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Equipment Discussions >> Mounts

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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Pathetic CG-5 latitude adjustment bolts new [Re: FlyBD5]
      #5942804 - 06/27/13 10:01 AM

I just tried this, tightening one bolt against the other, and indeed it gets tight. But if you have the slightest mechanical sympathy you stop before things bend. It takes a lot of force to bend this 8mm bolt.

Now you seem to have applied even more force, trying to force a bent bolt through a straight hole, and as a result have broken the bolt. If it hadn't broken you would probably have stripped the thread.

Your best option is to find a local engineer who can drill the wreckage of the bolt out and, if necessary, retap the hole in the mount, possibly fitting a helicoil thread insert.

It might also be possible to screw the broken end of the bolt into the mount - with the other bolt removed to give room - and so remove it inwards. Even so the threads in the mount are probably in a bad way now so fitting helicoils may still be a good idea.

Chris


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FlyBD5
sage
*****

Reged: 02/12/13

Loc: Boston MA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: cn register 5]
      #5942874 - 06/27/13 10:45 AM

Quote:

I just tried this, tightening one bolt against the other, and indeed it gets tight. But if you have the slightest mechanical sympathy you stop before things bend. It takes a lot of force to bend this 8mm bolt.

Now you seem to have applied even more force, trying to force a bent bolt through a straight hole, and as a result have broken the bolt. If it hadn't broken you would probably have stripped the thread.

Your best option is to find a local engineer who can drill the wreckage of the bolt out and, if necessary, retap the hole in the mount, possibly fitting a helicoil thread insert.

It might also be possible to screw the broken end of the bolt into the mount - with the other bolt removed to give room - and so remove it inwards. Even so the threads in the mount are probably in a bad way now so fitting helicoils may still be a good idea.

Chris




You don't seem to understand what happened. Try to focus on what I said, rather than what you think I said. The bolts worked fine until they got bent by the normal movement of the head. I didn't find them tight or hard to turn until after they got bent. As I said, I have worked with aviation-grade hardware all my life. I know exactly how not to abuse a bolt. The thread is fine, precisely because I know how to do this kind of work. No helicoil or any other repair is needed there. And if you had read the thread before commenting you would have seen that the piece of the bolt is inside the knuckle joint (because I threaded it in rather than risking damaging the thread using an extractor), which is why I am asking if anyone knows how to take it apart.

If I could get an answer to that question, rather than all sorts of ruminations and creative stories about what happened, I would appreciate it.


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FlyBD5
sage
*****

Reged: 02/12/13

Loc: Boston MA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: Cliff Hipsher]
      #5942876 - 06/27/13 10:46 AM

Quote:

Quote:

They should be used before the saddle is loaded with a payload. With lots of counterweight and a heavy payload the thin bolts are doing a fair amount of work when being turned. Unloaded it should be almost impossible to bend or break one.

- Jim




OK, so I'm doing a 2 star (Polar) alignment with my LXD75. I have the mount in the Polar Home position, I press Enter, and the mount slews to Polaris. I hear a beep and the handbox prompts me to use the alt and az bolts to adjust the mount to get Polaris centered in my eyepiece.

My question is, if I'm not supposed to use the adjustment bolts with an OTA mounted, how do I get Polaris centered in the eyepiece?




Exactly.


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RTLR 12
Post Laureate
*****

Reged: 12/04/08

Loc: The Great Pacific NorthWest
Re: Pathetic CG-5 latitude adjustment bolts new [Re: FlyBD5]
      #5942898 - 06/27/13 10:59 AM Attachment (9 downloads)

Juan,

Pry the plastic covers off the the wedge axis and you will find the pivot bolt.

Stan


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: Pathetic CG-5 latitude adjustment bolts new [Re: FlyBD5]
      #5942913 - 06/27/13 11:06 AM

Quote:

You don't seem to understand what happened. Try to focus on what I said, rather than what you think I said. The bolts worked fine until they got bent by the normal movement of the head. I didn't find them tight or hard to turn until after they got bent. As I said, I have worked with aviation-grade hardware all my life. I know exactly how not to abuse a bolt. The thread is fine, precisely because I know how to do this kind of work. No helicoil or any other repair is needed there. And if you had read the thread before commenting you would have seen that the piece of the bolt is inside the knuckle joint (because I threaded it in rather than risking damaging the thread using an extractor), which is why I am asking if anyone knows how to take it apart.

If I could get an answer to that question, rather than all sorts of ruminations and creative stories about what happened, I would appreciate it.




All you need to do is remove the plastic caps off both sides of the mount base. Under there you will see the bolt that attaches the mount base and acts as the axle. Remove that and you will be able to remove the base and get access to the inside where the bolt is. You may have to be a bit creative to get in there to either cut it off or thread it completely through, but that's the method for removing the bent bolt. Ben there, done that.


