Ebony Star alternatives

[adarshajoisa]

Hi SGL,

It's been a while since I've posted here. A friend and I are modifying my 16" lightbridge to an ultra compact design. Our plan is to go observing to the Indian Astronomical Observatory in the Himalayas next month, for a week. To make the scope portable, we're redesigning the primary cage and the rocker box. For the altitude bearing, we're unable to find any alternatives for Ebony Star (50) laminate. From what I've heard, it's currently out of production. Here in India, it's close to impossible to get laminates in small quantities. They only sell huge sheets of it, which we won't need. Do you know of any alternates for Ebony Star? Are there any retailers who sell small quantities for ATM? I have a friend who'll be travelling back from the US at the end of this month, so if I can order something there, he'd be able to get it back to India. We're quite short on time, so we don't have the luxury of experimenting with locally available laminates to achieve ideal stiction with teflon. Any help would be greatly appreciated!

 

Thanks,

Adarsha.

[mapstar]

Hello Adarsha

If you can get hold of any of the Formica branded laminate in India then the exact match is 

FORMICA pattern range stardust HGP F1782 CW (quarry effect)

Or here on the Formica website

Ebony star alternative

It comes in 3050mm x 1300mm sheets usually and does cost a fair bit but there maybe some locally. I have some although the postage costs from the UK to India may be expensive? I'm guessing the area needed for the bearings will be an 25mm wide at the most and 400-500mm long.

Regards

Damian

[adarshajoisa]

Damian,

Thanks a lot for the suggestion! I'll try to find if there are any dealers locally who sell this particular model of Formica. I'll keep this thread updated with our progress  

[Astrobits]

Find a Kitchen worktop manufacturer. They will have offcuts, probably for free.

Nigel

[Sanath Kumar]

Hi all,

This is the scope adarsha mentioned , i had hammered some teflon with nails, but that was causing problems so i removed them, the motion in alt is much smoother now, i am considering a high density car roof carpet material on the lower side, and locally available matt finish laminate on the alt bearings. has anyone tried this ? , also what about teflon on teflon, i have a huge sheet os 1/8" virgin teflon and will be able to readily use it.

 

[saac]

 Sanath, Adarsha, firstly that is a lovely looking setup you have there. What type of wood have you used on the mirror and rocker box, it has a beautiful grain running through it.  As far as Ebony Star is concerned what you are looking for is any laminate which has some form of raised or slightly bumpy pattern to it. The idea is that the raised pattern results in a smaller contact area than would otherwise be the case with a completely flat laminate and of course the lower contact area reduces the overall friction felt between the bearing surfaces.  I would have a look around your local kitchen/diy suppliers and see what is available. At the end of the day if you can't find something with a raised pattern then go with the any flat laminate if that is what is available.  Teflon on teflon would work as well in principal but laminate has been used traditionally as it is manufactured to good conformity as a flat uniform surface available in long strips.

I'm part way through a dobsonian build and I have a spare roll of laminate 1500mm x 42mm by 2mm thick.  It has a flat surface rather than raised, I was planning to use it but then I found a raised patterned laminate in the store so I used that instead. It is easily cut with a sharp craft/diy knife into the necessary strip lengths.  If you think it would be of any use to you then let me know, I'm happy to pass it on at no cost. I can post a picture if needed.

An opportunity to do astronomy in the foothills of the Himalayas, wow that will be some experience. You must come back and tell us all what it was like; the quality of the sky in particular. Good luck.

Jim

[Sanath Kumar]

6 minutes ago, saac said:

 Sanath, Adarsha, firstly that is a lovely looking setup you have there. What type of wood have you used on the mirror and rocker box, it has a beautiful grain running through it.  As far as Ebony Star is concerned what you are looking for is any laminate which has some form of raised or slightly bumpy pattern to it. The idea is that the raised pattern results in a smaller contact area than would otherwise be the case with a completely flat laminate and of course the lower contact area reduces the overall friction felt between the bearing surfaces.  I would have a look around your local kitchen/diy suppliers and see what is available. At the end of the day if you can't find something with a raised pattern then go with the any flat laminate if that is what is available.  Teflon on teflon would work as well in principal but laminate has been used traditionally as it is manufactured to good conformity as a flat uniform surface available in long strips.

