Vibrations when slewing RA? Help please!

[oymd]

Yesterday I noticed that there is a very fine and subtle vibration in my scope when my AZ-EQ6 Pro was slewing in RA. 

I had already been struggling with guiding for the last week, and my RA would go up to 7rms for no obvious reason. 
 

I used to have constant 0.5-0.7rms, and over the past month or so the RA had been terrible. 
 

I stripped the mount today, and I seem to have found a problem. The worm shaft is VERY rough when I turn it by hand and NOISY. 

It seems the bearings are gone. Mount is just 2 years old. 

The same one on the DEC is silent and buttery smooth  

Any idea what I should do? Grease? WD40?

Is this replaceable or serviceable?

Many thanks

 

Edited February 9, 2022 by oymd

[oymd]

Are those two bearings these by any chance?

https://www.tme.eu/en/details/skf607-2z_c3/roller-bearings/skf/607-2z-c3-skf/

607-2Z/C3 SKF  SKF

[oymd]

I’d appreciate it if someone can supply the model numbers for these bearings?

I measured the worm shaft at 14mm (this would be the inner diameter of the opening in the bearing) and the external diameter of the bearing at 22mm

I cannot find any bearings on SKF website that has those dimensions?

 

[markse68]

you need to pull the bearing off the shaft- it won’t be 14mm where it goes through the bearing- it’ll narrow down I think- probably the diameter of where it passes through the pulley in your photo

Mark

[oymd]

3 hours ago, markse68 said:

you need to pull the bearing off the shaft- it won’t be 14mm where it goes through the bearing- it’ll narrow down I think- probably the diameter of where it passes through the pulley in your photo

Mark

Thank you for your reply.

Can you please advise how to pull the shaft out of the bearings? The pulley has two grub screws on the shaft, but removing those did not make a difference?

How can I dismantle this part?

Many thanks

Edited February 10, 2022 by oymd

[oymd]

I Thought I would update this thread I started.

I replaced the bearings on the RA worm shaft with SKF 608-2Z.

I fine tuned the backlash manually on both axis while the mount was stripped, and did some further tuning with Guiding assistant.

As of last week, the mount is behaving very well, with my guiding at 0.30 to 0.50 rms, constant, depending on the seeing.

Very happy here...

Especial thanks to @wimvb for all his help and patience in getting me over the line!!

Here is my first project after fixing the mount: IC 2177, the seagull nebula, taken during full moon over 6 nights, with loads of subs discarded...

103L, about 8 hours.

 

[teoria_del_big_bang]

I do like a happy ending 🙂 

Great images.

Steve

[wimvb]

👍