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Cleaning CG-5 ASGT internal gears

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#26 sneutrino

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Posted 14 August 2013 - 07:48 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.

#27 Falcon-

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Posted 15 August 2013 - 01:30 AM

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

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

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?

#28 EFT

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Posted 15 August 2013 - 01:46 AM

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

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

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.

#29 sneutrino

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Posted 15 August 2013 - 12:36 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?

#30 EFT

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Posted 17 August 2013 - 12:48 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?


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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