ES Twilight II altitude motion
Posted 25 May 2013 - 09:25 AM
Posted 25 May 2013 - 01:35 PM
Maybe some dust contaminated the altitude bearing surface and needs a cleaning. Not sure if to access it just involves removing a tangent arm and slipping out the altitude bearing assembly.
Posted 25 May 2013 - 01:58 PM
Posted 25 May 2013 - 04:13 PM
I have an ADM dovetail on the other side that carries 11 lbs. of counterweight. ES says the counterweight isn't necessary, but there's a little less stiction with it in use.
I'm going to cautiously take it apart and see if it's gunked up.
Posted 25 May 2013 - 04:31 PM
Posted 25 May 2013 - 07:39 PM
I wasn't able to completely disassemble the altitude parts, but I was able to remove the saddle, silver retaining ring, and black nylon washer on each side. I could barely rotate the altitude motion by hand at that point, but was able to shove the assembly over to one side. I found a couple things--the usual thick grease that looked like it had accumulated some grime, plus some black thread-like pieces that looked like they had been shaved off the nylon washers or some internal part I couldn't get at. I wiped off the grease, added a little Novagard G661 Silicone Compound (same lubricant I use on the azimuth), and reassembled.
The only hiccup was that I had inadvertently moved something about an eight of an inch to one side, so that one of the silver retaining rings was obviously jutting out further than the other. (The part was a black ring inside one of the side holes--not sure how to describe it other than that.) With the whole assembly back in place, I gave one saddle a tap with a washcloth-covered hammer and everything slid back to center.
Before I started this adventure the altitude motion had been stuck to the point that the scope needed only a very rough balance and needed way too much pressure to move. Either the grime or the nylon threads might have been enough to hang it up. Now it moves easily (maybe a little too enthusiastically) so that the altitude needs the top tension knob engaged just a little to be able to change eyepieces without the scope moving.
Jim, thanks for the input to look for grime. That seemed to do the trick.
Posted 09 September 2013 - 03:54 PM
Been considering buying one myself, but there's very little owner feedback out there... Any idea what kind of bearings, if any, are used in both axes? Or just metal on metal with grease as a lubricant?