4 replies to this topic

[Joelsfallon]

Hello,

 

I haven't had my mount for more than a year, and it's always had a stiff/sticky RA + Dec shaft which makes balancing more or less guess work. I'd like for it to be fluid, but I can live with it for now. 

 

The main issue I'm currently having (of which I've noticed some months back but it disappeared) is there seems to be a knot in the RA movement near meridian (horizontal). With clutches released, I can feel what I can only describe as the bearing catching on something internally, like a burred edge / grit in the bearings, or the RA shaft collar is deformed as is catching on the shaft. This effect is most noticeable when moving the RA slowly.

 

The effects of this issue results in the inability to guide. PHD2 struggles to calibrate in west (stays still, sometimes shifts east). Balancing the counterweight west-heavy does not solve this issue. If I am able to get a successful calibration at a different area of the sky, the RA can not correct its east drift.

 

The mount was working fine a week ago - the only thing I can think of is that I may have bumped the mount with the clutches engaged and it caused the clutch bolt to scrape on the collar. I figured I best ask here before I break down the entire mount and examine the entire assembly. 

 

As per the first sentence, does anyone have any recommendation as to how I can eliminate the shaft stiffness for balancing?

 

Thank you!

[Wei]

There is a lock ring inside that you can loosen to make it smoother.  If you have stuff on your worm you will need to clean and regrease. When you try to take the mount apart will see this lock ring.

[Joelsfallon]

Thank you Wei, I have found a few topics on this thrust bearing nut. I hope that is all I need to do to solve the stiffness. I will give it an adjustment to see if it improves!

[EFT]

Rest assured that your axis shaft and clutch is just fine.  This is fairly typical of the EQ6 and prodigy mounts.

[Joelsfallon]

An update for those who may come across this post post in the future.

 

I managed to resolve the issue by loosening the thrust bearing nut at the base of the RA shaft. After removing the polar scope and metal cuff, I used an adjustable pin wrench to tackle the bearing. This bearing was on tight, though. How they come out of the factory line this tight is beyond me - the assembly worker must've went to town with this nut. I had to hit the wrench with a hammer to get any sort of movement. Not something I wanted to do nor recommend to anyone else, but this thing was just welded on. A good half turn was all I needed!

 

The shaft rotates freely, and there is zero play. So far, no more knots can be felt, and balancing is no longer guesswork. My total RMS was 0.54 arc seconds after a 6 hour imaging session.