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Need help with CG5-GT RA motor gear.....

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#1 budman1961

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Posted 15 May 2013 - 08:41 PM

HELP!

I made a little mistake while working on my mount, and somehow broke a few teeth off of a white plastic gear on the RA motor. As I mentioned, this is from a Celestron CG5-GT, the label on the motor says 20080806.

It is the bottom most gear, out of the 4 gears located on the motor.
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Im thinking maybe there is a CN'er that might have a dead RA motor laying around somewhere, or it could be salvaged from a dead mount.

I sure could use a hand with this one......Celestron wants 132.00 for a new motor assembly......I only need 1 small part!

If anyone has a contact name/email address for someone at Celestron parts, I could pursue that avenue also.

I am willing to pay for the part, if someone has a spare RA motor that works, maybe we can work something out.

Thanks for looking!

Andy

#2 pjensen

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Posted 15 May 2013 - 08:54 PM

You might find a replacement here on McMaster.

Good luck. By the way, how did it get broken?

#3 budman1961

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Posted 15 May 2013 - 09:24 PM

Thanks for the link! I had successfully cleaned up the DEC axis, de greased/polished, etc.....and closed the mount up. A while later I decided to do the RA axis, and I took a foolish shortcut.......

I was following the guide on this site, his directions were great, my following them, well not so good.

The upside is both the RA and DEC are smooth as silk, only 1 axis is crippled by a 5 cent part, and a healthy dose of stupidity!

Andy

#4 rodney

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Posted 15 May 2013 - 11:39 PM

Andy,
I have had had huge success dealing directly with Celestron on parts. Send the images posted and I am confident that they will be able to help you.

Clear skies,

#5 budman1961

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Posted 15 May 2013 - 11:46 PM

Thanks Rodney, I will call them in the morning!

#6 Geo.

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Posted 16 May 2013 - 09:24 AM

Gears are rarely unique. What you have to do is get a count of the teeth and determine their pitch. These look like 24s, but you'll have to verify that. Material is Acetal. I've got a large collection of small gears If you get me the details on this I can try to match it.

Another option is:
http://www.gizmoszon...d_gear;ppinc=1a

As these motors are the same as used on the CGEM, you'd think this would be a common failure. May have to get some brass pinion stock and make up a few gears.

This may help:

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#7 budman1961

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Posted 16 May 2013 - 09:59 AM

George,

I did count the teeth, and there are 24. I dont have a way to determine the pitch though. The gear has another smaller gear molded on top of it also, it has 12 teeth.

Does that help?

Thanks for your help!

Andy

#8 Raginar

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Posted 16 May 2013 - 10:57 AM

Andy,

Call Ed at EFT or send him an email. I bet he knows the data you need.

#9 rmollise

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Posted 16 May 2013 - 12:18 PM

Thanks for the link! I had successfully cleaned up the DEC axis, de greased/polished, etc.....and closed the mount up. A while later I decided to do the RA axis, and I took a foolish shortcut.......

I was following the guide on this site, his directions were great, my following them, well not so good.

The upside is both the RA and DEC are smooth as silk, only 1 axis is crippled by a 5 cent part, and a healthy dose of stupidity!

Andy


Sorry this happened to you. Other than call Celestron, as others have suggested, see if Mr. Ed has any ideas, look for a hangar queen mount to use for parts, or try to source the gear.

Again, sorry this happened...but...this might be illustrative to other folks thinking of going down this road. The Astronomy Boy site is great, but it was designed, really, for the early non-go-to CG5/EQ-4 which was really rough mechanically and packed with lots of the Chinese glue-grease. Even the earlier Celestron CG5 _go-to_ mounts really don't need this done to them. If there is a specific problem, that is one thing, but doing the things on this website otherwise is not necessary and will rarely result in "more better gooder" with this mount. ;)

#10 Christopher Erickson

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Posted 16 May 2013 - 01:37 PM

That is a compound (two gears together) molded plastic spur gear and those things aren't available as generic, off-the-shelf parts.

Stock Drive Products is a good source for all kinds of gears.

Rush Gears can make just about any kind of replacement gear but they aren't cheap.

#11 budman1961

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Posted 16 May 2013 - 05:09 PM

A member on another forum has a dead DEC unit, and is shipping it to me. Ed was super responsive, he has the gear units for sale, and pointed out that the single plastic gear is designed to "break" if the mount is bound up.

He was kind enough to confirm that the RA and DEC gear units are the same.

This unit has a compatible gear box, however all the gears are metal, so one should be careful, and know the consequences before hand. It is shipped out of Florida, and the complete assy is 13 bucks. Another CN'er sent me a few links to threads, but I wasnt able to glean whether the motor is 100% compatible with the Celestron unit. 13 bucks vs 132.....

Rod, point well taken. I'm mechanically inclined, and have been rebuilding things for many years. That being said, I wasn't careful, and ended up binding the worm against the RA main gear, and voila!

The Astronomy Boy site si good, and yes, other than a brief mention of the newer mounts is geared to the non-motorized mounts.

The upside is that the DEC axis now isnt anywhere near as tight as it was before, and now, once my OTA is on the mount, I can actually balance it. The RA axis is quite smooth also.

The folks at Synta sure like to use lots of their grease....it has the consistency of very cold Vaseline..... it took a bit of time to get it all out, and was replaced with SuperLube.

Thanks for everyones help!

Andy

#12 Geo.

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Posted 17 May 2013 - 06:10 PM

Igarashi has an Indian division and the cheaper Celestron mounts use an Indian sourced motor. Gizmoszone only stocks one compound 12/24 gear

Part No.: GC0.5-12/24-20
Module 0.5
Pressure angle=20deg.
Teeth no.=12/24
Bore size=2.0mm
Material: Acetal

I've looked at the GC0.5-12/24-20 as a replacement for the ETX gear that often strips.

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#13 Geo.

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Posted 17 May 2013 - 09:08 PM

This may be the CG-5 motor:

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#14 budman1961

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Posted 18 May 2013 - 07:17 PM

So, what are the chances that those are the right parts?

Andy

#15 JoseBorrero

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Posted 18 May 2013 - 09:33 PM

Sorry to hear that Andy,
you should have handy a digital caliper, it will ease getting those measurement .






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