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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Cleaning CG-5 ASGT internal gears
      #6010466 - 08/06/13 10:30 PM Attachment (42 downloads)

My poor CG-5 sat through a dust storm and is making some small sandy crunching noises when I use the motors. Incidentally, there is no sand noise when I rotate the RA or DEC after loosening the black levers/locks and rotate those axes manually (without the motors/hand control).

At least as a first try, I just want to remove and clean the copper colored gears on the inside. My understanding is that I should apply a degreaser, then re-grease them with a synthetic grease. I'm not mechanically inclined so I have questions:
1) Is there a particular kind of 'degreaser' I should buy or is this just a generic product?
2) Is there a particular kind of (synthetic) grease I should buy?

Edited by sneutrino (08/06/13 10:35 PM)


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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6010484 - 08/06/13 10:37 PM

yeah sounds like your worm gear is what is crunching, not good and if you used it that way you could have damaged the teeth, if you only use the mount for visual its probably not a big deal, for AP it could give you problems.

degreaser, use whatever, the point is to clean it. its metal as long as you use something normal and not say acid you won't hurt it.

for re-greasing, a typical lithum grease would work fine. if you want it to be as smooth as possible i believe many recommend superlube, but grease is grease, you want something that stays in place well but is not so thick that it causes unnessisary stiction etc.


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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: frito]
      #6010497 - 08/06/13 10:39 PM

ah now your picture works. that is the reduction gear that connects the motor (the motor has a gearbox on it as well) to the worm gear. the motor's gearboxes are pretty well sealed so you can leave them alone but the worm gears are not very well sealed, if its still crunching after cleaning that reduction gear set you need to tear the mount completely apart to get at the worm gear systems. if you go that far you might just want to look at getting a hypertune kit that will replace various teflon bearings etc.

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pogobbler
professor emeritus


Reged: 09/30/08

Loc: Central Indiana, USA
Re: Cleaning CG-5 ASGT internal gears new [Re: frito]
      #6010755 - 08/07/13 01:58 AM

I recently tore down, cleaned, degreased and re-lubed my ASGT mount. It wasn't really a hard job, just keep track of where the parts go and you shouldn't have a problem. You can easily find step by step instructions with photos to tear down this and similar mounts just by doing a quick search. I used mineral spirits to degrease all the parts and used Super Lube to relubricate everything and it works like a charm. I found it to work much better than the lithium grease I used on an older CG5 mount. In fact, I ended up cleaning up and regreasing the old mount after I did the ASGT. I hadn't used the mount in a while and the axes were very stiff-- not quite frozen, but it wouldn't have been useable like it was before I cleaned and regreased it. Now, with the Super Lube, it works great and I anticipate it lasting a lot longer then the lithium grease did.

Edited by pogobbler (08/07/13 02:00 AM)


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: pogobbler]
      #6012129 - 08/07/13 07:06 PM

One of the two black hex screws in that small copper gear appears to be totally stuck so I'm going to try to clean it in place.

Does anyone know how to remove the larger of those pictured gears? I removed two hex set screws from it but it is still stuck.

I messaged Michael Harrison about fixing the pictures on his blog post - http://dragonseye.com/blog/2010/01/Re-greasing-a-Celestron-CG-5-mount/ - that may be useful.


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6012137 - 08/07/13 07:08 PM

I may have to clean and grease both of them 'in place'.

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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6012360 - 08/07/13 08:57 PM

its a brass gear and yea there are two in each one. it is metric, make sure to use the correct size. do not use standard hex keys on metric it WILL result in stripping if you strip it you will need to either drill it out carefully (very as its a brass gear, its soft metal) or probably a better idea find a small easy out that will fit into the hole to remove it. if care is taken it will come out with the right tools and some elbow grease.

I recently had to remove some extremely torqued down 3mm and 4mm hex set screws on one of our machines at my work, the 3mm came out with some effort and a T handle hex wrench, the 4mm set screws on the thing were torqued so good i had to use a 4mm T handle with a very LAEGE channel lock used to turn the T handle while the part was held in a vice! I really though it was a bad idea but I was careful and both broke free with a snap and were good to go!


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: frito]
      #6016204 - 08/09/13 04:42 PM

I ran the motors for less than 5 seconds so it should be pretty OK.

No idea how to get the brass gears off so I am leaving them on, but it is easy enough to take a lot of things apart and get to the worm gear so I cleaned those. Super lube multipurpose grease isn't arriving until Tuesday so I will update then.

