Declination gets locked


Suresh Mohan
 

After a nights session , after unlocking the clutches it takes much strength to initially move the dec axis , have no problem to slew or track only to initiate rotation it requires an effort and then I feel it giving way and able to rotate it . Are the gears binding ? Unlikely bcos I can even feel a discrete backlash . Everything is greased as well . Pls let me know ur thoughts
Suresh


 

Hi Suresh

if you are unlocking the clutches and moving the axis, your movements are independent of the gearing, so the gears/backlash/mesh would not impact your movements in any way. 

maybe make sure you completely loosen the clutch


Brian

On Sun, Mar 1, 2020 at 5:36 PM Suresh Mohan <drsureshmohan@...> wrote:
After a nights session , after unlocking the clutches it takes much strength to initially move the dec axis , have no problem to slew or track only to initiate rotation it requires an effort and then I feel it giving way and able to rotate it . Are the gears binding ? Unlikely bcos I can even feel a discrete backlash .  Everything is greased as well . Pls let me know ur thoughts
Suresh





--
Brian 



Brian Valente


Suresh Mohan
 

Yes of course Brian , I’ve no issues with RA , it’s just the DEC - I  get a jammed feeling at start , the effort required is abnormal 
Suresh 


On 02-Mar-2020, at 7:37 AM, Brian Valente <bvalente@...> wrote:


Hi Suresh

if you are unlocking the clutches and moving the axis, your movements are independent of the gearing, so the gears/backlash/mesh would not impact your movements in any way. 

maybe make sure you completely loosen the clutch


Brian

On Sun, Mar 1, 2020 at 5:36 PM Suresh Mohan <drsureshmohan@...> wrote:
After a nights session , after unlocking the clutches it takes much strength to initially move the dec axis , have no problem to slew or track only to initiate rotation it requires an effort and then I feel it giving way and able to rotate it . Are the gears binding ? Unlikely bcos I can even feel a discrete backlash .  Everything is greased as well . Pls let me know ur thoughts
Suresh





--
Brian 



Brian Valente


 

Hi Suresh,

yes I understand. both axis work the same re: the clutches. 

my ap1600 is also stiff/sticky regarding balancing, not sure if that's just the way it is. 



On Sun, Mar 1, 2020 at 6:19 PM Suresh Mohan <drsureshmohan@...> wrote:
Yes of course Brian , I’ve no issues with RA , it’s just the DEC - I  get a jammed feeling at start , the effort required is abnormal 
Suresh 


On 02-Mar-2020, at 7:37 AM, Brian Valente <bvalente@...> wrote:


Hi Suresh

if you are unlocking the clutches and moving the axis, your movements are independent of the gearing, so the gears/backlash/mesh would not impact your movements in any way. 

maybe make sure you completely loosen the clutch


Brian

On Sun, Mar 1, 2020 at 5:36 PM Suresh Mohan <drsureshmohan@...> wrote:
After a nights session , after unlocking the clutches it takes much strength to initially move the dec axis , have no problem to slew or track only to initiate rotation it requires an effort and then I feel it giving way and able to rotate it . Are the gears binding ? Unlikely bcos I can even feel a discrete backlash .  Everything is greased as well . Pls let me know ur thoughts
Suresh





--
Brian 



Brian Valente



--
Brian 



Brian Valente


Joe Zeglinski
 

Hi Suresh,
 
    Has the DEC always seemed a bit more sticky than the RA rotation ?
 
    I wonder if it is just because the OTA momentum is much lighter  than the counterweights,  offsetting the momentum on the RA swing. For the “same amount” of axial friction on your well greased axles, pushing the well-(fore/aft) balanced OTA, might present more friction, whereas there may be more momentum when you push the same OTA & CWTS,  about the RA axis.
 
    Once the RA direction gets going, the scope might seem easier to push further. Not the same case  rotating the tube vertically on the DEC axis, unless there is a humongous CCD camera at one end  of the balanced OTA, to add some momentum like the CWTS do , once initial DEC axle stiction is overcome.
 
    Mechanically, there should be absolutely no difference in the smoothness of either axle, once the clutch brakes are released – the gears aren’t involved at that point.
 
    Just a thought.
Joe Z.


Steve Salvo
 

I’m not sure of the model mount you have, but on my mount, the 900, the friction pads under the clutch locks can depress and warp, actually hindering the movement of the axis. AP has a special tool to remove the pads. This happens by over tightening the clutches.

Steve

On Mar 1, 2020, at 20:36, Suresh Mohan <drsureshmohan@gmail.com> wrote:

After a nights session , after unlocking the clutches it takes much strength to initially move the dec axis , have no problem to slew or track only to initiate rotation it requires an effort and then I feel it giving way and able to rotate it . Are the gears binding ? Unlikely bcos I can even feel a discrete backlash . Everything is greased as well . Pls let me know ur thoughts
Suresh



Joe Zeglinski
 

Steve,
 
    Yes, the old AP-900 and AP-1200 mounts had nylon clutch (cylindrical) plugs, which do flatten out “into the narrow free space between the axle and the threaded bolt shaft. It ends up looking like a  “mushroom” inside that tight channel space. At that point, with the nylon now partially jammed between axle and housing, it becomes very difficult,  almost impossible to rotate the axle by hand. The flattened plug head can’t be extracted the same direction it went in, and it also mushrooms itself into the threaded walls of the bolt hole, so it becomes stuck into the wall’s threads.  As I recall, the only option is to force the entire  axle out of its outer housing, (using 3” long, screwed-in “push bolts”, from the axle top head-end), drill out most of its center to a thin walled cylinder, then hammer the remaining mushroomed nylon plug inward, for removal. Extremely difficult repair task.
 
    I bought the AP extraction tool, which I was even advised up front,  by staff that it likely wouldn’t work very well as it chipped the plug material. The tool is just  a specially filed down screwdriver – and I followed the instructions. The tool just ate away at the old,  compressed, now age-brittled plug with every turn of the blade and never got a grip on the plug for extraction. 
 
    In fact, it probably works in rare cases, of newer plugs that weren’t tightened down all that much over the years – certainly NOT using  an Allen wrench on the axis lock down bolt head!
The guys at AP certainly deserve their well earned praise and admiration of doing such a difficult job in plug repairs. I don’t envy them at all, but appreciate their personal hard work.
 
Joe Z.


Astrobob
 

I believe your supposed to put a drop or two of oil down the thread holes of the clutch bolts on occasion.

 

Bob


Roland Christen
 

 
. Are the gears binding ? Unlikely bcos I can even feel a discrete backlash .  Everything is greased as well . Pls let me know ur thoughts
The gears have nothing to do with the clutch. two different things completely.
 
Rolando
 
 
-----Original Message-----
From: Suresh Mohan <drsureshmohan@...>
To: main <main@ap-gto.groups.io>
Sent: Sun, Mar 1, 2020 7:36 pm
Subject: [ap-gto] Declination gets locked

After a nights session , after unlocking the clutches it takes much strength to initially move the dec axis , have no problem to slew or track only to initiate rotation it requires an effort and then I feel it giving way and able to rotate it . Are the gears binding ? Unlikely bcos I can even feel a discrete backlash .  Everything is greased as well . Pls let me know ur thoughts
Suresh