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Secondary Mirror Milk Jug Washers

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31 replies to this topic

#26 SteveG

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Posted 23 February 2015 - 04:00 PM

 

 

The milk jug washer is not only meant to protect the secondary mirror stalk from the adjustment screws otherwise a metallic washer would have been good enough.

The main benefit of the milk jug washer is to provide little elasticity to make fine adjustments -- something a hard object like a metallic washer or even a hard plastic will not provide. That is why I suggest using 1 or 2 washers to provide different levels of elasticity.

The elasticity of the milk jug washer seems about to be the right amount.

In addition, it is easy to install. If the scope owner does not want to remove the secondary mirror then he/she can make a radial cut and slide the washer in as I have shown in post # 8 in this thread.

Jason

Yes, this is it and it works very well. I used black Kydex from Scopestuff, and have 2 of them stacked between the seconday holder and the screws.

 

 

 

 

Hi Steve, I did not know Scopestuff carries them. Did you mean Opticsmart?

http://www.cloudynig...asher-question/

Jason

 

Here's a link:

http://www.scopestuff.com/ss_kydx.htm



#27 Jason D

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Posted 24 February 2015 - 02:01 AM

Here's a pic of my old ones. I've replaced them with black Kydex (similar material).

 

Just curious, how does the Kydex material compares to your homemade milk jug washers?

 

Jason



#28 SteveG

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Posted 24 February 2015 - 01:47 PM

 

Here's a pic of my old ones. I've replaced them with black Kydex (similar material).

 

Just curious, how does the Kydex material compares to your homemade milk jug washers?

 

Jason

 

Exactly the same. I just wanted them to be black.



#29 WyattDavis

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Posted 18 July 2015 - 07:39 AM

Along the lines of the milk jug modification, I had substantial frustration with the lack of accuracy/stability with the metal-to-metal contact between the collimation screws on my XT10 and the back side of the secondary housing. Especially when trying to use an autocollimator, I couldn't get the level of accuracy and stability for good secondary alignment. I put in Bob's Knobs and then put vinyl screw-end caps over the screw ends. It seems to have the same effect and makes achieving a stable secondary alignment much easier.

 

After more experimentation, I am finding that the milk jug solution is indeed better than the vinyl screw caps that I tried. The milk jug plastic is harder than the screw caps and provides a more stable surface to work with. +1 for Jason's original solution.



#30 Billytk

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Posted 18 July 2015 - 08:17 AM

I got my washers for my XT12G from Opticsmart. It makes it SO much easier to get the secondary adjusted!



#31 Pinbout

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Posted 18 July 2015 - 08:24 AM

 

Here's a pic of my old ones. I've replaced them with black Kydex (similar material).

 

Just curious, how does the Kydex material compares to your homemade milk jug washers?

 

Jason

 

 

I contact cement kydex to the back of my stalk so the nylon screws don't dig into the maple.

 

having the nylon screws is the best.

 

med_gallery_106859_3508_141619.jpg



#32 howard929

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Posted 18 July 2015 - 08:50 AM

 

Along the lines of the milk jug modification, I had substantial frustration with the lack of accuracy/stability with the metal-to-metal contact between the collimation screws on my XT10 and the back side of the secondary housing. Especially when trying to use an autocollimator, I couldn't get the level of accuracy and stability for good secondary alignment. I put in Bob's Knobs and then put vinyl screw-end caps over the screw ends. It seems to have the same effect and makes achieving a stable secondary alignment much easier.

 

After more experimentation, I am finding that the milk jug solution is indeed better than the vinyl screw caps that I tried. The milk jug plastic is harder than the screw caps and provides a more stable surface to work with. +1 for Jason's original solution.

 

 

after realizing i replied here earlier, no real need to say my piece again.


Edited by howard929, 19 July 2015 - 09:35 AM.



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