Edited by sneutrino (08/09/13 04:44 PM)


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mclewis1
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6016325 - 08/09/13 06:20 PM

So the accepted plan is ... careful dissassembly (paying particular attention to the thin spacers which are usually present, they are often overlooked because of being "glued" in place with the old lube), good cleaning to remove the existing lube and any dirt, and then only small amounts of new lube during re assembly. The worm gear adjustment is checked by manually moving it through the ring gear's entire travel.

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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: mclewis1]
      #6021391 - 08/12/13 06:37 PM

The super lube arrived early and I finished the DEC section, but there is a point of concern. You know how the DEC should look like the 4th picture in this link http://astronomer.proboards.com/index.cgi?board=Equipment&action=display&... ? For example, the metal ridge on the shaft that you can see in the DEC sections polar scope window, this ridge is centered in the window. When I put mine back together and lined up the two index marks, it is 10 to 15 degrees off. Is this a problem? It might be because I was rotating the DEC via the worm gear while it was partially assembled.

Edited by sneutrino (08/12/13 06:38 PM)


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RTLR 12
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Reged: 12/04/08

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Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6021448 - 08/12/13 07:13 PM

There is nothing that you could have done that would have change the alignment marks. They are in the same place now as when you started. They are just an arbitrary starting position anyway. I removed the factory marks on my CG-5's and add my own marks in the proper locations.

Stan


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: RTLR 12]
      #6021539 - 08/12/13 07:59 PM

I didn't move the marks, but I must have moved some mechanical axis away from the default position.

So the index marks are truly irrelevant if I'm going to do a Goto alignment procedure anyway? Good.


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RTLR 12
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Reged: 12/04/08

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Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6021607 - 08/12/13 08:41 PM

They just give you a reference point to start your alignments from. I try to get the RA axis, using the CW bar, as vertical as possible and the dovetail parallel to the polar axis. Then I place my marks where I don't have to contort to see them. Then, because I use so many different scopes with my mounts, I just use them as a reference. They don't need to be exact.

Stan


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EFT
Vendor - Deep Space Products
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Reged: 05/07/07

Loc: Phoenix, AZ
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6022659 - 08/13/13 11:10 AM

Quote:

I didn't move the marks, but I must have moved some mechanical axis away from the default position.

So the index marks are truly irrelevant if I'm going to do a Goto alignment procedure anyway? Good.




Stan is correct. You probably never noticed the alignment of the hole before you dug into the mount. You will now notice things that you hadn't before since you are now more familiar with the mount. The marks are arbitrary, but it is most helpful if they are set so that the RA is vertical and the DEC is pointed straight forward because that is the general position that the mount assumes it is starting from. If you don't have the mount pointing that way to start, then the first alignment star will be further off, but after that it won't matter.


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obin robinson
Carpal Tunnel
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Reged: 10/25/12

Loc: League City, TX
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6022867 - 08/13/13 01:00 PM

Quote:

1) Is there a particular kind of 'degreaser' I should buy or is this just a generic product?
2) Is there a particular kind of (synthetic) grease I should buy?




1) The best degreaser I've ever used is pure isopropyl alcohol mixed with distilled water. It works great with multi million dollar aircraft and it works great with telescope mounts.

2) The best grease I've ever used is Militec-1:
http://www.militec1.com/grease11.html

It works great in everything from automatic weapons in the desert to heavy equipment in sub zero temperatures. It works awesome for telescope mounts too. It's what I use on all mount tuning operations.

obin


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: obin robinson]
      #6023493 - 08/13/13 05:09 PM

The RA axis is very sticky when unlocked. What could be the problem?
- No motor or worm gear attached yet.
- Made no change (no cleaning) to the ring of bearings near the polar scope end except for adding a tiny amount of super lube.
- Tried with a moderate amount of grease on the teflon ring, and with very very little grease on teflon ring.
- Tried with both orientations of the bearing ring thing (see 9th picture at http://astronomer.proboards.com/index.cgi?board=Equipment&action=display&... , the object with two concentric metal rings and black plastic between them). Everything on this item is rotating very smoothly though.


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RTLR 12
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Reged: 12/04/08

Loc: The Great Pacific NorthWest
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6023559 - 08/13/13 05:34 PM

Are you sure the clutch is not causing trouble? You may want to pull it apart and see where the interference is. Look for indications of gauldng. Are you just turning the shaft inside the ring gear or are you turning the ring gear and shaft together when it binds?

