# Spotting Scope DIY Repair



## dchan (Jun 29, 2004)

RC stores are your best bet.

If the screw you think is missing is one of those with a guide shoulder, you may be flat out of luck. eBay for a replacement eyepiece may be your best bet.

Those are usually micro metric screws. And often extremely hard to locate.

DC


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## Bob Furman (May 16, 2012)




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## dchan (Jun 29, 2004)

If you can figure out the screw size, (that looks like an SAE thread) 6-32 or 4-40

You may be able to find a brass socket cap screw that may work. You would probably have do some machining.

Or maybe call an optics repair shop and beg them to dig through their screw piles.

DC


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## Bob Furman (May 16, 2012)

Finally got to the point of taking it all apart and noticed that the screw basically fell out and it got trapped behind the inner assembly where the slot is. Finally I figured out that the two pieces that rotate are just snap fitted together via an o-ring. So I managed to separated the two pieces after some good tugs and the screw was free 

Now hopefully it will all go back together ok.


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## dchan (Jun 29, 2004)

Clean the threads real well (solvent like alcohol) and a drop of blue loc tite on the threads. 

Then a very light dab of lithium (white) grease on the sliding parts. wipe the grease almost completely off and then re-assemble. It will make that eyepiece so smooth, you will wish you had done it a long time ago. Don't use oil as it will migrate.


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## dchan (Jun 29, 2004)

and you should have to ask me how I know..:wink:


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## Bob Furman (May 16, 2012)

ok, I give. How do you know?


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## Bob Furman (May 16, 2012)

And Yes, I did manage to get it back together and working. The only hard part to figure out was getting out the inner tube assembly and then the assembly of everything.


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## dchan (Jun 29, 2004)

Sorry that should have read 

"you should *NOT* have to ask me how I know".

and 

Been there done that. On one of my older eyepieces. first assembly only lasted 2 months and the screws backed out again. Also noticed after re-assembly it was rough moving which is what prompted me to take it apart again and that's when I found that the screws had started to back out.. I did the loctite then oiled (heavier "grease") and re-assembled. Felt real smooth but after about 4 months in the hot summer, I noticed a little clouding around the edges. Took it apart to clean the lenses and that's when I noticed that the grease had migrated to the edges of the lenses. Full cleaning of all the lenses and re-assemble, with lithium and no more problems. Lasted 4 years until I replaced the eyepiece with a higher grade astro eyepiece and never looked back.

I suspect higher grade eyepieces (even tasco's) probably have the lenses sealed pretty well so the grease migrating may not be a problem but the one I had was one of those cheap asian knock off made for xyz company clone type scopes. I've since moved on but it was a learning experience.

DC


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