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CG-5 tune up

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#1 Deetrix

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Posted 01 May 2014 - 05:59 PM

I'm tuning up the dec axis of my CG-5. I can't get the worm comfortably back on the dec shaft. Any suggestions? :help:

#2 Deetrix

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Posted 01 May 2014 - 06:16 PM

I should clarify. I have the worm back on the shaft. When it is back in its original position (fully at the top) it binds. Grease has been applied.

#3 roscoe

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Posted 01 May 2014 - 09:40 PM

photo? I have an older CG-5, which I tuned, but my memory of the work is vague, so with a photo, I, or someone here, will surely have a suggestion....
R

#4 Deetrix

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Posted 01 May 2014 - 09:48 PM

Thanks for the reply. I'll try to post a photo once I get the worm put back on the dec shaft. I took it off again to try to swap the washers at the top and bottom of the worm. (didn't work, they're slightly different sizes) I'm not understanding what's changed since I took the worm off the dec shaft two nights ago. Its like the worm shrunk or the dec shaft grew. I can't get it on the dec shaft by hand at all. Pretty much maxed out on frustration.

#5 Deetrix

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Posted 01 May 2014 - 10:00 PM

Here are a couple photos. The worm just doesn't rotate smoothly around the axis. Its very rough and it has a lot of metal to metal type binding. I don't know if the washer at the top is getting off to one side and losing function or what.

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#6 Deetrix

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Posted 01 May 2014 - 10:02 PM

Not sure these will do much good lol.

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#7 EFT

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Posted 01 May 2014 - 10:58 PM

That is not the worm. It is the wheel or the ring gear. If that is binding, then what you need to do is a little bit of sanding and polishing of both the inside of the ring gear and the outside of the axis casting to smooth them out. Once you do that, you should use only a very small amount of the appropriate grease in this area.

#8 Deetrix

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Posted 01 May 2014 - 11:53 PM

Thanks EFT! I will give that a try.

#9 roscoe

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Posted 02 May 2014 - 06:17 AM

I agree....likely there is a bit of metal that broke free and is stuck in between, or something scuffed up a little burr which is now binding it up. polishing all contact surfaces, as mentioned above, with perhaps 400-grit sandpaper, wet-or-dry paper works best, and you can lubricate it with water (after cleaning all grease off) to keep it from filling with metal dust, and if you want, you could go over it with 600 or 800 grit (though that may be harder to find) the paint section of an auto parts store is more likely to have fine paper than a big-box.

#10 Deetrix

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Posted 02 May 2014 - 01:10 PM

Thank you both. Sorry about the mix up on the names of the parts. After another hour of fiddling, I finally got it to turn somewhat smoothly. I've reassembled the dec axis and will do a complete set up tonight to see if the motor functions like it should. Wish me luck!

#11 Deetrix

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Posted 04 May 2014 - 10:59 PM

Here is the place thats giving me problems. Its the bottom of the dec shaft. Its binding with the bottom of the dec housing. I've put the mount back together three times that I thought I had it good, and each time it seizes up. I broke one of my rules and tried to fix something that wan't broke. I knew and acknowledged the risk, so that's all on me. At this point, I hope to salvage this mount so it can be used for visual observing and AP without dec guiding at all.

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#12 Deetrix

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Posted 04 May 2014 - 11:09 PM

Here is the damage.

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#13 EFT

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Posted 04 May 2014 - 11:29 PM

This is one of the biggest problem areas of the mount. The other one is on the other end of the DEC axis where it fits into the housing in much the same way only greater in diameter. And this is one of the worst things that can happen. You are going to need to smooth this as much as possible along with the surface on the inner part of the housing. Pits are OK, but the overall surface must be of a uniform height, otherwise it will never work. Be sure to check the upper surface of the axis casting as well as the surfaces on the inside of the housing since chewed up surfaces on the axis casting can easily mean chewed up surfaces on the housing surfaces and putting it back together without both surfaces being good will just destroy the work you have done. Clean everything very diligently because if you leave any sand paper grit or anything in there you will be back to square one.

I managed to get one a lot worse than this back to life once, but it takes a lot of work with fine sandpaper, polishing and good cleaning. Even then, if the axis casting no longer fits well in the housing (i.e., if there is too much side to side play, then the mount may not perform very well, but probably still OK for visual.

#14 Deetrix

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Posted 04 May 2014 - 11:48 PM

Thanks, Ed. It really has me stumped. It keeps tricking me into thinking its good. Then it locks up and I have to use excessive force to turn it so that I can access the retaining set screws that hold the ring nut. I think I'm taking a two day break from this. Again, thanks Ed.

#15 EFT

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Posted 05 May 2014 - 12:17 AM

Thanks, Ed. It really has me stumped. It keeps tricking me into thinking its good. Then it locks up and I have to use excessive force to turn it so that I can access the retaining set screws that hold the ring nut. I think I'm taking a two day break from this. Again, thanks Ed.


Taking a break from it is a good idea. When you come back to it you may see something that you were missing before. That's what I find when I get stuck on something.






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