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That sinking feeling - Again


Teslar
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Well my run of problems or (as they say at my work) opportunities, continue. Finally a clear night in East Lothian and I sat patiently for semi darkness. Yep there is alway a glow from SOL on the horizon which creeps around until it pops up again. Well finally Polaris was twinkling along with quite a few other and it was looking promising so I popped out to the obsy as you do and was looking forward to experiencing the ease it will provide. I decided to use Alignmaster for polar alignment so set up on The first star and slews to the second the adjustment stage showed I was only a few minutes out on both access so I quickly made the adjustments and like magic I was aligned (finally) or so I thought. As I set up on my chosen target I was surprised to see star trails four minute subs, I was expecting better as I've had better just on the tripod. So I revisited Alignmaster and chose another two stars to re run the routine. Once again I adjusted the alt and it was almost spot on but the Az was a mile out. I started to adjust this when........something gave way and the star jumped out of view. On closer inspection there was debris on the adjusting screw and that's when my heart sank. I just packed up and went to bed.

This morning I went out and stripped it all down.

yra3yju9.jpg

The Gunnar mod was still in place it hadn't moved but sadly the Az bolts was looking to be the problem.

zata4yze.jpg

When I removed it half of the threads came out with the screw. So as I feared the tapped hole in the mount was stripped. I'm guessing that the TS10" even though its carbon when fully loaded and within 15kg counterbalance is just too much weight for the NEQ6 or at least my one which at one time had a steel Quattro 10" so maybe the damage was done then or maybe just a combination of wear and tear and bad luck. But whatever it looks like a helicoil job is required

When I'm finished all the weak point of these mounts will have been cured. I'm sure a few of you have been here before me......,,,

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helicoiled my mount Tom, as my alt hole was looking worn and oval in shape, bought a kit from e bay for less than £9 which had plenty of coils in it and the tap, real easy to do and certainly firmed the threads.


i can send you a helicoil if you have the tap already.


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Bloody hell Tom you are not having a lot of luck up there are you.


 


An M10 Helicoil requires a drill of 10.5mm and special tap to suit the Helicoil.


My advice would be to tap out the damaged thread hole with your M12 tap and use a bolt.


Edited by Graham
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Yep it never rains but it pours as they say. There is a local precision engineers shop I recently found so I'll try there in the morning

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Well the engineer shop doesn't do helicoil it seems. But did think it was the best solution in that it allows me to keep the astro development screws. So I've gone for the EBay kit Rob suggested. Just a little worried at the screw depth in the mount as the casting looks only about 12 mm thick in that area. If the helicoil is longer I guess I might have to reduce it in length.

Rob what did you find out when you did yours?

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here`s a picture of the kit Tom,


you get everything you need to do a proper job.


basically the ali housing is fairly thin and the helicoil is longer than the housing by about 6 or 7 mm but as you re tap the mount with a bigger hole the helicoil then screws into it and is very stable, very easy to do, 10 minute job, if you need a coil let me know.


 


helicoil-kit_zpsfe45aedb.jpg


Edited by red dwalf
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Thanks Rob. I take it you left it 6mm proud on the inside. Given out latitude I guess there is plenty clearance inside :)

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