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AZ-EQ6 lower DEC bearing

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#1 cdh79

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Posted 19 April 2016 - 04:45 AM

Hello,

 

I have removed the DEC axis on my AZ-EQ6 and found that the bearing on the lower side of the housing has very rough edges, and there were quite a few metal scrapes that i removed with the grease.

 

When looking at this image below, i wonder if the second ring is the outer casing of the bearing and if this would be removable, as it doesn't seem to move at all?

It does look different than on the EQ6 (not AZ) as this is a cone bearing, but here the rolls seem straight.

 

 

Attached Thumbnails

  • bearing.jpg

Edited by cdh79, 19 April 2016 - 04:45 AM.


#2 Ultron

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Posted 19 April 2016 - 07:18 AM

That bearing looks like it is press fitted.  You might be able to tap it out lightly using a mallet and something that has an end the same diameter as the bearing, maybe the handle of a screwdriver?  Do you have a pic of the inside from the top end of the DEC axis?



#3 EFT

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Posted 19 April 2016 - 10:47 PM

The roller bearing that is in there is usually nearly impossible to get out because the seat on the other side does not allow you to either place something on the outer race from the other side and tap the bearing out or get some kind of bearing puller in there to pull the bearing out.  These are completely different than the EQ6.  In general, the best you can do, without damaging the bearing is clean it out as best you can in place.

 

Now which part of the bearing are you seeing as rough? The inner cage for the rollers?



#4 olivdeso

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Posted 19 April 2016 - 11:42 PM

Heat the mount around the bearing using hot air.

 

The allumininium thermal expansion coefficient is greater than the steel one.

The bearing will be much easier to remove.

 

When you fit the new bearing, cool the bearing in a congelator and heat the mount using hot air. Add a very thin layer of grease onto the mount


Edited by olivdeso, 19 April 2016 - 11:43 PM.


#5 cdh79

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Posted 20 April 2016 - 04:30 AM

thanks for your comments.. i will try to make more images once I get home from work today.

 

Ed, yes the most inner ring/cage that holds the individual rollers is the one that's roughed up (and most likely the cause of the metal scrapes i cleaned out).. I will try to make a close-up on this as well

 

thanks,

Chris



#6 cdh79

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Posted 20 April 2016 - 06:24 AM

After having done a bit more searching it seems that these bearings are "NK 40/20 TN" and therefor the cage does belong to the bearing..

 

thanks olivdeso for the advice with warming/cooling, i will look into this if i decide to replace this bearing



#7 cdh79

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Posted 21 April 2016 - 01:56 AM

Here are the images i promised..

 

I don't have a macro-lens, so it's still a bit tricky to image this well, but on the first two images you can see the cage that holds the rollers not having a square edge, but it looks like something touched/shaved off the corners. I think it's best to see by the different reflections of the light.

 

Looking at the play of the rollers it doesn't really seem to be causing any actual impact, so I will not replace this bearing, as it seems to be a bit tricky to get it out.

I also attached an image of how the inside looks like from the other side.

 

The worm gear housing had quite a lot of paint, so i have cleaned this off right away.

I have also ordered SKF bearings for the worm-shaft, so i will replace those.

Can anybody please give me a pointer on how to best remove the RA shaft?

I know to first remove the polar scope, then I removed the "pointer", and I am aware that there are 3 grub screws that have to be loosened/removed through the holes of the RA clutch.

 

That's basically where I am stuck now, as i don't know how to best remove this assembly then.

I understand on the regular EQ6 it's best to use an oil-filter-extractor, would this be the same on the AZ?  can you mount one of those with the silver ring of the clutch still being in the way, or can this clutch-ring be removed individually?

 

thanks!

Chris

Attached Thumbnails

  • edge.jpg
  • edge2.jpg
  • inside.jpg

Edited by cdh79, 21 April 2016 - 02:06 AM.


#8 scopenitout

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Posted 21 April 2016 - 10:57 AM

Those pictures look nasty!

Here's my take....

Because the bearing is an interference fit, and the casting bore is poorly machined (if at all), Wing Loong took the expedient path and smashed it in with a hammer.

Besides that, tea break was just around the corner and he didn't want to miss it.



