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Cheap AltAz Mount


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My scope has one of these fantastic mounts. It makes pointing very difficult as the "fine adjustment" threads are so loose everything wobbles around in the slightest breeze. The pivot is also just a fork screwed onto a bolt without bearings so if you unscrew it enough to rotate you then get more wobble....

Is there anything you guys would do to make this more useable? Or should I just scrap it and make a dobsonian style AltAz mount?

post-39279-0-96388600-1412361073_thumb.j

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That mount could have vibration problems, if you want to go down the DIY route, with cast iron tubing, then use a basic tripod design for the legs, it will be much more stable, although may be on the heavy side to cart around :)

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The design itself is not too bad from a vibration point of view - it is essentially the same layout as the Tal mounts which are excellent.

That said, 2" may be a little light and I think glowjet is right - you would be better off making a tripod. However, if you take yourself off down to a decent plumber's merchant and use a length of cast iron sewer pipe (110mm iirc), you could be on to a winner.

Neither design is going to fall into the "lightweight" category, however!

Edited by jamespels
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Well I needed a better mount but do not have any money to spare so I spend $11 at the home center and came up with this. Its only 3/4" pipe but the telescope is also only 3lbs. I filled the tripod legs with paving sand and that made the tripod from 1lb to 8lbs. I lapped the threads on the polar and dec axis an extra 4 turns so they move very easily.

Hopefully clear skies before bed tonight and I can give it a try!

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Ah, didn't realise you already had a tripod! Sometimes it is very hard to beat a good bit of basic engineering and this is a great example. As Dave says, excellent reuse of materials.

Btw, do you find the OTA is stable on the plank? If not, a strip of wood down either side should keep it lined up.

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That looks such a simple design to be able to get both direction movements. What stops the turning joints from popping out?

Love the counter weight, simple but functional.

I put valve grinding compound on the joints and screwed/unscrewed them until I was able to get 3+ more rotations on them. The joint is a little loose but with weight and grease afterwards it is very stable. Its easy to tell if you are flipping in the same direction to much as the joint gets sloppy.

It is immensely easy to point and I tested tracking on a few random stars and it works perfectly for viewing. No wobble from the breeze in the slightest which was my main reason for this endeavor.

Ah, didn't realise you already had a tripod! Sometimes it is very hard to beat a good bit of basic engineering and this is a great example. As Dave says, excellent reuse of materials.

Btw, do you find the OTA is stable on the plank? If not, a strip of wood down either side should keep it lined up.

It is stable when snugged down as the system rotates so freely BUT I see you need to rotate the OTA so the eyepiece is more convenient as you track. I am going to bandsaw up a pair of curves that will clamp the tube in place and parallel but be loose enough to allow rotation.

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  • 1 month later...

Looking at the pipe-mounts, it reminded me of  a copy of an american book I used to have. I think it was dated from about 1985, (though I cannot remember the name of it). :cussing:  It included plans and instructions on how to build a pipe-mount, (and a 'simple' newtonian with a floorboard or other length of a hardwood timber). Amatuer astronomers are very inventive when resources and financial funds are limited. :book1:

Edited by Philip R
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  • 6 years later...
On 07/10/2014 at 04:41, uminded said:

I put valve grinding compound on the joints and screwed/unscrewed them until I was able to get 3+ more rotations on them. The joint is a little loose but with weight and grease afterwards it is very stable. Its easy to tell if you are flipping in the same direction to much as the joint gets sloppy.

It is immensely easy to point and I tested tracking on a few random stars and it works perfectly for viewing. No wobble from the breeze in the slightest which was my main reason for this endeavor.

It is stable when snugged down as the system rotates so freely BUT I see you need to rotate the OTA so the eyepiece is more convenient as you track. I am going to bandsaw up a pair of curves that will clamp the tube in place and parallel but be loose enough to allow rotation.

Hi all I'm making a gem pipe mount,I've got a 4" sq pillar with 20" legs it's about 4 feet high at the moment if needed I will cut it down to acheive a comfortable eyepiece height.I've weighed it and it's real heavy just over 42lb without counterweights! and I've not even built the 6" scope yet got a goood deal on a David Hinds mirror and matching secondary for £25.

I'm lapping the threads with cutting paste,what I need to know is when do you stop as if I unwind too much the threads gently rock but with the weight of the tube on top etc would surely keep it stable?  or do I need to continue lapping the threads? I'm using 1 1/2" pipe any advice would be appreciated looking forward to making the OTA from Richard Berry's book as reference and that should add another 18lbs !!

Clear skies.

Ash.

Pipe gem mount.jpg

Edited by MrZuiko
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