Missing Screw on Skywatcher focuser HELP

[Simon Dunsmore]

Hi,

One very frustrated individual here. So I attempted to fix my new EAF to my 72ed today. Wish I had never started.

First off, the little Alan club Screw required to remove the course focuser rounded off and now I can't remove it.

Then I dropped the  tensioner grub Screw and so can't even revert back to manual focus. 

Would anyone know what size the grub Screw is and possibly suggest how to remove the course focuser knob from the shaft?

Please help!!!

Thanks

Simon

[fozzybear]

42 minutes ago, Simon Dunsmore said:

Hi,

One very frustrated individual here. So I attempted to fix my new EAF to my 72ed today. Wish I had never started.

First off, the little Alan club Screw required to remove the course focuser rounded off and now I can't remove it.

Then I dropped the  tensioner grub Screw and so can't even revert back to manual focus.  2.5 Allen Key for that One as two of them M5 grub screw

Would anyone know what size the grub Screw is and possibly suggest how to remove the course focuser knob from the shaft? Maybe someone else with engineering skills bit beyond me.

Please help!!!

Thanks

Simon

Simon

Hope this helps the tensioner grub screws x2 are 2.5 Allen key so M5 grub

as for the rounded off one maybe someone with better help could help you on that one. You could try a T8 torx but add some penetrating fluid and try to tighten first just a little then undo might work or hang on for other help

Edited December 28, 2021 by fozzybear
added text

[Simon Dunsmore]

Thanks for your help. May just try and get it drilled out. 

[fozzybear]

Found this old link by @Philip R 

 

[Budgie1]

Make sure it's the grub screw that's rounded off and not just the allen key. 

If the grub screw has rounded then you have a few options:

• Remove the focuser from the scope and try a bit of heat on the focuser knob to expand it, then try the 2mm allen key again (if it has any grip at all). I'm not talking about a welding torch or anything here, just holding it under the hot tap may provide enough heat.
• Try to get a 3/32 inch allen key into the grub screw, this is slightly larger than the 2mm but may need to be forced into the grub screw (with a hammer or press) so be careful!
• Drill out the grub screw using a Pillar Drill. Don't try to do it freehand because you're more likely to damage the internal thread of the course focuser knob. The drill size for tapping an M4 thread is 3.3mm, so try a 3mm drill to remove the grub screw, but watch the depth you're drilling too as you don't want to drill into the shaft. Once removed, you'll have to get the remains of the thread from the grub screw out of the threaded hole in the course focuser knob if you want to use it again.

[Simon Dunsmore]

It may just be easier to replace the bar. Any idea what length the bar is? I can measure the diameter.

Thanks 

[Simon Dunsmore]

Just in case anyone wants to know. I sorted this by  buying a new length of 4mm bar and cut it to length. I replaced the missing grub screw with a new 5mm m5.

EAF fitted and working like a dream. Just need some clear skies.

Thanks for your help and may all your skies be clear in 2022

[fozzybear]

glad you got it sorted