Stan


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: RTLR 12]
      #6023719 - 08/13/13 06:46 PM

Ok, so I can prescribe any level of stickiness that I want by tightening that stack of rings on the bottom near the polar scope. I guess that it isn't supposed to be tightened all the way, since that binds everything. The rings ought to be a little loose, then locked down onto the axis by tightening the 3 small set screws that bite into the lower threaded part of the axis.

But, I can't get the RA lock knob to have any effect as I play with different tightness levels via rings...


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6023720 - 08/13/13 06:46 PM

Is the clutch the thing that the lock knob controls?

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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6023802 - 08/13/13 07:32 PM

Oh, I get it now.

When the worm gear is in place, it holds onto the aluminum/geared part of the RA axis, which allows the two parts of the RA axis to move independently of each other when the lock knob is unlocked.


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RTLR 12
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Reged: 12/04/08

Loc: The Great Pacific NorthWest
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6023812 - 08/13/13 07:37 PM

.

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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: RTLR 12]
      #6024171 - 08/13/13 11:14 PM

Does anyone know what, if any, lubricant/grease is supposed to goes on the large aluminum cylinder (see 6th picture in http://astronomer.proboards.com/index.cgi?board=Equipment&action=display&... ) ? I'm having trouble with this on the DEC axis. I never actually removed the one on the RA axis so I had no problem.

With super lube synthetic grease on it, it is difficult to put on, and very resistant to movement when it's on. This is still true but to a lesser extent when I remove most of the super lube from it.

I wonder if it's supposed to have no lube , or a different kind of lube.

I also have Super Lube Dri-Film lubricant which is a WD-40 like solution, I might try that, but am interested to know if anyone has insight on this...

edit: I might use regular WD-40, I am not so sure about this dri-film stuff, as it leaves a fine teflon powder which has some not so nice properties.

edit2: Certainly the geared part of the cylinder should have grease. I'm asking about the rest of it.

Edited by sneutrino (08/13/13 11:39 PM)


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EFT
Vendor - Deep Space Products
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Reged: 05/07/07

Loc: Phoenix, AZ
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6024229 - 08/13/13 11:54 PM

Quote:

Does anyone know what, if any, lubricant/grease is supposed to goes on the large aluminum cylinder (see 6th picture in http://astronomer.proboards.com/index.cgi?board=Equipment&action=display&... ) ? I'm having trouble with this on the DEC axis. I never actually removed the one on the RA axis so I had no problem.

With super lube synthetic grease on it, it is difficult to put on, and very resistant to movement when it's on. This is still true but to a lesser extent when I remove most of the super lube from it.

I wonder if it's supposed to have no lube , or a different kind of lube.

I also have Super Lube Dri-Film lubricant which is a WD-40 like solution, I might try that, but am interested to know if anyone has insight on this...

edit: I might use regular WD-40, I am not so sure about this dri-film stuff, as it leaves a fine teflon powder which has some not so nice properties.

edit2: Certainly the geared part of the cylinder should have grease. I'm asking about the rest of it.




There are two problems here. First and foremost is the fit of the ring gear. The metal to metal surfaces on the gear and the axis casting must be sanded and polished to fit better and smoothly. Once that is done, then you can move on to lubing things and should use SuperLube for this. The Dri-Film might work if you already have it, but normal SuperLube all-purpose grease works just fine. The key is to use a very small amount. The best way to do that is to put some lube on the inside of the ring gear, slide it into place and turn it around a bit, then remove the gear and wipe the inside surface of the gear off. When you replace the gear again, as long as you didn't use too much lube in the first place, the remaining thin coating of lube is all you will need.

If you are having problems either getting things back together or having them be too stiff to turn, then there is a good chance you are not doing these things correctly. In addition, The metal to metal surface between the axis casting and the axis housing must be treated the same way. They need to be sanded a bit and polished and then a very thin coating of lube applied.

The DEC axis of the CG-5 is consistently one of the most difficult things that I tune up. There are so many metal to metal contact surfaces and no bearings that it is a constant struggle to get things moving and they rarely end up moving as freely as I would like. All the contact surfaces must be properly fit and move easily before any lube is applied and then after the lube it applied (even a thin layer) you may find that you need to go back and do more work.


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: EFT]
      #6024307 - 08/14/13 12:41 AM

I want to sand and polish it since it got nearly stuck twice with super lube grease, and then with the dri-film, which was stressful.

