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Replacing a Polarscope Reticle

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#1 fishonkevin

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Posted 14 August 2012 - 08:52 AM

Hi Folks,
I picked up an updated reticle for the polarscope of my Losmandy GM-8 and I am having trouble removing the old one. Have any of you replaced your reticle? I can't seem to get the retaining ring to unthread. Do you need a special tool?

Thanks, Kevin

#2 Phil Sherman

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Posted 16 August 2012 - 06:34 AM

I've never seen a Losmandy polarscope but do know that most retaining rings have two slots in them for a tool called a "spanner wrench" It's two small screwdrivers mounted on a bar that allows you to adjust the distance between them to fit different sized rings. Set it to fit the slots in the rings and you can just unscrew the ring. I've also seen some rings that have small holes instead of slots. THe holes serve the same purpose and a good spanner wrench kit will include a number of tips to fit different types of rings.

Phil

#3 DaveJ

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Posted 16 August 2012 - 07:29 AM

I've never seen a Losmandy polarscope but do know that most retaining rings have two slots in them for a tool called a "spanner wrench" It's two small screwdrivers mounted on a bar that allows you to adjust the distance between them to fit different sized rings. Set it to fit the slots in the rings and you can just unscrew the ring. I've also seen some rings that have small holes instead of slots. THe holes serve the same purpose and a good spanner wrench kit will include a number of tips to fit different types of rings.


Here's the one I purchased. Rather pricy, but believe me, it's a life-time investment. Since getting it, I've used it for a number of projects with perfect results.

#4 fishonkevin

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Posted 16 August 2012 - 07:39 AM

Thanks Phil and Dave. I figured it would take a special tool. But now I know what the tool is called, and can find one locally.

#5 Startraffic

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Posted 18 August 2012 - 12:06 PM

Kevin,
After you get the retaining ring out, there are also 3 centering screws that you'll need to adjust to center the reticule in the PA. Be careful when adjusting the reticule. Too tight & you'll hear a tiny little "crack" & you'll need another reticule. DAMHIKT I put a tiny dab of silicon on each of the screws & let it set up overnight. You don't need a lot, just enough to cushion the reticule from the screws. HTH

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#6 fishonkevin

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Posted 21 August 2012 - 11:08 AM

Thanks Startraffic, I'll keep that tip in mind. Right now I'm still working on getting the spanner wrench.

#7 Startraffic

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Posted 10 September 2012 - 02:03 PM

Kevin,
Try this http://www.harborfre...ner-91550.html. Worked for me.

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#8 SergeC

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Posted 10 September 2012 - 03:38 PM

A small harwood block with two nails/brads driven in the right distance apart can serve as a spanner in a pinch...

#9 Geo.

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Posted 11 September 2012 - 03:57 PM

On Flea bay they start at $16. Search "Lens Spanner Wrench"






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