Help! Celestron Focal Reducer Jammed on Visual Back

[broadsword]

I ended last night's imaging session with my Celestron Focal Reducer completely jammed on the (removable) visual back from my C11. No amount of human force will get them unstuck. It happened once before but I finally managed to free them by hand, but no luck this time. I was being careful not to overtighten this time as well...

I've read a couple of blogs already on SGL and Cloudy nights indicating that this isn't uncommon, however the possible remedies (freezing/boiling water, loctiting the visual back on the scope) sound a bit drastic, so just reaching out to see if there are any other suggestions. Anyone know what Celestron have to say (haven't tried them yet)?

[billhinge]

do you mean the the f6.3 lens? I have one of these. I haven't seen the blogs you mention, do you have a reference?

Mine is screwed into a moonlight adapter

I assume you tried the obvious, try tightening it to break the friction then loosening by turning the opposite way?

[Mav359]

I have one of these they are great, its called a Boa-Constrictor Strap Wrench

http://compare.ebay.co.uk/like/280995498361?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar&cbt=y

Way back i had issues with my AZ bolt and this was the only thing that moved it, goes everywhere with my kit now, think you can gt them in B&Q if you dont want to wait for delivery

Hope you get that sorted

[broadsword]

Yes, it's the F6.3 FR, and It's not budging one bit in either direction. Have tried gently tapping, warming the outside ring, and everything else I remember from O-Level Metalwork. These are the blogs I read today:

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4514133/page/0/view/collapsed/sb/5/o/all/fpart/1

http://stargazerslounge.com/topic/154324-help-its-stuck/

[Merlin66]

+1 for the BOA

I'd try "squeezing" (gently!) the sides of the visual back in a vice with a couple of blocks -this can make the threads loosen their grip...

Then clamp it and use the BOA on the reducer......

[DoctorD]

Hi have a look on Amazon for Baby Boa strap wrench - I bought a pair for separating adapters and focal reducers.

Works a treat.

HTH

Paul

[pete_l]

And another vote for the BOA.

Exactly the same thing happened to me with my FR. After that little episode I lubricated the screw threads and haven't had a repeat problem.

[Davey-T]

Threads on astro gear always seem to be very dry when new. I use a silicone grease wiped on with a bit of kitchen towel.

Dave

[broadsword]

Very glad to report complete success! I purchased not one but TWO of the B&Q BOA equivalents, one of them the larger (150mm) size for the visual bACK, as I don't have a vice of any kind, and operated them in a counter-rotating fashion. Came apart surprisingly easily in the end. Nothing like gripping around 150 pound's worth of precision glass between the equivalents of two monkey wrenches. Many thanks for all the pointers to the BOA...

And now the tricky topic of lubrication...I saw silicone grease suggested by Dave above. I've also seen mention of coating the threads with graphite from a pencil. Anyone know the definitive answer?

Thanks again to all.

[Phil Fargaze]

Would a careful dab of vaseline do the trick, it`s cheap and there is usually a tub of it kicking around the house somewhere.

[Merlin66]

Hmmm,

Phil, I don't recommend vaseline it can soften and run....

My solution, going back 30 years is a VERY light smear of shoe polish (your choice of colour ;-) )

Works everytime.

[Ewan]

I had the same trouble but thankfuly mine didn't get completly stuck, it was snagging on each turn & the squeaky noise it was making was like my wheel barrow at work, i put 1 drop of 3 in 1 oil on a lint free cloth & ran it around the thread just once now no more jams & no squeaking

[kirkster501]

A bit of penetrating oil like WD40 perhaps - a few drops applied carefully?

[broadsword]

I had actually used WD40 a couple of times before the incident which started this thread. So I'm not sure it stays around for too long...

[Davey-T]

Silicone grease I use is from Wickes and made for lubricating push fit plumbing rubber O rings.

I just squirt a bit on kitchen towel and wipe round thread, only ever needed to do it once and the bottle will last a lifetime, as long as you don't start plumbing with it

Dave

[ollypenrice]

I have one of these they are great, its called a Boa-Constrictor Strap Wrench

http://compare.ebay....&var=sbar&cbt=y

Way back i had issues with my AZ bolt and this was the only thing that moved it, goes everywhere with my kit now, think you can gt them in B&Q if you dont want to wait for delivery

Hope you get that sorted

This is the answer. I also hear that boot polish on the threads is a way of avoiding the issue. When all else fails or the stuck item is too thin for the strap wrench I use one of those grips designed so that old ladies can open their jam jars. Indeed I find it handy for this as well despite being only a fairly old man! They can bite into your kit, though, so don't use them if you are precious about appearances.

Olly

Edit; Sorry Ken, you'd covered the boot polish already but I missed it.

[Merlin66]

Yeah, I get nervous about vaseline, oil, grease etc anywhere near optical surfaces....

Over time they can weep into the optics and cause even more problems.

Seriously, based on many years experience, the boot polish works, and works safely.

[Ags]

I agree with Merlin66. The problem with penetrating oil is it does just that - spreads out and gets places.

The only problem for me is that my household is a shoe-polish free zone... Shoe polish is sooo twentieth century. Next someone will suggest brylcreme :-)

[JamesF]

If boot polish works then perhaps beeswax is also worth a try. I know some divers use it for lubricating drysuit zips.

James

[Ewan]

I thought WD40 acts like a degreaser which is why i don't use it and it disipates too quickly for any long term benefits

[scarp15]

I use small quantities of lithium grease on screw threads, I work this in using my finger tips.