#9 EFT

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Posted 21 April 2016 - 11:55 AM

That is certainly not a very good looking bearing.  It looks like it was hammered into place damaging the cage.  That's the problem with this type of bearing.  Now if it turns freely, it is probably OK but the metal shaving are a concern.  The problem is getting it out.  You would need to use a long metal rod to tap it out from the other side but since you will be tapping on the cage rather than the out race, that bearing will be a write-off.  More problematic though is the fact that the cage and rollers might pop out leaving the outer race in place and very difficult to remove.  Refrigerating the assembly is worth a try to see if it loosens thing enough to push that bearing out, but its hard to say if it will.  The same problem occurs with the Losmandy mounts where I find that some bearings simply can't be removed no matter what I do and they have to be left in place and cleaned in place.  Of course, if you get the old bearing out, you will have to get the new one in and that will also be a challenge, especially with out a press. 

 

Taking the RA apart is challenging.  There are some grub screws underneath the clutch that have to be loosened (you can see them through the holes in the clutch ring) so that the axis retaining ring can be removed which is going to require some kind of spanner.  An oil filter wrench will be of no help here.



#10 cdh79

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Posted 21 April 2016 - 12:25 PM

that someone might have hammered this bearing in was also my first thought.. i think i'll leave it in place and check what's the best to get any shavings out..

 

thanks for the info on the RA axis Ed.  I did see and remove the 3 grub screws underneath the clutch, but I wasn't aware if I then should be able to just pull it out, or if it needs to be screwed off somehow without locking the clutch.. looking at your comment that I would need a spanner of some sort makes me think that pulling should then be sufficient.

 

I just replaced the DEC worm-axis-bearings and will have a look how it performs after tightening up the backlash a bit and then decide if I try to find something that i could pull the retaining ring off to swap the RA bearings as well..

 

anyways, thanks a lot for your help, it is highly appreciated!


Edited by cdh79, 21 April 2016 - 12:26 PM.


#11 EFT

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Posted 21 April 2016 - 07:35 PM

If you remove the electronics panel, the best way to clean as much as possible out of the bearing will be to wipe it down first.  Then use compressed air to blow it out as much as possible.  Wipe it down again and apply some new lubricant (I recommend SuperLube).  Work the new lube in and go through the same process again.  That will remove as much of the old lubricant and metal particles as possible without removing the bearing from the housing.

 

The retaining ring underneath the RA clutch unthreads from the axis shaft.  Once you get it going it is not usually to hard to get off.

 

The retaining ring for the worms can be a real pain depending on how much thread lock they used in there.  If there isn't much, then a flat blade screwdriver might be sufficient to unthread the ring, but if there is a lot (fairly typical) then a spanner will be necessary.  I have never been able to find an off-the shelf spanner to do that and need to have them made instead.



#12 cdh79

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Posted 22 April 2016 - 08:28 AM

thanks Ed, that was the invaluable tip!

 

What I did was - after removing the 3 grub screws from the retaining ring under the clutch, i just placed the top of an allen key inside one of the 3 holes and put some cloth against the side of the mount.. then I turned the mount head, so that the allen key would get "stuck" on the side wall (where the cloth was to not damage the paint) to give it the initial "spin" and after that this black ring was easily screwed out..

 

i think a picture is more helpful than me trying to explain ;)

 

 

i have also made pictures of all my steps so far, so i think for simplicity for other people, I will upload them somewhere as a guide..

 

thanks again, now i can replace the RA worm-shaft bearings and thanks to one of your other posts I had already bought superlube yesterday  :)

Attached Thumbnails

  • ring.jpg

Edited by cdh79, 22 April 2016 - 08:29 AM.


#13 scopenitout

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Posted 22 April 2016 - 02:51 PM

thanks Ed, that was the invaluable tip!

 

What I did was - after removing the 3 grub screws from the retaining ring under the clutch, i just placed the top of an allen key inside one of the 3 holes and put some cloth against the side of the mount.. then I turned the mount head, so that the allen key would get "stuck" on the side wall (where the cloth was to not damage the paint) to give it the initial "spin" and after that this black ring was easily screwed out..

