Sloppy focuser

[TheThing]

The Soligor scope has only one downfall at present. The original R&P focuser is a bit sloppy. Not too bad at low mags, but as you get higher, the object you are trying to focus on can move right out of the FOV while you fiddle with the knobs. The 'draw tube' (as I call it) with the EP in seems to move up whilst you rack out (but not down when you rack in).

There is a littel grub screw atop the focuser, which I've finger tightened as much as I dare, but to no avail.

I don't really want to go to the expense of changing the focuser, so is there any sort of repair or bodge I can do to cure the problem? (please remember that I'm quite hamfisted and will need it explaining like I'm a 6 year old!)

Many thanks!

[TheThing]

Anyone? :crybaby:

[GazOC]

Strip the focuser and glue 2 shims at roughly the 10 o'clock and 2 o'clock postions along the length of the tube to force it down onto the rack. Strips of PTFE or similar would be ideal.

[TheThing]

Gaz, sir, you are a genius!

So simple, so obvious and yet beyond me!

Thank you kindly.

Um, where would one purchase PTFE?

[kniclander]

not sure if this will help but my old 6" dob had a sloppy focusser and any adjustments I made to tighten it just meant it got too stiff to use. When I collimated it I found that collimation was spot on when I focussed in but off when I focussed out so I always focus in when i make my final focussing adjustments. So my focusser is still sloppy but I know the right way to "slop" it so as not to lose collimation.

ps - not sure if it made any difference to the view with my 6" but it made me happy

[kniclander]

Strip the focuser and glue 2 shims at roughly the 10 o'clock and 2 o'clock postions along the length of the tube to force the it down onto the rack. Strips of PTFE or similar would be ideal.

...or I could of done that :oops: . What is PTFE?

[GazOC]

If you search Ebay for "PTFE sheet" there are several sellers. You'll have to estimate how thick a strip you'll need, but as long as you err on the large side you can always file a few millimeters off as required,

[lunator]

Gaz

Is the resident creative engineer on SGL

TT let us know how this works out.

Cheers

Ian

[jgs001]

Thing, I used some teflon tape I got from a mouse shop on my Konus. Worked a treat... I used to get the draw tube slopping up and down like mad, really obvious under high mag. No more. this is the stuff. I did the strip and regrease and tried all sorts of other adjustments but this did it in the end... Now, even with the 450d liveview at 10x zoom (how I focus) the central star I'm focusing on doesn't move due to changing focus.

[George]

There;s a couple of threads in the DIY section if i remember correctly, a search should bring them up.

[themos]

I bought a 3mm PTFE sheet off ebay, I hope it's not too thick for the application...

[TheThing]

Thanks to everyone for their help and advice - SGL REALLY is the BEST!

BIG thanks to John who is sending me some of his marvelous mouse tape! What a superstar!

[Grotemobile]

Iv just had a problem like this with the second hand scope iv just got.Under neath the focuser there

four little screws Mine were loose & this was the problem .I stripped the focuser down & inside was

a piece of packing .Iv just put it all back ,& Problem solved .You can but give it a try .

Steve

[jgs001]

Steve, it might work on Things focusser, I did all that and it wasn't enough on mine, that's why I got the tape.

[ChrisEdu]

Strip the focuser and glue 2 shims at roughly the 10 o'clock and 2 o'clock postions along the length of the tube to force the it down onto the rack. Strips of PTFE or similar would be ideal.

...or I could of done that :oops: . What is PTFE?

PTFE is Teflon, polytetrafluroethylene!