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Lost a screw

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#1 Obi-Wan Kenewbie

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Posted 19 December 2018 - 02:57 AM

Greetings! I somehow manage to lost the main screw in the focuser of my celestron c9.25. Can i found somewhere a new one?

 

 

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  • 5-Focuser-Removal-Step-2.jpg

Edited by Obi-Wan Kenewbie, 19 December 2018 - 02:59 AM.


#2 Dynan

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Posted 19 December 2018 - 03:47 AM

Looks like an M5 (or M4) screw. Should be able to get at any hardware store. Cheap enough to get an M4, 5, and 6 just to avoid a return trip if it's not an M5.


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#3 Obi-Wan Kenewbie

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Posted 19 December 2018 - 08:32 AM

Thank you for your time! All the M5,M4 e.t.c have standard dimensions or the M stands just for the thread?



#4 jhayes_tucson

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Posted 19 December 2018 - 09:36 AM

'M' is for metric.

 

John


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#5 Benach

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Posted 19 December 2018 - 11:20 AM

Obi-Wan Kenewbie: M stands for metric, the number behind it is the out diameter of the thread. So M4=Metric screw with 4mm (about 0.157"). Metric Fine screws exist but are rarily available from the normal hardware stores around.


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#6 Obi-Wan Kenewbie

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Posted 20 December 2018 - 02:08 AM

Thank you all guys!



#7 Benach

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Posted 20 December 2018 - 03:16 AM

Dynan: they do not. Pitch can be found in tables such as this one. Spoed is the Dutch word for pitch. But note that unless you are a mechanical engineer, metric fine threads are pink elephants.



#8 Ptkacik

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Posted 23 December 2018 - 10:09 AM

I thought metric fine threads were rare but was getting a Mercedes car part in a salvage yard and picked up a handful of bolts on the ground. To my surprise, they were all varied. Three of the M10's had different pitches. I even had a handful of M7's which I've never seen before.

If you can't get a good match, you can always get a bolt at McMaster-Carr as they have everything, e.g., M8-1.0 and M8-1.25, 8mm OD by 1.25mm pitch. They also have (nearly) every material and strength and bolt head and coating.

Also be wary of metric M5 and SAE sized 10-32. These are so close together one nut will fit both screws but not the other way around.

Did I mention I love fasteners? Ha!
Peter
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#9 photojimc

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Posted 23 December 2018 - 11:33 AM

Ace hardware has lots of screws and bolts and all sorts of stuff,  my local store has an isle filled with way too many odds and ends all marked nicely in drawers, there are knobs  washers and most anything I never knew existed 


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