 

i think a picture is more helpful than me trying to explain ;)

 

 

i have also made pictures of all my steps so far, so i think for simplicity for other people, I will upload them somewhere as a guide..

 

thanks again, now i can replace the RA worm-shaft bearings and thanks to one of your other posts I had already bought superlube yesterday   :)

 

Chris,

 

I have an AZEQ-6 I use as my spare. It is a friction-filled mess and I would like some expert instructions before I open it up.

Please do publish an illustrated guide for dismantling the AZEQ-6.

There are legions of owners who would be very grateful for your effort.

 

As far as I know there is only the "Astrobaby" guide for the EQ-6.

That is not entirely suitable for the AZEQ-6 as it is assembled differently.



#14 EFT

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Posted 22 April 2016 - 06:06 PM

Except for the worm spacing adjustment, the mount is completely different from an EQ6.  Thankfully, it is only slightly more complicated though.  I really need to work a video for that one.  The thing is, there is actually less than can be improved on the AZEQ6 than on the EQ6.  This is because there are actually far less friction faces that can be improved and the worst one is the one you can do nothing about, the clutch face.  Because the mounts use a clutch system very similar to the Losmandy mounts where the clutch is "engaged" by tightening a threaded ring that pulls the entire axis shaft tighter to allow the clutch pad to stop movement, there is very little that can be done to free up the axes.  Some mounts improve better than others simply by cleaning out the over abundance of grease elsewhere in the mount, but there is a definite limit as to how freely you an get the axes to turn and still have functional clutches.  It is really a design change that I don't think was for the better.  With a standard EQ6 you get things to where it is very easy to do a good job of balancing the mount.  That's really not the case with the AZEQ6, so before you tear into it, think about whether that is all you are trying to accomplish.  If it is, you may just want to leave it as is.  If, on the other hand, you are looking to clean out the original grease and put in better worm bearings and make more proper adjustments in order to improve overall performance, then there are improvements you can accomplish.



#15 scopenitout

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Posted 22 April 2016 - 07:01 PM

A detailed video would be great, Ed, as would some sharp images of the disassembly / assembly sequence (Chris??).

After reading Ed's explanation of the clutch system, I now understand why mine is so stiff.

While I'm in no hurry to get inside of it (I also have a Paramount), after seeing the carnage inside of Chris' AZEQ-6, I think I'd like to have a look.



#16 cdh79

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Posted 23 April 2016 - 05:46 AM

I had noticed with my mount that i could turn the DEC pretty freely when turning the head in counter-clockwise direction, but it would "tense up" when i turned it in clockwise direction.
Given the explanation of the clutch and that it's just a "screw-in" design this now fully makes sense to me.
What i did notice is that i could then easily just push the shaft back up a bit to loosen it again once this friction happened in the DEC.
Prior to balancing I now just turn he DEC a few times counter-clockwise to make sure it's loose.

I am out of the country for the weekend, but once I'm back home I'll continue cleaning the RA and will post the pictures I have taken from disassembling.
Not to say that I'm an expert with this mount (far from it), but at least by now having taken the DEC apart a few times and having now gotten past the (to me) more confusing part of the RA I believe to understand most of this mount.

Seeing images of what has worked for me will surely be useful for others as well.

#17 cdh79

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Posted 26 April 2016 - 01:23 PM

ok, here as promised some images of the disassembly.

 

This is what has worked for me, and I'm in no means an expert, so please do at your own risk..

Also these images are made during multiple different disassembly/assembly attempts, so don't be surprised that in some images some parts are actually still mounted even though I disassembled them at an earlier stage.

 

Also I have not removed the motor-cover to the electrics so far, so this is not shown.

 

 

I first started out by removing the screw at the end of the weight-shaft.

Next i loosened three grub screws in the nut beneath DEC clutch.  Once this was done the nut, as well as the clutch could easily be unscrewed.

Watch out for the metal washer and bearing that will most likely fall come out with the clutch.

 

There are always 2 washers next to these sort of bearings, so if (just as in this case) only one comes out, the other one will be stuck to the inside as shown on the last pic

Attached Thumbnails

  • 2016-04-20 16.42.38.jpg
  • 2016-04-20 16.43.20.jpg
  • 2016-04-20 16.44.44.jpg
  • 2016-04-20 16.46.18.jpg
  • 2016-04-20 16.46.28.jpg

Edited by cdh79, 26 April 2016 - 01:31 PM.