Should I use a silicon carbide sandpaper at 600 grit, then move to 1000 and 2500 grit?
http://home.howstuffworks.com/polish-metal-sandpaper.htm


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EFT
Vendor - Deep Space Products
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Reged: 05/07/07

Loc: Phoenix, AZ
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6024319 - 08/14/13 12:47 AM

Quote:

I want to sand and polish it since it got nearly stuck twice with super lube grease, and then with the dri-film, which was stressful.

Should I use a silicon carbide sandpaper at 600 grit, then move to 1000 and 2500 grit?
http://home.howstuffworks.com/polish-metal-sandpaper.htm




That's a good plan. You can even start with 400 but you probably don't need to go further than 1000 or 1200. Finish up with some aluminum polish when you are done sanding.


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: EFT]
      #6025969 - 08/14/13 08:48 PM

Everything is done, including the DEC, with some Dry-Film and a little grease, after sanding/polishing. The DEC is noticeably smoother with a quieter motor now.

I ended up adjusting the worm gear position set screws slightly, erring slightly on the side of allowing backlash, as opposed to letting the gears chew on each other.

Aside from cleaning the massive sand/dirt issue, I hope that I improved more things that I made worse. Mainly, the smaller brass gear on the RA is no longer in perfect condition. The larger gear has cosmetic damage so that I could get it back on. Those were hard to work with.


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Falcon-
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Reged: 09/11/09

Loc: Gambier Island, BC, Canada
Re: Cleaning CG-5 ASGT internal gears new [Re: EFT]
      #6026425 - 08/15/13 02:30 AM

sneutrino: Hope you do not mind a minor sidetrack here but...

Ed: Can I ask for a bit of clarification? You said:
Quote:

First and foremost is the fit of the ring gear. The metal to metal surfaces on the gear and the axis casting must be sanded and polished to fit better and smoothly. Once that is done, then you can move on to lubing things and should use SuperLube for this.



To me that sounds like you are suggesting the surfaces be dry test-fit prior to applying lubricant. I am assuming this is incorrect.... is it?


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EFT
Vendor - Deep Space Products
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Reged: 05/07/07

Loc: Phoenix, AZ
Re: Cleaning CG-5 ASGT internal gears new [Re: Falcon-]
      #6026430 - 08/15/13 02:46 AM

Quote:

sneutrino: Hope you do not mind a minor sidetrack here but...

Ed: Can I ask for a bit of clarification? You said:
Quote:

First and foremost is the fit of the ring gear. The metal to metal surfaces on the gear and the axis casting must be sanded and polished to fit better and smoothly. Once that is done, then you can move on to lubing things and should use SuperLube for this.



To me that sounds like you are suggesting the surfaces be dry test-fit prior to applying lubricant. I am assuming this is incorrect.... is it?




In general, dry fitting is a dangerous proposition and I do not recommend that people do it without taking great care. That said, I dry fit gears all the time to be sure that the everything is clean and there is nothing left in their to scratch things up and cause trouble. But I have a lot of practice and a good feel for how much things must be worked before it is relatively safe to dry fit. Even then, I am very careful and put things together slowly and evenly. It is important to have smoothed out the surfaces very well and polish them to a reasonable level before trying to dry fit. It is the rough, unpolished gears that may slide together and then get stuck.

Once again, the CG-5 DEC axis in particular is very difficult to deal with since there are no ball bearings for the ring gear or the axis casting to ride on. So it is possible to sand things too much. However, because most of the sanding and polishing must be done by hand I find that people get tired of doing that long before they get to the point that they have gone too far.

I hope maybe that cleared it up a bit.


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sneutrino
super member


Reged: 08/08/09

Loc: San Jose, CA
Re: Cleaning CG-5 ASGT internal gears new [Re: EFT]
      #6027199 - 08/15/13 01:36 PM

EFT, if you have seen the internals, would you say that the Celestron CVX, and CGEM have significant mechanical improvements over the CG-5?

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EFT
Vendor - Deep Space Products
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Reged: 05/07/07

Loc: Phoenix, AZ
Re: Cleaning CG-5 ASGT internal gears new [Re: sneutrino]
      #6031013 - 08/17/13 01:48 PM

Quote:

EFT, if you have seen the internals, would you say that the Celestron CVX, and CGEM have significant mechanical improvements over the CG-5?




Just got back in town.

The AVX does not have significant mechanical improvements over the CG-5 but does have some improvements that make it a better choice. The CGEM does have significant mechanical improvements over the CG-5 that put it in a different class of mount. Except for the use of ring gears in both mounts, the CGEM is significantly different from the CG-5 and would always be my recommendation when deciding between the two.


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