Just a quick hint on getting smoother azimuth motion.
On my 12" Dob ,my centre pin assembly is made out of crappy stainless rolled tube, which isnt even round.
The bolt is also very sloppy and rides on the "thread part".
What I have done is got 1 off Stainless bolt (10mm), with a straight shank of 35mm. I then machined up a brass bush that fits perfectly over the new bolt and sits inside the original hole in the wood. Some good quality grease also in the bush for good measure.
I also machined up a teflon centre bush, exactly 3mm diameter (same height as the outer 3 stock sliders.) And lastly, I made up thicker and wider stainless steel washers to replace the crappy cheap ones on the 2 outer surfaces.
This new bearing assembly worked way better than I expected. My 12" scope can now be pushed around with my pinky finger, even at the zenith. This is not an exaggeration.
On my scope anyway, I am certain that the centre assembly caused the bulk of the "drag" in stock form. Maybe people should also look at this part of the assembly at getting better motion as it is not often discussed here?????
btw, lastly I put car polish on all the sliding surfaces of the dob.
(I will post pics of my modsas soon as I borrow works camera)
My 12" GS Dobbie used to move in Azimuth with just a pinky too!
And because of that, the slightest breeze and stars would Zoooooommmm across the FOV.
That's why I took the stupid roller bearing out!! So it wouldn't. Mine now moves with more friction. I leave the centre bolt loose and run it on teflon Super-Sliders. Suits me, and everyone to their own.
My 12" GS Dobbie used to move in Azimuth with just a pinky too!
And because of that, the slightest breeze and stars would Zoooooommmm across the FOV.
That's why I took the stupid roller bearing out!! So it wouldn't. Mine now moves with more friction. I leave the centre bolt loose and run it on teflon Super-Sliders. Suits me, and everyone to their own.
My fix was intended to make the movement more smooth, because in stock form I would have to jerk it around, which resulted in overshooting the target.
Now it moves real smooth. To be honest I have not thought about it being too easy to move, but all I would need to do is to tighten the locknut slightly to stop movement from the breeze.
Unfortunately Mark, If you tighten the centre bolt it will loosen as you turn the scope. That's why I leave mine loose now. Coz it just loosens anyway.
I have found that replacing the bearing with teflon sliders the action is fairly smooth and no jerking.
Unfortunately Mark, If you tighten the centre bolt it will loosen as you turn the scope. That's why I leave mine loose now. Coz it just loosens anyway.
I have found that replacing the bearing with teflon sliders the action is fairly smooth and no jerking.
Do you still use the Roller bearing?
My scope never had roller bearings.
It came with the square teflon sliders.
My centre nut is a 10mm Nylock nut, it has never loosened once. Maybe your bolt is too short so your not engaging in the nylon part of the nut????
Same set up as yours was originally. Nylock was engaged into nylon section. I took it apart too many times and wore out the nylon. Works good how it is now though.
Glad yours works better. That sticking would have been a nuisance.
A simple tip for ALL. To stop 'nuts' etc from coming loose, why not use ordinary NAIL LACQUER? It works a treat. Better & cheaper than Loctite, with your choice of colours, if you're that way inclined! L..
ps. I use the clear one myself!
And don't forget to use an Eyeliner to mark your Sky Maps, or to smear Red lipstick on the front lense of your white-light torch!
p.s. I use the Luscious Rose one myself!
Mark, interested to see some pics when you have them!
You can get a nylon locknut to place over the centre bolt to stop it from loosening when you turn the scope.
To improve the motion on my dob, I used an axel bearing on the rocker base. It lets me adjust the azmuth friction by tightening the wing nut a bit. The bearing keeps the wing nut from unthreading. Works Great
Sorry Mike. Got carried away slightly.(Blame Ken). Will delete if nec. Still, my first post re; the nail varnish/lacquer is relevant to this problem guys. It works a treat. No more loose nuts & bolts, + it's waterproof & cheap. L.
well i went the expensive route with loctite... my bolt we well and truely long enough but it still kept loosening. now it doesnt... ez-sliders helped my az motion.
L.. 
Just name the time & place! 
