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Sears 4454 worth rescuing?

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#1 MikeCatfin

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Posted 06 May 2013 - 08:04 AM

So the other day I salvaged a Sears 4454 80mm F15 scope from being discarded. It is only the OTA with part of of the finder scope (rear element missing), no box, rings, eyepieces or mount. But for free I figured I'd give it a go. The glass looks ok, dirty but I think a good candidate for getting cleaned up. The tube has no dents but scratched up pretty good. The dew shield is dented, but I looked through the threads here and read how to get it back round, (I hope!).
Now I tried to unscrew the dew shield to get to the lens cell but was unable to; the whole unit unscrewed from the tube. I was thinking of possibly putting a few drops of Liquid Wrench on the outside of the dew shield to see if that would help( I already tried using a strap wrench but it didn't budge) but I'm concerned on the liquid contacting the lens. Any thoughts on how to get the lens out?
Also is this scope worth rescuing? Lastly I read where a few users replaced the original focuser unit with a Crawmach focuser; since I don't have any original eyepieces or diagonal would this be a decent mod to bring the scope up to the 21st century?
Sorry for the long and rambling post, but I appreciate any of all your ideas. (I do lurk in this forum often to see what you guys are up to).

#2 mustgobigger

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Posted 06 May 2013 - 09:13 AM

You can put a few drops on threads
...just be careful ....try 2 strap wrenches.
have someone hold assembly while
You work each end with straps.
I would lay a piece of foam on the grass
Or soft floor....and work close to
The foam just in case it drops.
Yea...its worth a rescue.
Optics are pretty good.

#3 BigC

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Posted 06 May 2013 - 12:49 PM

Sounds like the basis for a homebuilt Sears or you could sell to someone needing the OTA or objective.

#4 greju

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Posted 06 May 2013 - 01:05 PM

As strange as this may sound sometimes all it takes is a "light touch." There have been times I have cranked and cranked trying to loosen dewshields and I read here someplace to try the "light touch" approach and it has worked more than once for me. Other than that a rubber strap wrench on each piece, as has been mentioned, might work.

#5 MikeCatfin

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Posted 06 May 2013 - 01:36 PM

Thanks for the tips. I'll try the "light touch" first then if it fails get another strap wrench. I'll let you all know if I'm successful.

#6 Littlegreenman

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Posted 06 May 2013 - 01:43 PM

Regarding the dew shield. It is easy to cross thread them. Advice above is good.
I would recommend checking the optics before doing anything major, such as replacing the focuser. The optics generally good, but it may have acquired some damage over time. My thinking is if you find out the optics have issues, you may not want to be buying aftermarket focusers.
If the optics do not test good at first, then check collimation and fix if needed. If that doesn't work, then check collimation a second time....(been there, done that).
If that doesn't work, then the optics may need to be taken apart, spacers checked, try rotating the elements, might as well clean the inside too, etc. Do not attempt this without really reading up it. (Been there, done that).
Even if you find there are issues with the optics you can't fix, you can sell the tube or parts as-is. Somebody out there will probably buy anything, even bad optics.
LGM

#7 teddyk1

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Posted 06 May 2013 - 11:44 PM

How about some pics
The optics are excellent in these
They were in mine

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#8 MikeCatfin

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Posted 08 May 2013 - 07:49 AM

How about some pics
The optics are excellent in these
They were in mine


The scratches on the tube didn't show up well (took the pics with an iPhone) but you can easily see the dented dew shield and dirty lens.
Here are a few pics of the scope:

Posted Image

Posted Image

Posted Image

Posted Image

#9 snork

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Posted 08 May 2013 - 09:34 AM

Posted Image The dew shield in my pic was not quite as bad as yours but it had a good dent in it. I was able to put it in a small set of sheet metal rollers and roll it back to it's original form without damaging the threads in about 5 minutes. So if you have access to rollers or know someone who works in a fab shop, that maybe a way to fix your shield.

#10 MikeCatfin

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Posted 09 May 2013 - 07:30 AM

Hi Dan, that came out great,but unfortunately I don't have access to a set of rollers.
But having gone through a couple of threads here I did see a post where someone (I forgot who) made a wooden circular jig the diameter of the dew shield and tapped it through to round it out. Since my band saw needs a new motor, I had to come up with something else. I noticed that the 7lb. Losmandy weight fit inside the shield almost perfectly I slid it in through the threaded side then with a rubber mallet tapped the sides until it rounded out. I believe I got it to about 99% round.
Posted Image

#11 MikeCatfin

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Posted 09 May 2013 - 07:35 AM

Now that I have removed the dew sheild with a little help of Liquid Wrench and a strap wrench my next question is this:
Can the lens cell be removed from the bottom half of the lens cell holder that screws onto the tube? If so how? I apologize in advance if this is an elementary question but
having never dismantled a scope before I'll have questions as I go along.

Posted Image

#12 snork

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Posted 09 May 2013 - 09:51 AM

Mike, your dew shield looks great, glad you found a solution.

#13 bremms

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Posted 09 May 2013 - 12:05 PM

Just loosen the collimation screws. The pull screws are holding the cell to the tube flange (counter cell) Take the three screws out that are down tight and it will come right apart. Good job fixing the dew shield!

#14 MikeCatfin

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Posted 09 May 2013 - 12:37 PM

Thanks Dan!
@ bremms - thanks for the info - as said never tried this before so I don't want to make a stupid mistake! Once I get the lens out and clean it up a bit I'll put it back together to test the view. (after I either find or make some rings for it - 90mm??)

#15 stevecourtright

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Posted 09 May 2013 - 12:58 PM

Don't make the mistake I did - be sure to come up with a scheme to keep the elements oriented properly when reassembling and the spacers as well.

As soon as I got my classic apart I got so excited to see the lens clean, I clean forgot how they went together.

#16 MikeCatfin

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Posted 09 May 2013 - 03:30 PM

Don't make the mistake I did - be sure to come up with a scheme to keep the elements oriented properly when reassembling and the spacers as well.

As soon as I got my classic apart I got so excited to see the lens clean, I clean forgot how they went together.


Good tip, thanks!

#17 MikeCatfin

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Posted 10 May 2013 - 07:47 AM

I think the objective cleaned up nicely.

Posted Image






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