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Diy Sct mirror stability collet locks

Posted: Mon Jul 03, 2023 10:46 pm
by yobbo89
I havnt used my 12" meade sct In a while, I actually hate it and kind of regret not buying a Ritchey Chretien astrograph instead, I've pulled the scope appart and added thicker grease and it has reduced the mirror flop a fair bit and also modified the focuser lock to grab a little tighter, the collet ring was a little oversised so I made it a little smaller but the scope still needs to be colimated on each meridian flip

Any how I will be making a new alluminium mirror plate that has 3 contact points, I'm just woundering if anyone knows where to find these collet locking rods or if anyone knows what exactly they are called, I can make cheap ones with grub screws but I rather a collet lock with a knob.

Pulled some example images of the collet lock from users over at cn


Edit:

Re: Diy Sct mirror stability collet locks

Posted: Mon Jul 03, 2023 11:08 pm
by yobbo89
I found these, not really what I want but getting close


https://m.aliexpress.com/item/400004488 ... t=Pc2Msite

Re: Diy Sct mirror stability collet locks

Posted: Mon Jul 03, 2023 11:19 pm
by yobbo89
Some micro ones of these would be good, I can machine up some knobs, too bad all these are large 100-150mm dia

Re: Diy Sct mirror stability collet locks

Posted: Tue Jul 04, 2023 5:59 am
by Graeme1858
yobbo89 wrote: Mon Jul 03, 2023 10:46 pm Any how I will be making a new alluminium mirror plate that has 3 contact points, I'm just woundering if anyone knows where to find these collet locking rods or if anyone knows what exactly they are called, I can make cheap ones with grub screws but I rather a collet lock with a knob.

That's very inventive Rob!

Graeme

Re: Diy Sct mirror stability collet locks

Posted: Wed Aug 02, 2023 4:37 pm
by yobbo89
I finally got around to pulling the scope apart, had a few other projects to do, it seems this model also has the thread for the lx200 spring mirror stablizer add on.

Any how I'm planing on what to do before I touch anything , might machine up a inner tube to thread in the current plate to prevent it warping the thread and then tig weld two flat bar for the two collet bolts to thread into. Also glad there is No glue, the mirror is held in with cork and a o-ring with a lock ring. Very easy to get grease on the mirror, use two sets of gloves..

Re: Diy Sct mirror stability collet locks

Posted: Sat Aug 12, 2023 3:21 am
by yobbo89
I have one rod guide machined up, it took me 2 hrs
...

Wish I had a bigger parting tool xd, it will be awhile until this sct mod is completed, I also got some flocking comming in the mail aswell :).

Re: Diy Sct mirror stability collet locks

Posted: Sat Aug 12, 2023 6:34 am
by Graeme1858
Looking good Rob.

I had a mirror protector sheet that came with a heated dew ring that I didn't use when I flocked my SCT. There's only a slight touch of glue on the mirror!

Your Meade will be solid as a rock when you're done!

Graeme

Re: Diy Sct mirror stability collet locks

Posted: Sat Aug 12, 2023 12:10 pm
by yobbo89
Graeme1858 wrote: Sat Aug 12, 2023 6:34 am Looking good Rob.

I had a mirror protector sheet that came with a heated dew ring that I didn't use when I flocked my SCT. There's only a slight touch of glue on the mirror!

Your Meade will be solid as a rock when you're done!

Graeme
ohh,what did you use to flock your tube? you added the glue on the velvet aswell? i got these stick on stuff https://www.ebay.com.au/itm/36348505092 ... 2705482828

Re: Diy Sct mirror stability collet locks

Posted: Sat Aug 12, 2023 6:24 pm
by Graeme1858
Ebay has it all!

I used this:

https://www.firstlightoptics.com/telesc ... erial.html

Graeme

Re: Diy Sct mirror stability collet locks

Posted: Thu Aug 17, 2023 2:36 pm
by yobbo89
Another updated, welded the extra support lugs into the current focuser plate, welding cast alluminium is a pain, full of crud and voids which requires alot of heat and cleaning to get out,i just left a few pinholes as I didn't want to warp it with to much heat..

I just need to order 150mm long half thread hex bolts, bit of a pain to find cheap atm and machine up some locking knobs.

Re: Diy Sct mirror stability collet locks

Posted: Thu Aug 17, 2023 2:43 pm
by yobbo89
The clearance is perfect and it threads onto the mirror shaft with ease, very happy :)

Re: Diy Sct mirror stability collet locks

Posted: Sun Aug 27, 2023 6:36 am
by yobbo89
Just Waiting for brass billet to come in the mail.

Re: Diy Sct mirror stability collet locks

Posted: Tue Sep 05, 2023 2:04 pm
by yobbo89
I got a big hunk of expensive brass xd, the collet lock I'm using is called 3/16" brass brake line union inverted female Fitting , obviously the nut will be replaced with a nice machined brass knob.

I will list all the parts when I'm done if anyone wants to mod there own sct scope.

I'm wondering if it's worth while making kits to sell, the only pain is knowing the spec of the thread on the mirror tube as there will be variable sizes due fluctuations of quality control, it can be a pain designing something from one product to work on someone else's part, I've done this before on other projects and the part did not fit on another item.

Re: Diy Sct mirror stability collet locks

Posted: Sun Oct 01, 2023 3:59 pm
by yobbo89
Some more progress on the knobs , scope should be back on the mount in the next few days.

IMG_20230930_220952_927.jpg
20231001_182920.jpg

Re: Diy Sct mirror stability collet locks

Posted: Sun Oct 01, 2023 6:43 pm
by Gordon
That's a work of art Rob!

Wish you were a bit closer, I could have used your expertise earlier this week!

Re: Diy Sct mirror stability collet locks

Posted: Sun Oct 01, 2023 7:54 pm
by JayTee
It is so much fun watching you craft these improvements/accessories. You my friend, are a master machinist.

Cheers,

Re: Diy Sct mirror stability collet locks

Posted: Sun Oct 01, 2023 8:38 pm
by Ylem
You have the patience of a saint Rob, amazing work, that thing should be nice and tight. :)

Re: Diy Sct mirror stability collet locks

Posted: Mon Oct 02, 2023 9:10 am
by yobbo89
Works very well, holds tight with very eas twisting the knobs, I might make another surface pass next weekend to make the knobs a little more shiny, I think I need scotchbrite, I'm going to work on my scope flocking in the mean time.

Re: Diy Sct mirror stability collet locks

Posted: Mon Oct 02, 2023 9:12 am
by yobbo89
JayTee wrote: Sun Oct 01, 2023 7:54 pm It is so much fun watching you craft these improvements/accessories. You my friend, are a master machinist.

Cheers,
Thanks, I just watch youtube videos, never really knew how to use a lathe before hand :)

Re: Diy Sct mirror stability collet locks

Posted: Mon Oct 02, 2023 9:15 am
by yobbo89
Gordon wrote: Sun Oct 01, 2023 6:43 pm That's a work of art Rob!

Wish you were a bit closer, I could have used your expertise earlier this week!
Happy to machine you something up xd