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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Pathetic CG-5 latitude adjustment bolts new [Re: FlyBD5]
      #5942929 - 06/27/13 11:14 AM

I have flown and instructed on aircraft all my adult life. I hope you never work on any aircraft I fly.

You said yourself that you broke the bolts trying to remove them. Your best option is to contact Celestron. I doubt you can do this yourself. And your policy of insulting everyone who responds is unlikely to cause you to get much help.

Chris


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FlyBD5
sage
*****

Reged: 02/12/13

Loc: Boston MA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: RTLR 12]
      #5942940 - 06/27/13 11:21 AM

Thank you, Stan and Ed. The piece of the bolt is inside, already dropped in. I carefully thread it in with a screw long enough to reach so I can remove it. Much appreciated.

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spencerj
Pooh-Bah
*****

Reged: 11/17/04

Loc: Londonderry, NH
Re: Pathetic CG-5 latitude adjustment bolts new [Re: FlyBD5]
      #5942942 - 06/27/13 11:22 AM

Quote:

Quote:

Quote:

They should be used before the saddle is loaded with a payload. With lots of counterweight and a heavy payload the thin bolts are doing a fair amount of work when being turned. Unloaded it should be almost impossible to bend or break one.

- Jim




OK, so I'm doing a 2 star (Polar) alignment with my LXD75. I have the mount in the Polar Home position, I press Enter, and the mount slews to Polaris. I hear a beep and the handbox prompts me to use the alt and az bolts to adjust the mount to get Polaris centered in my eyepiece.

My question is, if I'm not supposed to use the adjustment bolts with an OTA mounted, how do I get Polaris centered in the eyepiece?




Exactly.




You get it very, very close with a Polar scope before you mount the OTA. If the Polar scope is used properly, very little adjustment would be needed. We are talking about fractions of a turn as opposed to cranking on the bolts 8-10 times.


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FlyBD5
sage
*****

Reged: 02/12/13

Loc: Boston MA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: cn register 5]
      #5942943 - 06/27/13 11:24 AM

Quote:

I have flown and instructed on aircraft all my adult life. I hope you never work on any aircraft I fly.




I have plenty of customers around the world, so I can afford to be very choosy. You don't qualify. Find someone else.


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hottr6
Carpal Tunnel
*****

Reged: 06/28/09

Loc: 7,500', Magdalena Mtns, NM
Re: Pathetic CG-5 latitude adjustment bolts new [Re: FlyBD5]
      #5943116 - 06/27/13 01:29 PM

Quote:

Quote:

I spent $5 and replaced them with something better. Now I don't have to complain about them any more.

Stan




Where'd you get those? I'm definitely heading to Home Depot tomorrow for some grade 8 hardware.



Anything with a handle is not Grade 8, almost by definition.

And I don't think Grade 8 will work... doesn't the CG5 use metric?


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RTLR 12
Post Laureate
*****

Reged: 12/04/08

Loc: The Great Pacific NorthWest
Re: Pathetic CG-5 latitude adjustment bolts new [Re: hottr6]
      #5943194 - 06/27/13 02:16 PM

Shane,

How about metric grade 10.9? That's the metric equivalent to grade 8 std. It's only nomenclature.

Stan


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FlyBD5
sage
*****

Reged: 02/12/13

Loc: Boston MA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: RTLR 12]
      #5943325 - 06/27/13 03:44 PM

Quote:

Shane,

How about metric grade 10.9? That's the metric equivalent to grade 8 std. It's only nomenclature.

Stan




Correct, if it's a metric bolt (I haven't looked at it that closely) then it should be a 10.9 which is equivalent to grade 8 in proof load as well as tensile and yield strength.


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FlyBD5
sage
*****

Reged: 02/12/13

Loc: Boston MA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: hottr6]
      #5943327 - 06/27/13 03:47 PM

Quote:

Anything with a handle is not Grade 8, almost by definition.




Well, that's true if the handle is made of the same material and stamped the same way, I suppose, but if you take a strong bolt you can also injection mold the handle or knob over it. Where there's will, I'm sure there's a way.


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Cliff Hipsher
Pooh-Bah
***

Reged: 12/31/08

Loc: North Chesterfield, VA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: spencerj]
      #5943469 - 06/27/13 05:19 PM

Quote:


You get it very, very close with a Polar scope before you mount the OTA. If the Polar scope is used properly, very little adjustment would be needed. We are talking about fractions of a turn as opposed to cranking on the bolts 8-10 times.




Talk about a "DUH!" moment. This makes perfect sense. Now I'm wondering why this is not covered in the manual?


