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tube for 6'' refractor

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#1 dron2015

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Posted 15 January 2020 - 09:07 PM

Hi Fellows!

 

I am very much happy with my lens, but not exactly happy with the scope tube. it is a kind of older one w/ focuser flange glued to it... it is made of some composite - perhaps fiber glass - so slower to cool down and still not sure how it will distribute warmth from dew heat straps which I am going to add... Recently I changed focuser - and it is a bit clumsy now.

 

How easy difficult is it to make your own tube? what does it take?

 

I know that Parallax instruments can supply Al tubes. perhaps here are more vendors...

How to you make your baffling systems?

How you paint (coat) your scope?

 

and of course the main question - how to attach the lens (6 screw system) to the tube? How to make this part?

 

Of course, buying new tube is always an option, neither cheap not fast but it is here. However the  scope currently works somehow even in this configuration, and trying to make with your own hands, I believe, IS the part of the fun of this hobby!

 

Cheers,

Andrey

 

UPD: this is NOT my current scope :( this is I would love to make one day! :)

Attached Thumbnails

  • scope.jpg

Edited by dron2015, 16 January 2020 - 04:50 PM.


#2 GShaffer

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Posted 15 January 2020 - 10:46 PM

I would check out hastings irrigation before buying. Thats where I got my 9" tubing for my 8" f/16 build. They are the source parallax gets the tubing from and has drop shipped to you after marking it up......

 

As for baffles, lots of options depending on the equipment you have to work with.....I used 1/16" aluminum sheet and carbon fiber arrow shafts to make knife edge baffles with removable cage with for my build. But plastic, wood, fiberglass are all viable options etc Painted with the flattest black paint I could find.....

 

I bought my lens with a push/pull cell already setup.....Did have to machine it on the lathe to fit the tube. I am fortunate enough to have had access to a well setup machine shop with multiple lathes, mills etc and all the tooling one could ever need along with an observing buddy who is a master machinist.

 

As for painting the scope, powder coating is the 1st choice for durability, automotive paint has been used a lot as well.

 

Just about every question you can think of, the answer can be found in this build topic for my scope as well as some you wont think of LOL.....You might get some ideas at least. Best put some coffee on it you plan to check it all out though, close to 600 posts with LOTS of pictures and machinist's porn.....


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#3 mconnelley

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Posted 16 January 2020 - 02:32 AM

Hello:
 

   The last time I made a refractor, I needed a 5.5" ID tube and found one that was meant to be the inlet for a turbo on a truck.  With the tube in hand, I needed to adapt the lens cell to the new tube.  As mentioned above, having a lathe is a big help here.   I turned the cell until it was a snug slip fit and just pushed it into the end of the tube.  Depending on your lens cell and tube, you may need to machine yourself a spacer ring.

 

   Back when I didn't have access to such tools, I made a jig to make a ring out of plywood on my drill press.  I put threaded inserts into the plywood for the push/pull lens cell screws, and to screw the ring to the tube.  

  

   For the baffles, I made a cage with threaded rod (from Home Depot) and disks cut from sheet metal (I used a rotary table on a mill, but you don't need to be that fancy).  Painting the inside of the tube is important, and I used black paint that I brushed on.  You may need to screw the paint brush to the end of a broom stuck handle (perpendicular to the handle) to reach into the tube.  

Cheers

Mike


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#4 Jeff B

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Posted 16 January 2020 - 10:27 AM

Here is my latest thread:

 

https://www.cloudyni...8-f9-ota-build/

 

And an older one centered around a 6" F10 Jaegers lens:

 

https://www.cloudyni...d-home-cooking/

 

And some pictures I did for a 6" F10 Istar objective.

 

Hastings is a great company to work with and they are fasr but be prepared to spend as much money, or more, on shipping that the price of the tube and order it about a foot longer than you need so if you need to, you can cut off any dented ends.

 

I love powder coating as it is soooo durable and now comes in many colors plus I've found it to be a bit cheaper than having an auto body shop do it, at least around here anyway.

 

Jeff

 

 

Attached Thumbnails

  • Objective A.jpg
  • Countercell D2.jpg
  • Baffles.jpg
  • Finished D.jpg
  • Finished A.jpg

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#5 ed_turco

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Posted 16 January 2020 - 11:15 AM

Hi Fellows!

