sticking dob mount advice please.

[rory]

okay ive had a good three or four sessions with the 8" dob now and im on the whole very happy with it. one problem i have is getting the the elevation movement just right between stiction, tension handles,and balance. the main issue that i feel will really start to nark me soon if i dont sort it ,is when im viewing something quite happilly and i need to nudge it to keep it in view i get this stiction problem where instead of sliding up or down it needs to break stiction first, so the first couple of mm is a jump rather than slide. as you can imagine on higher magnification it becomes a pain.

so just a case of practice or is there much i can do ? the base swivels nice as pie since the old milk carton trick, but just cant seem to get the elevation just right.

there were two lead weights stuck on the base, quite large ones from previous owner, ive removed one as i felt it was to bottom heavy. ive also silicone polished the teflon studs,but after all this its still a little iffy . so any tips or ways to correctly balance ect,id appreciate it .

clear skies... and smooth mounts

[sunshine185]

I used some plastic milk bottle washers, the part of the bottle near the top is slightly bumpy on our milk bottles, I cut 2 big pieces and made a hole in the middle so the handle bolt could fit through, then put the ota on the side bearings and slid the washers down each side, it made it very smooth.

[umadog]

I find that if the materials are right then the motions are right. Lubricating can create a surface layer which increases static friction and decreases dynamic friction. That's bad and sound like what you're seeing. I would clean off the lube and look into an ebony star upgrade for the bearings.

[knobby]

I'd second what umadog said, clean off any lub and try it ... shouldn't need lub!

[rory]

okay cheers guys .i'll wipe it all down and try it.

[knobby]

good luck

[rory]

i was out for an hour or so last night and even though the large black discs on the dob have been wiped over several times theres still an issue for me with movement. im not getting on with the dob mount very well at all, although im very happy with the views.

i dont know if its my imagination or what ,when i check it in the house it seems better than when im outside and its cooled ? probably just me. i feel some modifications coming on before proper winter observing comes around ,otherwise this mount problem will ruin the hobby.

[Mike73]

I found exactly the same problem with both my 8" and 12" SW Rory.

Adding a lazy Susan for for azimuth helped but there us still a 'wobble' with the bearings and the altitude is pretty tricky to get the correct sticktion.

Only way around it is to build your own base or buy one from OOUK.

For the money SW dobs are amazing but the base really is the weakest link IMO.

[ollypenrice]

Not all sillicone polishes are equal. I use Turtle Wax and I once changed to a different (French) make of sillicone polish. Disaster! I had exactly the problem you describe and the scope was barely worth using. An emergency supply of Turtle Wax sent out from the UK was the only solution.

Olly

[rory]

okay, i'll try turtle wax. thanks.