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hottr6
Carpal Tunnel
*****

Reged: 06/28/09

Loc: 7,500', Magdalena Mtns, NM
Re: Pathetic CG-5 latitude adjustment bolts new [Re: RTLR 12]
      #5943536 - 06/27/13 05:57 PM

Quote:

How about metric grade 10.9? That's the metric equivalent to grade 8 std. It's only nomenclature.



Stan,

Yep, 10.9 is sort-of similar to Grade 8, but in metric.

Alas, it is not just nomenclature. There are very different standards applied to Grade 8 and 10.9 fasteners. Metric fastener grading is subject to ISO ruling. Grade 8 does not follow ISO rulings. E.g., there are no standards for surface discontinuities on any inch-standard fastener, but there are for metric. There is more reading at ASTM's (formerly the American Society for Testing and Materials) website than all of us here at CN could consume in a lifetime.


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TennDon
member
*****

Reged: 07/10/11

Re: Pathetic CG-5 latitude adjustment bolts new [Re: cn register 5]
      #5943545 - 06/27/13 06:00 PM

Quote:

What I don't understand is how people manage to break or bend these screws. Don't they notice that the adjustment is getting difficult to move. Do they keep going until something breaks rather than stopping and finding out what is happening?

Chris




I always try to give my CG5 alt/az bolts a helping hand by gently pushing the mount is the direction I want it to go. Haven't had any bolt-bending or breaking off problems. Just my $0.15 worth ( adj. for inflation ).


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SKYGZR
scholastic sledgehammer
*****

Reged: 08/14/09

Loc: Planet Earth, Milky Way Galaxy...
Re: Pathetic CG-5 latitude adjustment bolts new [Re: Cliff Hipsher]
      #5943625 - 06/27/13 06:51 PM

Quote:


You get it very, very close with a Polar scope before you mount the OTA. If the Polar scope is used properly, very little adjustment would be needed. We are talking about fractions of a turn as opposed to cranking on the bolts 8-10 times.




One can also adjust via the tripod legs (best method if scope is already mounted. It's a bit tricky, yet with practice works well.). When close, then fine tune with the adj bolts while giving it a "helping hand" by reaching around to the CW shaft.


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FlyBD5
sage
*****

Reged: 02/12/13

Loc: Boston MA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: FlyBD5]
      #5943626 - 06/27/13 06:52 PM

The mount is fixed. Piece of bolt retrieved from inside the knuckle joint, and it definitely failed as I would have expected a soft bolt to fail under torsion force as I was trying to remove it. Threads are just fine, I replaced the bolts with the knobbed ones from ScopeStuff and they fit fine with a little lubricant.

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Pathetic CG-5 latitude adjustment bolts new [Re: Cliff Hipsher]
      #5945342 - 06/28/13 06:24 PM

Can't help you there. But this post isn't about the LXD75. It's about the CG-5 as the thread title indicates. Does the LXD75 also have spaghetti noodle bolts?

For visual use with a CG5 there's no need to do anything more than align Polaris with the polar scope axial bore hole. You can do that without loading the saddle. Then load the saddle, apply the counterweights and proceed with a 2 star alignment and 3 or 4 calibration stars. You'll be bang on all night and will never bend or break the flimsy little bolts.

With the LXD that requires you to make adjustments loaded, I'd suggest having a buddy help maybe. Someone lifting up lightly on the counteweight shaft while you make the bolts go will really lessen the work being done by the bolts during adjustment.

The Atlas EQ-G is even a bigger joke than the CG5 in this regard. Same flimsy painful bolts but much more head mass to move with them, loaded or not. I replaced those with big all stainless steel bolts with knurled hand knobs from McMaster-Carr, but even with those the buddy system helps during alt-az adjustments, loaded or not.

Regards,

Jim

Edited by jrbarnett (06/28/13 06:50 PM)


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Cliff Hipsher
Pooh-Bah
***

Reged: 12/31/08

Loc: North Chesterfield, VA
Re: Pathetic CG-5 latitude adjustment bolts [Re: jrbarnett]
      #5945501 - 06/28/13 08:06 PM

Quote:

Can't help you there. But this post isn't about the LXD75. It's about the CG-5 as the thread title indicates. Does the LXD75 also have spaghetti noodle bolts?






Yep. The Celestron and Meade GEMs are cousins... When I have an OTA aboard it is impossible to move the mount in ALT by just turning a bolt. If I need to raise the mount (RA axis is too low), I make sure the North bolt is loose, and then I "lift" the optics to take weight off of the South bolt, and then I turn the bolt. Needless to say it takes several iterations to get to where you need to be.

With that being said, next time I get to go out (the weather and seeing/transparency have not been very good lately...), I'm going to try doing a polar before I load the mount and see how it goes....


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