Question about thread sizes

[Starchasm]

Hello, 

I have a question about thread sizes. 

I've looked around the internet the best I can but cannot find any information on what size of threads are inside the skywatcher 350p collapsable goto dobsonian, 14". I am looking for an adapter to screw into the focuser itself as opposed to relying on the set screws for more delicate equipment (almost had an oppsie, so now I want to be prepared for next night it's clear!) but cannot do that until I know what thread size the focuser tube will accept. 

Thanks! 

[CraigT82]

I *think* it’s M54x1. But you’re best to check yourself with a set of calipers ideally but a steel rule would do. Measure across the outside of the threads to get the diameter and then measure along the threads (about 10 of them) to get the pitch. I.e if ten threads are 10mm then it’s a 1mm pitch 

[bosun21]

Yes it's M54 and you can get a Baader clicklock or there's an Astro Essentials compression ring adapter from FLO that will do the job. If going for a clicklock ensure that it's the one for Skywatcher Newtonians as there is another M54 for the Bresser scopes which has an i in the title IE: M54i.

[Starchasm]

Thank you all for the responses, it's greatly appreciated! 

[paulastro]

On 05/09/2024 at 18:20, Starchasm said:

Hello, 

I have a question about thread sizes. 

I've looked around the internet the best I can but cannot find any information on what size of threads are inside the skywatcher 350p collapsable goto dobsonian, 14". I am looking for an adapter to screw into the focuser itself as opposed to relying on the set screws for more delicate equipment (almost had an oppsie, so now I want to be prepared for next night it's clear!) but cannot do that until I know what thread size the focuser tube will accept. 

Thanks! 

This device is very useful for measuring bolts size and pitches.  It comes in different colours and various makes.  I think I paid around £8 some time ago on Amazon, it's had lots of use!

There's also a good video on utube somewhere on how to use it - very useful!

 

[heliumstar]

2 hours ago, paulastro said:

This device is very useful for measuring bolts size and pitches.  It comes in different colours and various makes.  I think I paid around £8 some time ago on Amazon, it's had lots of use!

There's also a good video on utube somewhere on how to use it - very useful!

 

 

Amazing! Thanks for posting this. Didn't know this existed. Ordering now.