10 replies to this topic

[Lunar Lady]

I am refurbishing a Celestron C8 that has the finder attachment screws missing. I want to find replacements, but do not know the official designations of size, type, and thread. I cannot find any online sources for these screws either.  Does anyone here have suggestions?

[Eye stein]

Here is what I do in situations like that.

I measure the  width of the holes ( in mm )  as a start, then go to local hardware store where they usually have a board set up with various screws of both metric and inch screws . Once you get close 

on the size , pick up one or two of what you think are close and bring them back to test them. If you can bring the finder with you so much the better. 

PS I usually go to a Lowe's or Home depot ..they are more likely to be Metric----.best of luck

JL

[sevenofnine]

I do similar to Eye stein but if there is a similar screw that you can safely back out of the mount then you can take it to ACE Hardware. The "Helpful Hardware Man" will size it for you. They have tons of replacement screws. 

[whizbang]

Any hardware store can help you out.  Celestron used American threads back in the day, either 6-32 or 8-32.  I don't recall.  The never tubes might be metric. 

 

Either take the tube in as suggested, or just go buy a 6-32, a 8-32, M3.5 and M4 screws and see which one fits.  Then figure out how long or deep yoiu need to go, and a set.

[KuiperBeltKing]

If the OP is trying to do a proper refurbishment, then she would want to find a set that is the correct color and screw head type. It would be impossible to find those in a hardware store. The store could help to point her in the right direction by identifying the size and threads of one that she has.

 

It would be helpful to know the exact iteration of the C8 in question. Celestron made them over many years. Someone may have a damaged match just gathering dust or pieces that they would be willing to let go. 

[Lunar Lady]

That is precisely the situation.  I discovered that a set of screws of various thread types and sizes is available from Scope Stuff. That is extremely helpful for starters.  I wish I knew exactly how to determine which iteration is the exact one for this C8.  If anyone has a good detective tactic for that, I would love to get started on that phase of the project.  Thanks to everyone for all the help so far.

[Echolight]

I think it's a 6-32. Just make sure they're not too long. Don't want them contacting the mirror.

 

I'm pretty sure the finder base uses phillips flat head. But can't remember if stainless or black.

Edited by Echolight, 13 May 2024 - 12:01 AM.

[ToeMoss]

If the OP is trying to do a proper refurbishment, then she would want to find a set that is the correct color and screw head type. It would be impossible to find those in a hardware store. The store could help to point her in the right direction by identifying the size and threads of one that she has.

 

It would be helpful to know the exact iteration of the C8 in question. Celestron made them over many years. Someone may have a damaged match just gathering dust or pieces that they would be willing to let go. 

 

You've not been to my local ACE hardware store.  They have had every fastener I've ever looked for there!

[Lunar Lady]

Despite a whole list of impediments, I finally did go to my local ACE hardware store. They had the screws I needed and I bought six of them so that I have two more than I needed. Someday, I my have to replace one that landed in the grass, or some other freak occurrence.  Who knows?

Thank you for the most useful advice!  It was so much easier than I had imagined when I started this project. I am delighted with the outcome, and the scope is looking much better. Thanks for the great tip!

[Oldfracguy]

Glad you found the right screws  .  Last year I bought a Vixen-style finder scope mounting shoe to put on a C8, and was suprised to learn that those tapped holes in the body of the C8 were not Metric after all.  

 

 

 

 

[Lunar Lady]

It is true! I was also surprised to find that out when I began my restoration project. All the screws on my C8 are SAE.