Skywatcher AZ EQ6GT Service - DIY or send it away

[Jonny_H]

I have a Facom 117.B adjustable pin wrench which is great. A little on the pricey side but they have been a lifesaver!

[dannybgoode]

44 minutes ago, Jonny_H said:

I have a Facom 117.B adjustable pin wrench which is great. A little on the pricey side but they have been a lifesaver!

Now isn’t that just the puppy! I’ve just bought a 3’ steel bar and some M4 bolts to make a suitable tool with however I will bite the bullet and get one of those if this fails to work

[Jonny_H]

Just now, dannybgoode said:

Now isn’t that just the puppy! I’ve just bought a 3’ steel bar and some M4 bolts to make a suitable tool with however I will bite the bullet and get one of those if this fails to work

It's probably prudent to note that I haven't actually used mine on the mount yet (RA locking nut) but I assume that they will do the trick. It comes with 8 different sized pins and and I'm pretty sure one of them will fit the holes on the locking nut with no issue!

As mentioned though they have saved me in a few other situations already.

[dannybgoode]

Just now, Jonny_H said:

It's probably prudent to note that I haven't actually used mine on the mount yet (RA locking nut) but I assume that they will do the trick. It comes with 8 different sized pins and and I'm pretty sure one of them will fit the holes on the locking nut with no issue!

As mentioned though they have saved me in a few other situations already.

I’ve just had a quick look and there are a number of such tools. It’s just whether it is long enough and with a grip that you can get enough torque in to undo it.

It does look highly promising though so if my McGuyver effort doesn’t work I’ll give one a go :)

[chaxastro]

13 hours ago, dannybgoode said:

"I have tried making a tool by screwing some bolts through a piece of wood but the damned thing will still not budge.  Not sure what to do now!"

Try pouring boiling water (from a kettle) over then nut, give it a few seconds, then try to loosen the nut again. Have found this method to work in the past.

Or... freeze the shaft, but that not really going to help in this situation as its buried in the casting and you cant get at it.

Also, wear some gloves to protect your hands, you don't want to scold yourself!

Regards,

Chaxastro

"Humour is reason gone mad" Grouch Marx

[dannybgoode]

6 hours ago, chaxastro said:

Try pouring boiling water (from a kettle) over then nut, give it a few seconds, then try to loosen the nut again. Have found this method to work in the past.

Or... freeze the shaft, but that not really going to help in this situation as its buried in the casting and you cant get at it.

Also, wear some gloves to protect your hands, you don't want to scold yourself!

Regards,

Chaxastro

"Humour is reason gone mad" Grouch Marx

Trouble is the nut is still very much part of the mount water would possibly get to the control board etc.

I am going to try some WD40 and plug up any holes with kitchen paper as a first point of call see if that helps

[malc-c]

Remove the control board... 

If you have a nut stuck, heat is typically the only way to uncrack it.  Remove the electronics, and get a blow torch, or an electric heat gun used for paint stripping out and warm the nut up.

[dannybgoode]

Woohoo - RA locking nut finally undone.  One of these did the trick together with a good wallop with a Clarkson :).  The clutch plate was welded onto the RA mechanism though and has been slightly damaged removing it.  I think it will still be fine for now but does anyone know where to get a replacement?

I will not be tightening up the RA locknut nearly as much this time round so dismantling in the future will be much more simple

Laser LAS5281 Tools Adjustable Pin Wrench : Amazon.co.uk: DIY & Tools

[dannybgoode]

@Jonny_H - the small bearing is a 60mm outer/41mm inner and 4mm thick,  The large one is 90mm outer, 66mm inner and 4mm thick :).  The holes in the locknut are 4.5mm - a 4mm pin fits them nicely.  

[dannybgoode]

All done  . Need to get my tripod in so I can test it all indoors, get the backlash tuned etc and make sure it is all working in time for 2025 when there might be a cloud free night...

[Jonny_H]

3 hours ago, dannybgoode said:

@Jonny_H - the small bearing is a 60mm outer/41mm inner and 4mm thick,  The large one is 90mm outer, 66mm inner and 4mm thick :).  The holes in the locknut are 4.5mm - a 4mm pin fits them nicely.  

Thanks @dannybgoode 

I've also tracked down the size of the worm shaft bearings too! These are allegedly 608 2Z (I believe these are the metal cover ones).

That's all of them bar the needle roller bearings which are press fitted into either end of both RA and Dec housing. It seems though that these are best left untouched apart from a clean and regrease.

[dannybgoode]

Just now, Jonny_H said:

Thanks @dannybgoode 

I've also tracked down the size of the worm shaft bearings too! These are allegedly 608 2Z (I believe these are the metal cover ones).

That's all of them bar the needle roller bearings which are press fitted into either end of both RA and Dec housing. It seems though that these are best left untouched apart from a clean and regrease.

My mount is so lightly used it didn't seem worth changing any of the bearings at this point but it is nice to have cleaned all the old grease out, free everything up, loosen that damned locking nut etc!

And apart from that little hurdle the whole process is very simple, much easier than I thought it would be and next time I do it I may replace the bearings also.  Will be interesting to see if it does run better now...

[Jonny_H]

5 hours ago, dannybgoode said:

The clutch plate was welded onto the RA mechanism though and has been slightly damaged removing it.  I think it will still be fine for now but does anyone know where to get a replacement?

