Revelation 12" Dob - Primary Collimation Screw sizes

[rookieoftheyear]

Hello all.

I have a Revelation 12" Dobsonian and trying to replace the primary collimating thumbscrews for some Bobs Knobs.

Can anyone advise the size of the screws?

I have tried the Meade Lightbridge 12" primary Bobs Knobs and the thread is too thick.

Thanks

[emadmoussa]

I don't know about the Revelation, but if they're the same as the SkyWatcher, then you can use these:

https://www.ebay.co.uk/itm/M4-x-30mm-Male-Thread-Plastic-Knurled-Head-Clamping-Knob-Jig-Black-10pcs/362278629231?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 

[rookieoftheyear]

Thanks for the reply but I was hoping someone who owns/owned this 'scope could tell me the exact thread size I need.  Or, the part number from Bobs Knobs.

Allegedly the mirror cell is the same as the Meade Lightbridge 12", but as above the Meade colli screws are a bit too big.

[Rob]

You could ping an email to Telescope House?. I'm sure they will confirm this. Rob

[rookieoftheyear]

Thanks, have done, and got a very prompt reply saying they think it's an M6 or M7.  So the mystery is still somewhat unsolved

[John]

I'm surprised that the Meade 12" ones don't fit. My understanding is that the Meade Lightbridge and the Revelation dobs are both mde by GSO and share common optics and optical cell designs.

[Mark at Beaufort]

I have a 12" Revelation Dob and bought these - https://www.rothervalleyoptics.co.uk/bobs-knobs-celestron-starhopper-12-primary-springs.html

 

[rookieoftheyear]

13 hours ago, John said:

I'm surprised that the Meade 12" ones don't fit. My understanding is that the Meade Lightbridge and the Revelation dobs are both mde by GSO and share common optics and optical cell designs.

Me too

1 minute ago, Mark at Beaufort said:

I have a 12" Revelation Dob and bought these - https://www.rothervalleyoptics.co.uk/bobs-knobs-celestron-starhopper-12-primary-springs.html

 

Thanks, I've got these springs. It's the thumbscrews I'm after.

 

After some trial and error with some bolts lying round at home I can confirm the primary collimating thumbscrews for the Rev 12" Dob are M6 - hope this is helpful for anyone searching in the future.

[Mark at Beaufort]

Does this review help?

I will also look at a review that I made on replacing the primary collimation screws for my Orion VX8 which I think are the same size as the 12" Revelation. I will come  back to you on this.

This is what I ordered - http://www.wdsltd.co.uk/product/3376/hand-knob-bakelite-with-steel-insert-wds-8141/?sku=31144

[rookieoftheyear]

3 hours ago, Mark at Beaufort said:

Does this review help?

I will also look at a review that I made on replacing the primary collimation screws for my Orion VX8 which I think are the same size as the 12" Revelation. I will come  back to you on this.

This is what I ordered - http://www.wdsltd.co.uk/product/3376/hand-knob-bakelite-with-steel-insert-wds-8141/?sku=31144

Mark, that thread is extremely useful and you've done some great modifications.  I will enjoy having a good read through!  Thank you for posting.

[FenlandPaul]

On 10/01/2019 at 19:57, John said:

I'm surprised that the Meade 12" ones don't fit. My understanding is that the Meade Lightbridge and the Revelation dobs are both mde by GSO and share common optics and optical cell designs.

I was surprised by this as well, John, especially as at the time I bought my Bob’s knobs the Lightbridge ones were recommended for the Revelation. They fit for the lock-down bolts but not those for collimation. Annoying!!

That said, the recommended thumbscrews for the secondary mirror were spot on and are a dream to use!

[FenlandPaul]

20 hours ago, rookieoftheyear said:

Mark, that thread is extremely useful and you've done some great modifications.  I will enjoy having a good read through!  Thank you for posting.

I can highly recommend the handles that Mark refers to. They are excellent quality and give you complete confidence to grab the scope (which some cheap alternatives don’t).