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Help! Collimation screw broke...

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#1 cloe

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Posted 05 April 2005 - 09:02 AM

Gentleman I need help.How do I repair a broken collimation screw{please note attachment}Snapped off during cold weather transport.Half the screw is still inside. :confused: :bawling:

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#2 Strgazr27

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Posted 05 April 2005 - 09:47 AM

Well, you could drill the screw out to accept what is called an E-Z out. I know, drilling near the corrector is a gut wrenching experience.

You could remove the corrector, remove the secondary holder from the corrector and drill it out that way.

You could try a pin sized drop of Super glue. Hold the head of the screw, if you still have it on the threaded part for a few seconds. See if it would be strong enough to back out the screw with no forces acting against it.

Other than that I can't help. I'm sure there are others with better ideas.

#3 garyc11

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Posted 05 April 2005 - 10:53 AM

you could try backing off the other screws untill they are loose, dont back them out all the way, see if you can move the screws untill the broken one sticks out then maybe you can get something on it maybe needlenose or something and back it out. or maybe expand the hole somehow and see if you can thread something on it with some locktight and try to back it out. if all else fails you will have to take it apart and get it out that way. good luck

#4 Starman1

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Posted 05 April 2005 - 02:53 PM

Gentleman I need help.How do I repair a broken collimation screw{please note attachment}Snapped off during cold weather transport.Half the screw is still inside. :confused: :bawling:

You aren't going to like my answer, but here goes:
1) remove the pressure plate that holds the corrector plate in place, and, gripping the secondary mirror cell, pull the corrector plate and secondary from the tube.
2) Cover the end of the tube with a bowl cover or the tube cap.
3) Carefully pack the entire corrector + secondary in a well-padded box after wrapping the whole thing in several inches of cotton batting. Use bubble wrap if you have it, and or foam rubber. Make it so well protected you can drop the box without hurting anything--because it will be dropped.
4) Call Celestron customer service at 310-803-5955 between the hours of 8 and 4 Pacific time and let them know it's coming and why.

Or, if you're more mechanical than that, remove the corrector, remove the collimation screws, remove the secondary w/backing from its cell, remove the broken screw stub, reinsert the secondary in the same orientation back into the secondary cell, thread 3 new screws in (the other 2 may be on the verge of breaking), remount the corrector, recollimate and you're done.

I think the screw is likely to be too small and too hard to use an easy-out. Plus, you don't want all the fine metal shavings to be there.

This is a problem, but not a fatal one. Your scope will be down for a little while, but not long. If you're in a hurry, send the corrector back by 2-day service, and authorize the return the same way. You'll be down only about a week that way.

#5 southmike

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Posted 05 April 2005 - 03:34 PM

I usded an easy out on a small ..very small hex head allen on my orion focus knob...but i also used a drill press to controll speed and deapth..and the allen screws have fewer threads...

go to sears and look for the easy out or screw extractor..
it is a kit with a few diff sizes...one part is a drill with very shallow deapth (just a cutter head)
the other is a tapered revers threaded screw..

very, very carfully drill center..and then change to extractor put that in apply slow speed and it should come right out...if your still very worried send it to the company..above all else take your time and be careful of the glass..

#6 Bluemeanie

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Posted 05 April 2005 - 03:42 PM

Good tip with the super glue. I would try that first. see if that will work before drilling.

#7 cloe

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Posted 05 April 2005 - 11:36 PM

Gentleman...thank you all for the information but bottom line I,am screwed(pardon the pun}.Assessing the situation the glue concept is a No Go...Starman yes,but gutsy.So I phoned Celestron to get their opinion.There response was immediate and thorough....{i:m screwed}.First off they immediately noticed the after-market product and suggested to send it back home for them to repair...no choice.So now it is the question of shipping and cost...don:t forget gentleman that I live in the great white north. :crazy:So just out of curiosity,how much do think this ordeal will cost...mind you the actual cost of repair is a blessing{thank you Celestron}but let:s talk shipping,duty and every other conceivable idea to charge. :question:

