I'm being jerked around here!!!

[Patrick1948]

:mad:I'm really enjoying my new 10" Dob, and have even found a place to store it!! (albeit in the corner of the living room!!). I'm still struggling a little with the Telrad Finder, I got the dew shield and mirror attachment so I didn't have to suffer blunt 'Neck' trauma if the dob was pointing more 'up' than at the horizontal...but the thing that is currently causing frustration is the jerky left to right and right to left movement. I did consider silicon grease for the pads on the base but was told by the shop where I got it from that would cause more 'jerks' as the temp dropped, try WD40 instead. I did and the alt movement improved but the Az was still 'jerky' though not quite as bad.....Any ideas that will make my sessions 'jerk' free would be most welcome.

Looking at all the mods done to Dobs, I am full of envy and quite inspired by what I see and I got to thinking about a system of ball bearings to swivel the scope around on, maybe ball races on a track...but alas, all my life I've been a people worker and not very good at things mechanical. If anyone has a simple bearing system and knows where I could get one knocked up, again, I would appreciate a point in the right direction.......Clear skies to you all comrades.

[Doc]

I have found that by balancing the scope correctly helps with the jerkiness. If it is balanced then maybe a lazy susan bearing for the azimuth and teflon pads for the altitude.

My altitude axis only runs on felt and it's as smooth as a baby's bum so you don't need anything special to achieve smoothness.

I wouldn't apply any wd40/polish etc as this will cause stiction, you want the surfaces as clean as possible, even a little rough to overcome stiction.

[haitch]

You could try shimming the centre bolt with washers made out of cut up plastic milk bottle. Add and remove layers until you find a good balance between smoothness and wobbly.

Useful stuff milk bottles - just upgraded a focuser with some.

[xyz]

I solved it by putting a lazy susan bearing between the base plates. The bearing was not that expensive so the balls in the bearing are not in separate cages thus sometimes they bunch up a bit and a little wriggling is needed to free them up. But otherwise it has made a major difference to the sticky rotation. In fact it rotates so easily that I have pushed in a small chunk of foam between the base plates to provide a bit of friction, else it would rotate in the breeze.

[Patrick1948]

Thanks for all your advice guys...I'll re-balance, try the plastic shims and if needed buy a 12 inch Lazy Susan for the base....thanks again.

[beamish]

Useful stuff milk bottles - just upgraded a focuser with some.

Do tell Haitch, I like things like that, you never know when it may be useful- post it in the DIY section ?? please

[ZOG]

I did read somewhere that an old LP record between the groundboard and the teflon pads smooths things out quite a bit.

[Rusty Strings]

That's what I have on my dob base and it works fine.

I tried Docs suggestion about roughing up the teflon pads to remove stiction and it worked a treat.