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Finally made an R/C Collimation adapter

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#151 nateman_doo

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Posted 03 August 2022 - 09:24 AM

Anodizing the 6" version:

 

y4HPbndl.jpg

2lFvCsdh.jpg?1

4rS0qquh.jpg


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#152 Mert

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Posted 03 August 2022 - 11:01 AM

Looks great :waytogo:

#153 ekallgren

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Posted 03 August 2022 - 11:57 AM

so uh, for anyone that done this - i'm trying to send my cell in to have one of these mounted. i've got the baffle off and the mirror retaining ring off, but i can't get the mirror out. is it just friction fit onto the center of the mirror cell? it really doesn't want to budge. any advice here? (6" RC)

 

rob

Try to turn the mirror while lifting it from the rear cell, that it what freed mine up.


Edited by ekallgren, 03 August 2022 - 11:57 AM.


#154 nateman_doo

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Posted 03 August 2022 - 12:07 PM

Try to turn the mirror while lifting it from the rear cell, that it what freed mine up.

dude, just bang the mirror cell as hard as you can on the concrete floor.  Guarantee the mirror comes right out! 



#155 Mert

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Posted 03 August 2022 - 12:44 PM

I just put it on my lap, mirror facing down and gave it a couple of bumps with my fist until it came out. YMMV :shrug:

Edited by Mert, 03 August 2022 - 12:47 PM.


#156 ekallgren

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Posted 03 August 2022 - 12:47 PM

dude, just bang the mirror cell as hard as you can on the concrete floor.  Guarantee the mirror comes right out! 

Yeah, no, he might want to put it back together.


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#157 pfile

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Posted 03 August 2022 - 01:08 PM

this thing is really in there tight. won't turn much at all and it's kind of difficult to get much leverage on it. anyway i'm going to try the hot/cold approach and see if that works.

 

it makes me wonder if i'll get it back together again... it is that tight.

 

rob



#158 nateman_doo

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Posted 03 August 2022 - 01:35 PM

Try this. Take a bucket and fill a few inches of water and put it in the freezer.  Once its frozen, place the mirror cell over something that you can get to the bottom of it.  Blast the mirror with a hair dryer until it gets hot.  Then place the ice block on the back mirror cell with the mirror facing down.  Place something that the mirror can "fall on" like a few clean folded cotton rags.  Its only an inch or so to drop.  The block of ice will cause the cell itself to shrink and the mirror will heat the glass to expand.  (or just blast the mirror with the heat, and when hot flip it upside down and put the block of ice on it and gently tap the body of the scope back)

 

ALSO, you can simply take out the mirror cell my removing the collimation screws. Then you can get to the back of the mirror.  

 

If you succeed , I would maybe sand down the plastic shim?



#159 pfile

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Posted 03 August 2022 - 02:21 PM

i managed to move the mirror up about 1mm after one cold cycle. very stubborn. i can feel/see it rocking a little as i try to lift it up.

 

still working on it...


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#160 nateman_doo

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Posted 03 August 2022 - 03:58 PM

LONG push screws.  Like a gear puller.  Any M5 screw with a bunch of threads use the PUSH function of the factory collimation screws to pull the factory mirror cell out of the back of the scope while letting the mirror fall out.  Quarter turn each screw at a time.

 

Maybe cut up a few coffee filters to add some padding to the back of the mirror for some padding and distributed force on the mirror.  I think this is the safest option.  Any other input from anyone?


Edited by nateman_doo, 03 August 2022 - 04:03 PM.


#161 pfile

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Posted 03 August 2022 - 05:02 PM

pushing it out from behind worked. for the benefit of others, the reason why it wouldn't come off the spindle is that there are 3 pieces of double-sided tape sticking the mirror to the spindle.

 

rob

 

edit - it was 4 pieces, each about 15mm long. looks like standard double-sided tape.


Edited by pfile, 03 August 2022 - 05:06 PM.

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#162 nateman_doo

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Posted 04 August 2022 - 08:33 AM

Woohoo! I don't think you need to replace the tape when you put the mirror back. I didnt even have any tape on my mirror in the first place. Just dont go crazy wrenching the baffle tube down and distort the optics. Hand tight, slight compression on the O-ring to keep it in place is all that is needed.