#8 Starman1

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Posted 05 April 2005 - 11:59 PM

When you send the corrector+secondary back to them (don't even think about sending the entire scope), insure it, and send it 3rd day FedEx, a reasonable freight rate (it'll arrive on time). Don't use UPS. They don't do as well with fragile packages.
Mark the outside of the package with "US product being returned to the manufacturer for repair". That way no hassles for Celestron.
Request it to be shiped back to you the same way. Give the Celestron people your credit card number OVER THE PHONE to charge you for the repair and return shipping.
They should turn it around in a couple days. You shouldn't be without for long.
The corrector plate has a mark on its edge that matches up to a mark on the telescope (you'll see it when you take off the plastic ring that holds the corrector in place). There are little spacers between the corrector and its cell. Draw a picture (or take one) of where these things are so they are put back exactly when you replace the corrector later.
When you put the corrector back, just line up the marks and rescrew the plastic pressure ring in place. Easy.
You will have to collimate the scope once the corrector+secondary is remounted, but it should be OK. It sounds like you know how to do that if the screws don't break.
Celestron will use their standard, hex-head, screws, so be sure you have an allen wrench that fits.
Peace.

#9 southmike

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Posted 06 April 2005 - 01:51 AM

excellent advice starman..
one more thing..you might want to tilt your ota down to fight dust getting in since it will be wide open now..
not sue of the best way to protect..saran wrap?

..hmmm that almost sounds like it was spoken from expierence..but you live in LA

#10 garyc11

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Posted 06 April 2005 - 10:09 AM

if the scope needs a cleaning this would be the time to have it done,you have to send it to them anyway. this way they can take it apart if you are not comfortable doing it.

#11 Starman1

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Posted 06 April 2005 - 11:16 AM

excellent advice starman..
one more thing..you might want to tilt your ota down to fight dust getting in since it will be wide open now..
not sue of the best way to protect..saran wrap?

..hmmm that almost sounds like it was spoken from expierence..but you live in LA

Tip the tube UP to remove the corrector. Cover the open end with saran wrap and reinstall the front cover. Store the tube assembly with the front down so internal dust falls on the saran wrap.
I worked in a mail-order business for 27 years, so am familiar with the ins and outs of shipping.

#12 Starman1

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Posted 06 April 2005 - 11:21 AM

if the scope needs a cleaning this would be the time to have it done,you have to send it to them anyway. this way they can take it apart if you are not comfortable doing it.

If it's over 15 years old, a complete overhaul is probably a nice thing to do, but sending the scope 2 ways and paying for the overhaul will probably cost him as much as a newer, used, scope would. Any dust on the primary can be blown off, and Celestron will likely clean the corrector before they send it back.
If it's an older scope, the mirrors could probably use re-coating, too, but, at some point, the law of diminishing returns takes over.
At this point, the simplest thing is to return the corrector + secondary.

#13 oldsalt

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Posted 09 April 2005 - 10:24 AM

You could try to file a small slot in the remaining stub with a jewelers file. I've had to do this on electronic equipment before. You could also see if a machineshop in your area could do the extraction of the offending stub instead of sending it to Celestron.

Best of luck with this.

#14 Rcade

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Posted 09 April 2005 - 03:43 PM

I would not recommend the super glue. No matter how careful you are if you get any on the threads it will be that much harder to get the screw out. I noticed the after market screws. Any chance that they contributed to the problem. Was the screw broken/twisted while trying to adjust it? If so it will be very dificult to remove. The best approach would be an easy out or trying to tighten the other scews enough to get enough of the broken one exposed to extract it. Sears makes some very small easy out type extractors. Just my opinion. Good Luck !!!!!!!

#15 cloe

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Posted 10 April 2005 - 11:00 PM

The concern given is very much appreciated but I must agree with Starman 1...so off the scope goes{Celestron recommendation}Let;s say we packed it extremely well and payed 100 CDN to ship....sent April 11...my hope is for the best and I will keep you informed. :shrug:


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