Another focuser stuffed...

[codemonkey]

Not to be confused with the other thread "Focuser stuffed."

I was having similar problems as Morton was in his thread with the focuser grinding on my Skywatcher BD ED80. I'd ignored it as everything was still functional, but now things have escalated.

At this point the focuser won't hold any weight at all now unless the focus stopping screw is done up very tightly. If the focus stopping screw is not done up, the whole draw tube will fall immediately without restriction when the OTA is moved one way or the other.

Does anyone have any idea how I can fix this? It's my only scope so I'm hesitant to send it back (purchased from interstate... and I've already had to send back my nexstar handset once, my handset & mount once, and my CCD once... sick of sending things back and having to wait) if I can fix it myself. Alternatively maybe I'm better off just buying a new focuser (any suggestions?) as everyone seems to have problems with these regardless.

[Pinwheel]

I'd suggest either pull it down & replace the damaged components or if your not mechanically minded take the focuser to Bintel for repair or replacement. Probably cheaper to buy a new focuser.

[LewisM]

A new focuser for these is $199 at Sirius Optics in Brisbane.

Fixing a Crayford is easy enough - I had to rebuild the ED80 focuser I had. Just disassemble, check all is good (no rust etc - I had an Orion/Skywatcher Mak-Newt once with quite advance rust on the pinion, and had to fix that), and reassemble, making sure that the teflon cradle is square (not angled), and to tighten the draw screws on the bottom (the 4 grub screws). You may find just tightening the 4 grub screws a fraction helps WITHOUT needing to disassemble.

And if all that fails, or you actually want ti to hold more than 1/2 a KG of weight, add a section of shrink tube to the pinion shaft if you take it apart. Not as smooth afterwards because of radically increased tension (and will hold about 3 kg in my test), but still plenty smooth enough.

[DJT]

There is a specific post on this subject on another forum

http://www.astronomyshed.co.uk/forum/viewtopic.php?f=43&t=4932

I used the same trick on an ED100, its a simple fix

good luck

[codemonkey]

Thanks for your help guys, I appreciate it :-)

I did find that post on the Astronomy Shed forum, but I had no luck when adjusting the 'B' bolts and tightening the four grubs (marked 'A'). I'll have another shot when I get home tonight.

Is there anything else that could affect this? I noticed in the OTA there's some brackets which hold some... things, that rotate. I assume they're positioned to sit flush against the draw tube and facilitate the movement of it. Could those things need to be adjusted?