I would be inclined to email Optical Vision as a starting point. They helped me out in the past with some spare parts. They may ask for some photos of the part you are after etc...

[dannybgoode]

Well the good news is, it all seems to be working and certainly sounds very smooth.  Certainly a shade quieter than it was before also so hopefully the effort will have been worth it.  Can't wait to try it out now and see what the guiding looks like etc

[The_Bluester]

A comment on the needle roller bearings on the shafts to reply to a post a while back. You can't replace them with a tapered bearing like is used in an EQ6 as the clutch design on the AZEQ6 is totally different. In the AZEQ6 the clutch is under the head of the shafts and doing the clutch up pulls the shaft (RA or Dec) through those bearings to pull the shaft down and put pressure on the clutch disc to engage it.

That leads to my other suggestion, when you dummy assemble it, tighten the clutches down and check the clearance between the setting circles and housings. The RA clutch disc compressed over time on my mount (Orion Atlas AZEQ6 clone) and eventually the RA setting circle started fouling on the fixed RA housing and dragging, eventually it stopped it tracking. Once it gets like that the only fix is to replace the clutch friction pad to restore the clearance as the more you try to tighten the clutch the harder the setting circle drags. I cur 0.5mm thick aluminium packer discs and added them under the clutch discs to restore clearance as mine failed over the Christmas period a couple of years ago and I would have been waiting weeks for parts. It is still set up that way now and working perfectly. 

The other effect of that clutch design I have found is the payload sits on them which makes them drag, so balancing is tricky. I rotate mine counterweights up which releases the Dec clutch for balancing, but RA is harder, all you can do there is adjust the mount altitude as low as it goes to get as much weight off the clutch as possible.

[dannybgoode]

So the big question - was it worth it?! Well, I’ve used my mount for a good 10 hours now and at first it was a bit lumpy but now the grease gas had chance to work in and bed down I am getting sub-arc second guiding most of the time.

There are a couple of positions where it hovers around a second but mainly in the Dec axis and that, I think, simple I cannot balance the Dec properly at the moment as the saddle is too short for my rather back heavy scope in imaging guise.

Backlash needed a little fettle also - I had everything a shade tight but now everything looks really good.

I have the ADM replacement saddle on order though and that will solve this little issue.

Overall well worth doing and I’ll replace the bearings in a year it two but see no pressing need given how well it’s working now.

[david_taurus83]

Does it feel much looser now when the clutches are undone and your trying to balance? Mine is stiff brand new out of the box so balance is a bit of a guessing game.

[Stardust]

This all sounds good  getting frustrated with mine and thinking it needs this treatment.  ra is very stiff, dec is very free.

If seen a reports of superlube or the bicycle grease, so which is best for this mount?

 

[dannybgoode]

On 13/01/2022 at 08:37, Stardust said:

This all sounds good  getting frustrated with mine and thinking it needs this treatment.  ra is very stiff, dec is very free.

If seen a reports of superlube or the bicycle grease, so which is best for this mount?

 

This seems to be the recommended stuff. Has worked well on mine…

https://www.amazon.co.uk/dp/B01186U64Y/ref=cm_sw_em_r_mt_dp_DFEPCKNBZ9PXN4AHE692?_encoding=UTF8&psc=1

[Stardust]

All went well today, the video you linked was very helpful. everything is much better now apart from one of the RA worm bearings is grindy and needs replacing. It's a 608Z, anyone a link for replacements or a SKF number.

I don't mind that it's still in bits as it should be a much better mount once finished

 

[Starflyer]

I've used both SKF and skate bearings in the past, the skate bearings perform better, look for ABEC 7 or 9, something like this will be super smooth.

[Skipper Billy]

17 hours ago, Stardust said:

one of the RA worm bearings is grindy and needs replacing. It's a 608Z, anyone a link for replacements or a SKF number.

https://simplybearings.co.uk/shop/advanced_search_result.php?keywords=608z&gclid=Cj0KCQiAoY-PBhCNARIsABcz772jCszCDMBxJxMF0F2C6KbyI47RoqrfXQyClLC_pMYquE69HdRyZjgaAqnaEALw_wcB&

 

Usually next day delivery

[Stardust]

10 hours ago, Skipper Billy said:

https://simplybearings.co.uk/shop/advanced_search_result.php?keywords=608z&gclid=Cj0KCQiAoY-PBhCNARIsABcz772jCszCDMBxJxMF0F2C6KbyI47RoqrfXQyClLC_pMYquE69HdRyZjgaAqnaEALw_wcB&

 

Usually next day delivery

that's great thanks, ordered. One of the RA collar grub screw threads was stripped, so drilled & tapped to 5mm, box of grub screws ordered. This must have been at the factory as I've had the mount from new and the first time it's been apart

[Stardust]

Pleased to report it was all a great success. Lee came round for the fun of ripping my mount apart. Clutch plates were stuck, worm wheel was too tight on the shaft, one worm end bearing shot, had to drill and tap the grub screws to 5mm. Very pleased with the initial guiding tests, The RA axis looked more like rough saw tooth but is pretty good now. TBH I think the mount is better than when it was new, don't think I ever got tracking this good. It wasn't very hard following the video, good job all round.