HELP PLEASE!!

[bosun21]

I have just finished building my newly delivered Stella Lyra 12” dobsonian and the focuser won’t move in any direction. The draw tube can be lifted loosely up and it just falls straight down. The axis of the focuser knobs also has lateral and vertical play. I’m peeved as I’ll be dammed if I have to strip it all back down to return to FLO. Any ideas anyone?

 

 

[Cornelius Varley]

The two thumbscrews on the base act as a focus lock and the other as friction adjustment for the crayford (can't remember off hand which does which) .Tightening the thrumbscrews should help.

[markse68]

Are there not screws for adjusting the tension on the spindle against the draw tube? There are usually near the locking screw

Mark

[Guest]

There are two little silver screws right in the middle of the focuser.  The top one is resistance, the bottom one is a lock.  Turn the top one in

Edited January 13, 2023 by Mike Q

[bosun21]

12 minutes ago, Mike Q said:

There are two little silver screws right in the middle of the focuser.  The top one is resistance, the bottom one is a lock.  Turn the top one in

Come now Mike I’ve been doing this for a little while now 😂 I know all about the tension adjustment and the focus lock screw. That’s the first thing I tried. With the tension screw tightened to maximum the draw tube still won’t move but it’s loose to lift out and if you let it go it just drops like a stone. The four screws that fix it to the tube were really loose and the entire focuser was moving side to side. Quality control is non existent here. Did you watch the video I posted?

[bosun21]

23 minutes ago, Cornelius Varley said:

The two thumbscrews on the base act as a focus lock and the other as friction adjustment for the crayford (can't remember off hand which does which) .Tightening the thrumbscrews should help.

They don’t do anything at all apart from the lock screw will stop me being able to lift out the draw tube. When I do and let it go it drops like a stone.

[Guest]

Yeah i did, mine did the same thing until i turned the two silver screws then all was good.  In the video it doesn't look like they are turned in at all.. 

Edited January 13, 2023 by Mike Q

[markse68]

it must be missing a thrust plate inside or maybe it came loose and is rattling around in there?

Mark

[bosun21]

26 minutes ago, markse68 said:

Are there not screws for adjusting the tension on the spindle against the draw tube? There are usually near the locking screw

Mark

Yes there are three small screws. One in between the two thumb screws and two below them. I tried various combinations of different positions for them to no avail. I reckon they may be a push/pull set up so I am going to remove the focuser and strip it down completely to see exactly what’s going on internally. The entire focuser was loose on the tube and was moving side to side. I didn’t expect this grief after unboxing a new scope.

[bosun21]

7 minutes ago, Mike Q said:

Yeah i did, mine did the same thing until i turned the two silver screws then all was good.  In the video it doesn't look like they are turned in at all.. 

It’s absolutely nothing to do with the two silver thumbscrews. I’ve had the tension screw all the way in and it does zero.

[markse68]

6 minutes ago, bosun21 said:

Yes there are three small screws. One in between the two thumb screws and two below them. I tried various combinations of different positions for them to no avail. I reckon they may be a push/pull set up so I am going to remove the focuser and strip it down completely to see exactly what’s going on internally. The entire focuser was loose on the tube and was moving side to side. I didn’t expect this grief after unboxing a new scope.

I don't know that specific focuser but on my Moonlite there's a block of PTFE in between the screws and the focuser spindle and on my Feathertouch it's a block of steel I think that acts like a lever against the spindle to apply pressure/lock it. My guess is yous would have something similar that has fallen out- hopefully it's still there and you can sort it out on disassembly 🤞

Mark

Edited January 13, 2023 by markse68

[bosun21]

12 minutes ago, Mike Q said:

Yeah i did, mine did the same thing until i turned the two silver screws then all was good.  In the video it doesn't look like they are turned in at all.. 

They have been in every position you can possibly imagine.

[Guest]

4 minutes ago, bosun21 said:

It’s absolutely nothing to do with the two silver thumbscrews. I’ve had the tension screw all the way in and it does zero.

Well drat

[Guest]

1 minute ago, bosun21 said:

They have been in every position you can possibly imagine.