I'm part way through a dobsonian build and I have a spare roll of laminate 1500mm x 42mm by 2mm thick.  It has a flat surface rather than raised, I was planning to use it but then I found a raised patterned laminate in the store so I used that instead. It is easily cut with a sharp craft/diy knife into the necessary strip lengths.  If you think it would be of any use to you then let me know, I'm happy to pass it on at no cost. I can post a picture if needed.

An opportunity to do astronomy in the foothills of the Himalayas, wow that will be some experience. You must come back and tell us all what it was like; the quality of the sky in particular. Good luck.

Jim

Hi Jim, 

i dont remember the name of the wood , but its actually a sheet of 4mm veneer , thankfully in Bangalore we can get any veneer we want, i will find out the name of the wood and get back asap, the place adarsha is referring to is Hanle and is one of the sites which was selected for the construction of the 30m telescope or TMT , currently the site hosts a 2.3m remotely controlled optical telescope and a gamma ray array, the seeing is considered one of the best in the world and we are hoping to do some good DSO hunting there, getting friction right is the last and the only problem on our list now. Thanks for your advice on the raised laminate, i will hunt for some nearby and hopefully will be able to get some .

[saac]

Sanath, I've just checked out Hanle and the national observatory on Google Earth. Again wow, what a fantastic looking site, and at 4,500 m the 16 inch dob should really bring out the DSOs.  I'm envious, you have a great incentive to get the scope modified. Good luck.  

Jim

[Sanath Kumar]

Hey jim,

             me and a few others are going this time, but we intend to invite visual observers from around the world to Hanle in the near future and organize a one week observing session, it will happen soon enough, and i am looking forward to meeting all the members of SGL and also DSF .

23 minutes ago, saac said:

Sanath, I've just checked out Hanle and the national observatory on Google Earth. Again wow, what a fantastic looking site, and at 4,500 m the 16 inch dob should really bring out the DSOs.  I'm envious, you have a great incentive to get the scope modified. Good luck.  

Jim

the mod got over (almost) in exactly a month, we had to do it as carrying a huge lightbridge is not a good idea.

[Sanath Kumar]

here are some more pics :

http://imgur.com/a/pvjiU

comments and advice welcome 
 

[mapstar]

The wood veneer looks to be Zebrano to me. Just a guess 

[Sanath Kumar]

Hi damian, 

               yes, it is zebra wood , thank you

[Sanath Kumar]

Hi all,

this link has all the pics and the videos of the mod 

 

https://drive.google.com/drive/folders/0B1Q9Qcz4nCaXRTRwTW9fbllESzQ?usp=sharing

[saac]

Sanath did you have any luck getting hold of the bearing material? I'm getting to teh stage to do my bearing this weekend, bit nervous about gluing it up.

Jim

 

[brantuk]

Hi Adarsha - I don't know where your buddy in the States is, but Dennis Steele in CA is a professional dob builder/modifier and I'm sure he'd be able to help you out: http://www.dobstuff.com/contactus.htm

Hth

[adarshajoisa]

On 8/30/2017 at 03:21, saac said:

Sanath did you have any luck getting hold of the bearing material? I'm getting to teh stage to do my bearing this weekend, bit nervous about gluing it up.

Jim

 

Jim,

We used the car roof carpet material instead of teflon, and the stiction has improved a lot, and the scope is usable now. I'm planning on sticking to it for the time being, and maybe try for ebony star alternatives in the future when I have free time and budget.

[adarshajoisa]

On 8/30/2017 at 04:43, brantuk said:

Hi Adarsha - I don't know where your buddy in the States is, but Dennis Steele in CA is a professional dob builder/modifier and I'm sure he'd be able to help you out: http://www.dobstuff.com/contactus.htm

Hth

Thank you for the reference, Brantuk! I'll definitely get in touch with him.

[saac]

10 hours ago, adarshajoisa said:

Jim,

We used the car roof carpet material instead of teflon, and the stiction has improved a lot, and the scope is usable now. I'm planning on sticking to it for the time being, and maybe try for ebony star alternatives in the future when I have free time and budget.

Sounds like an excellent bit of innovation Adarsha, good luck with it.

Jim