 

I am very much happy with my lens, but not exactly happy with the scope tube. it is a kind of older one w/ focuser flange glued to it... it is made of some composite - perhaps fiber glass - so slower to cool down and still not sure how it will distribute warmth from dew heat straps which I am going to add... Recently I changed focuser - and it is a bit clumsy now.

 

How easy difficult is it to make your own tube? what does it take?

 

I know that Parallax instruments can supply Al tubes. perhaps here are more vendors...

How to you make your baffling systems?

How you paint (coat) your scope?

 

and of course the main question - how to attach the lens (6 screw system) to the tube? How to make this part?

Now maybe

Of course, buying new tube is always an option, neither cheap not fast but it is here. However the  scope currently works somehow even in this configuration, and trying to make with your own hands, I believe, IS the part of the fun of this hobby!

 

Cheers,

Andrey

I'm a bit puzzled with the picture attached to your post.  It shows a lovely setup and not a composite material.   Now there maybe is a finish that mimics metal that I haven't heard of (It does happen).  If the actual tube is composite, it could conceivably be made of Bakelite, an old-time material that in my opinion is one of the best materials around.  If this is the case, don't throw it away, sell it.

 

You may be pleasantly surprised.
 



#6 dron2015

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Posted 16 January 2020 - 02:42 PM

Fellows,

 

thanks much for your comments and links! It is very helpful. One cup of coffee is not going to be enough - going to the store to grab some beer so I can read all of that! :)

 

On the photo - it is not my scope, unfortunately. Yes, it looks very fancy!

 

Best,

Andrey


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#7 GShaffer

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Posted 16 January 2020 - 02:55 PM

I'm a bit puzzled with the picture attached to your post.  It shows a lovely setup and not a composite material.   Now there maybe is a finish that mimics metal that I haven't heard of (It does happen).  If the actual tube is composite, it could conceivably be made of Bakelite, an old-time material that in my opinion is one of the best materials around.  If this is the case, don't throw it away, sell it.

 

You may be pleasantly surprised.
 

 

99.9999% positive that is a pic of one the custom OTA's built by Mark of Moonraker over in England.....pretty sure he posted it for dramatic effect :) Usually we remove pics that are obviously someone else's or dont include a permission to use statement. Though in this case I am pretty sure Mark doesnt mind the pic being used.



#8 jessebear

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Posted 16 January 2020 - 04:06 PM

I looked into Hastings for a 60mm refractor build, but was able to find the tube from a speed shop on eBay for a better price given that it was such a small piece. Baffles were 3D printed and pressed into the tube with adhesive, and then the interior was shot with flat black. It worked well but they are definitely not easily removable. I've made push/pull lens cells on a 3D printer as well but I would definitely suggest a more durable and less temperature-sensitive material for the cell itself.

#9 dron2015

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Posted 16 January 2020 - 04:49 PM

99.9999% positive that is a pic of one the custom OTA's built by Mark of Moonraker over in England.....pretty sure he posted it for dramatic effect smile.gif Usually we remove pics that are obviously someone else's or dont include a permission to use statement. Though in this case I am pretty sure Mark doesnt mind the pic being used.

GShaffer, you are absolutely right!

 

Recently I found his web over the internet and  stared at the tubes for a long time! beautiful!

 

My apologies for the confusion - it is NOT my current scope. If it would be my current scope the things would be  be easy breazy - if focuser flunge is gluedI could just cut the tube and make new thread for the new focuser.  My scope has "composite" tube  o - so even if I cut it - no thread is possible there...

 

I just ended my text with the phrase that doing something by yourself is a part of the fun at this hobby and though that it might be a good idea to attach some beautiful picture there...

 

Best,

Andrey



#10 Bob4BVM

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Posted 17 January 2020 - 12:25 AM

Here is my 6"F5 build, which has been improved over the past few years as reflected in pic below, but basic OTA is same.

Link below to original build may give you a few ideas for tube, mount, cell, etc.

 

 

 https://www.cloudyni...6-f5-rft-build/

 

CS

Bob

 

NikonZooms,B+L BVer.jpg


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