Let me go look at mine

[bosun21]

1 minute ago, markse68 said:

I don't know that specific focuser but on my Moonlight there's a block of PTFE in between the screws and the focuser spindle and on my Feathertouch it's a block of steel I think that acts like a lever against the spindle to apply pressure/lock it. My guess is yous would have something similar that has fallen out- hopefully it's still there and you can sort it out on disassembly 🤞

Mark

That’s the plan I have started to do. These SL Crayfords don’t have any type of plate that you can remove unlike all others I’ve seen. I am going to upgrade it to a R&P maybe a Baader steeltrack or similar.

[Franklin]

If it's new I would just contact FLO, they'd probably just send you a new focuser unit out and then just swap it over. 

[Guest]

So i went out and messed with my Orion which is essentially the same scope.  I have no play at all like you show at the end of the video.  Me thinks you have a bum focuser.  I would send that video to FLO before i did another thing. 

[Guest]

Here is my focuser adjusted for drag and the length of the resistance screw.... Call the threaded area a strong quarter of an inch, so 8mm or so of threads? 

[bosun21]

2 minutes ago, Mike Q said:

So i went out and messed with my Orion which is essentially the same scope.  I have no play at all like you show at the end of the video.  Me thinks you have a bum focuser.  I would send that video to FLO before i did another thing. 

I know but I really can’t be doing with the hassle. If I can’t fix it I’ll just buy a new R&P Baader Steeltrack.

[knobby]

As an engineer I'm finding this so frustrating 🤣 I just want to get my hands on it !

Wish you the best of luck though.

[bosun21]

Cracked it! Inside the focuser there is bearing plate that has adjustment grub screws which were all loose causing no friction on the draw tube. I tightened them a few turns and replaced the draw tube. Better but not right enough. Rinsed and repeat until it’s now how it should be. I am still going to upgrade this Crayford in the very near future. Now to replace the primary springs to a heavier gauge of wire and fit my aluminum Bobs knobs on my secondary holder. Gauging by the QC on this I wonder how far the collimation is out. I have also bought a heavy duty roller bearing for the azimuth movement but I want to ensure it’s optically sound before I poke screw holes in the baseplate voiding the warranty. It’s a labor of love for me. Thanks for everyones input. It’s appreciated.

        Ian 

Edited January 13, 2023 by bosun21
Typo

[bosun21]

14 minutes ago, knobby said:

As an engineer I'm finding this so frustrating 🤣 I just want to get my hands on it !

Wish you the best of luck though.

I am actually an electrical engineer myself (retired) Cracked it once I got to grips with the internals.

[Guest]

22 minutes ago, bosun21 said:

Cracked it! Inside the focuser there is bearing plate that has adjustment grub screws which were all loose causing no friction on the draw tube. I tightened them a few turns and replaced the draw tube. Better but not right enough. Rinsed and repeat until it’s now how it should be. I am still going to upgrade this Crayford in the very near future. Now to replace the primary springs to a heavier gauge of wire and fit my aluminum Bobs knobs on my secondary holder. Gauging by the QC on this I wonder how far the collimation is out. I have also bought a heavy duty roller bearing for the azimuth movement but I want to ensure it’s optically sound before I poke screw holes in the baseplate voiding the warranty. It’s a labor of love for me. Thanks for everyones input. It’s appreciated.

        Ian 

Your collimation.... You WILL be out.... By miles and miles.  As a heads up, after changing the springs, one of the adjustment knobs may seem a bit tighter then the others.  This appears to be normal. 

Edited January 13, 2023 by Mike Q

[bosun21]

55 minutes ago, Mike Q said:

Your collimation.... You WILL be out.... By miles and miles.  As a heads up, after changing the springs, one of the adjustment knobs may seem a bit tighter then the others.  This appears to be normal. 

This is exactly what I have found. Put in my Hotech laser collimator and the laser was on the ceiling. Sacked that and resorted to a Cheshire and collimation cap. Talk about way out!. I’ve now got it almost bang on with everything concentric and the donut bang centre. I will fine tune it tomorrow when I buy some new batteries for my Hotech (they died). Changing the primary springs was a pain compared to the 8” but all done and dusted now. Just got the heavy duty roller bearing to fit after I’ve had first light.Want to make sure it’s a keeper before I void the warranty by making screw holes on the base 

[bosun21]

3 hours ago, Franklin said:

If it's new I would just contact FLO, they'd probably just send you a new focuser unit out and then just swap it over. 

I would be perfectly happy with that but I ain’t sending the whole scope back, disassembling the Dobson mount etc. Major pain in the proverbial.