#163 Mert

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Posted 04 August 2022 - 09:20 AM

O-ring?
Mine doesn't have any!
Any image of it?

#164 pfile

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Posted 04 August 2022 - 10:04 AM

no o-ring on the 6" either. the plastic shim seems to be firmly attached to the mirror itself. i got the impression it was a standalone part on the larger RCs.

 

rob



#165 nateman_doo

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Posted 04 August 2022 - 10:07 AM

my 8" had a small O-ring on the baffle tube.  like 1/16" of an inch material that makes contact with the mirror. 



#166 nateman_doo

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Posted 04 August 2022 - 10:08 AM

Sulfuric Acid bath:  https://i.imgur.com/OwaQYHZ.mp4



#167 pfile

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Posted 04 August 2022 - 10:09 AM

i will check if it is stuck to the baffle... but i don't think there was anything.



#168 Mert

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Posted 04 August 2022 - 10:56 AM

Just checked on my baffle tube, there is the threaded part that should hold

the mirror to the cell with threads on the other end to thread the baffle tube onto.

There is a small circular indent where the O-ring should be.

Any dimensions of the O-ring welcome!!



#169 nateman_doo

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Posted 04 August 2022 - 11:04 AM

I made my own O-ring with 1/16th rubber O-ring material. 

 

Here   (Not what I used specifically, I got it from McMaster-Carr for actual waterproofing material with special glue)

 

use any form of krazy glue to bond it together.  its not a seal for any type of waterproofing, its just a soft seal to keep the rubber in place. 

 

If you cut the O-ring at a 45° angle with a straight razor, you will have more surface to bond.  CLEAN the material before glue.  Granted its not for a waterproof seal, just more of a bushing so straight Aluminum isn't touching your mirror.  Especially since aluminum will expand and contract and you have a chunk of glass involved. 


Edited by nateman_doo, 04 August 2022 - 11:05 AM.


#170 Mert

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Posted 04 August 2022 - 11:24 AM

Thanks for the info!!

So I need 1/16th thickness for the O-ring, will try and find one

over here.

Better to have an O-ring installed IMHO.

Maybe the former owner dismantled and lost the O-ring?

 

I found an interesting article on internet on dismantling the

primary mirror: https://deepspacepla...8rcpointing.php


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#171 pfile

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Posted 04 August 2022 - 12:59 PM

ah you know what, now that i'm thinking about it, i did find a cut o-ring inside the OTA once. however, i had assumed it had come from somewhere around the secondary. what's weird though is that i'm pretty sure i've never had the baffle off of this one before now, so i don't know how it would have come out. i'll check the retaining ring for a groove.



#172 nateman_doo

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Posted 04 August 2022 - 01:08 PM

ah you know what, now that i'm thinking about it, i did find a cut o-ring inside the OTA once. however, i had assumed it had come from somewhere around the secondary. what's weird though is that i'm pretty sure i've never had the baffle off of this one before now, so i don't know how it would have come out. i'll check the retaining ring for a groove.

Its there.  Just order some O-ring material and some Krazy glue and make one.  Much better to have O-ring bushing as a buffer between the aluminum and mirror itself.  So the mirror sits in a plastic sleeve, and held in place by a compressed O-ring.  it doesnt have to be perfectly waterproofed seal, but you do want a consistent round layer.  if someone wants to measure, you can probably buy the proper O-ring size on McMaster

 

Go nuts:

https://www.mcmaster.com/o-rings/



#173 nateman_doo

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Posted 04 August 2022 - 01:16 PM

Freshly anodized the original one:

1eUx9vSh.jpg



#174 Mert

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Posted 04 August 2022 - 02:42 PM

Depending on the type of aluminum the black anodizing will be black.
Not all aluminum's react the same.
Yours look very good and uniform.

Edited by Mert, 04 August 2022 - 02:48 PM.


#175 nateman_doo

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Posted 04 August 2022 - 02:47 PM

6061 is the type of Aluminum for these adapters.  Don't really need exotic ballistic/aircraft grades of aluminum to hold up 10 lbs at most.  6061 accepts an anodized coating quite well.  




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