as the smaller part expands more than the larger one.

Had a Baader filer that just couldn’t be removed from a nosepiece but putting in hot water for a few minutes it came apart quite easily.

Edited August 21, 2020 by johninderby

[Tomatobro]

The idea of heating the ring is to take advantage of the aluminium expansion between the two effective diameters,

If it were on my bench the first thing I would do is to remove the focuser from the scope. Then buy an aerosol of Freezer spray, the sort that is used for PCB electrical fault finding (sometimes freezing a bad transistor can make it spring into life).

get set up and heat the adapter, then spray the freezer onto the inner ring and then quickly see if it will budge. It might be worth just spraying the inner ring and chilling it down and see if it will budge first before warming it up. The freezer spray is about £8 or so.

Its er been a while since I purchased a can of this spray and its a bit more than £8. Screwfix do a pipe freezer spay but its £24 a can

Edited August 21, 2020 by Tomatobro
new data

[matt_baker]

Would it be also worth to put it in the freezer for a few hours and try then?

[Seelive]

Sounds like a case of galling, where the two parts become effectively welded together. Certainly a problem with fine threaded aluminum parts (but normally anodising prevents it until the anodising becomes worn). If it is, I suspect brute force is probably your only option. If both parts are made of the same material, then unless you use very localised heating/cooling both bits will expand/contract at the same rate so I suspect it won't be very effective but the heating/freezer spray method suggested by Tomatobro above may work. Best of luck!

[matt_baker]

Just had a go again and ended up snapping something on the end, although I don't think it was a critical part, just a ring threaded on the opposite end of the focuser. 

I'll just have to cope with the fact that I'll probably never get it undone, but oh well, living with a bit of tilt won't be the end of the world

[The Admiral]

2 hours ago, matt_baker said:

Would it be also worth to put it in the freezer for a few hours and try then?

I had a similar experience and for the same reason with what looks very much like the same focuser and a compression ring but was fortunate that a strap wrench, IIRC, did get it apart but it needed a bit of an impulse to get it moving rather than a steady force. You need to be careful not to strain the focusing mechanism of course. A while ago now though, and memory is a little vague.

I would have thought that you'd need to cool the male part relative to the female part, to get differential expansion. Could you put some ice cubes in a freezer bag and insert that up the orifice, and try to separate before the outer female thread has had much chance to itself cool down?

Perhaps contact TS Optics to see what they recommend?

Good luck

Ian

PS. Sorry to hear that you may have damaged something, not sure what you mean by a ring at the other end of the focuser.

[spillage]

Not sure how thick the adapter is but maybe a oil filter chain and cloth or a steel lid remover. The lid remover has got me out a bind more than once.

https://www.ebay.co.uk/itm/Multifunctional-Stainless-Steel-Can-Opener-Bottle-Jar-Lid-Remover-Kitchen-Tool/174360716808?hash=item2898b56608:g:Rf0AAOSwHfBfGnz0

[The Admiral]

45 minutes ago, matt_baker said:

Just had a go again and ended up snapping something on the end, although I don't think it was a critical part, just a ring threaded on the opposite end of the focuser. 

I'll just have to cope with the fact that I'll probably never get it undone, but oh well, living with a bit of tilt won't be the end of the world

I presume that is there to prevent the draw tube sliding right through.

Ian

[matt_baker]

1 minute ago, The Admiral said:

I presume that is there to prevent the draw tube sliding right through.

Ian

Ah yes, I suppose so. Well now it's just a bent piece of metal so can't do much about that 😕