#18 cdh79

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Posted 26 April 2016 - 01:23 PM

once that was done, i removed the mounting plate by loosening the 3 grub screws there.. 

after the removal it was easy to push the counterweight shaft out through the top..

the next step for me was to loosen the two grub screw that move the DEC worm gear housing (which are also used to adjust backlash) 

then i removed the top part with the shaft, by lightly hitting the shaft with my hand.. i would recommend using a rubber mullet for this

Attached Thumbnails

  • 2016-04-20 16.46.36.jpg
  • 2016-04-20 16.47.09.jpg
  • 2016-04-20 16.47.34.jpg
  • 2016-04-20 16.47.38.jpg
  • 2016-04-20 16.48.14.jpg

Edited by cdh79, 26 April 2016 - 02:30 PM.


#19 cdh79

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Posted 26 April 2016 - 01:23 PM

i next removed the soft washer and you can see the worm gear underneath, which i then removed..

here again you will find two washers and a bearing in the middle..

 

then i took off these big screws that keep the housing in place.. I did notice that I should have first done some other steps like taking off the side-plate..

Attached Thumbnails

  • 2016-04-20 16.48.31.jpg
  • 2016-04-20 16.49.07.jpg
  • 2016-04-20 16.49.11.jpg
  • 2016-04-20 16.52.00.jpg

Edited by cdh79, 26 April 2016 - 01:42 PM.


#20 cdh79

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Posted 26 April 2016 - 01:24 PM

..so that's what i did in the next step.

remove the side housing as well as the cover of the encoders, so i could remove the belt as well as the little cable that connects to the encoder..

 

once these had been removed, i could take the worm gear housing off and was quite surprised about the amount of paint on the surface (this i cleaned off before reassembling the mount again)

Attached Thumbnails

  • 2016-04-20 16.53.48.jpg
  • 2016-04-20 16.55.35.jpg
  • 2016-04-20 16.56.24.jpg
  • 2016-04-20 16.59.01.jpg
  • 2016-04-20 16.59.46.jpg

Edited by cdh79, 26 April 2016 - 01:45 PM.


#21 cdh79

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Posted 26 April 2016 - 01:24 PM

next I hopened up the cover using some pliers that fit inside these two holes..

underneath was a retaining screw (i think that's what they're called) with two small slots on each side (we'll come by one of those on the RA side as well) and it was quite a pain to get them to remove..

eventually i managed by using a larger screwdriver..

on the other side are two grub screws that hold the wheel in place.. notice that one of these grub screws is against the flat part of the worm axis, for putting it back together..

 

once this is out you can remove the worm axis and the worm-bearings (which i have replaced with SKF 608-2Z in my case.. those are the same as 608-2rs but instead of rubber shielding have a metal shielding on both sides)

Attached Thumbnails

  • 2016-04-20 17.03.31.jpg
  • 2016-04-20 17.03.39.jpg
  • 2016-04-20 17.04.07.jpg
  • 2016-04-20 17.10.34.jpg
  • 2016-04-20 17.11.15.jpg

Edited by cdh79, 26 April 2016 - 01:52 PM.


#22 cdh79

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Posted 26 April 2016 - 01:24 PM

more images of removing the DEC bearings and finally the DEC worm-gear housing fully taken apart and ready for degreasing and cleaning and reassembly by following these steps backwards..

 

for adjusting the wobble/backlash I used the guide from Astro-baby for the EQ6 as this works the same way (so i will not go into detail here)

Attached Thumbnails

  • 2016-04-20 17.11.44.jpg
  • 2016-04-20 17.15.55.jpg

Edited by cdh79, 26 April 2016 - 01:57 PM.


#23 cdh79

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Posted 26 April 2016 - 01:24 PM

for the RA (please note that this was done on another day, so if you followed the disassembly above some parts will already have been removed) I first removed the polar scope by simply unscrewing it by hand..

 

next, there are 3 grub screws inside the black retaining nut at the bottom underneath the clutch, so get an allen-key and turn the RA until you can see and loosen/remove these grub screws..

once that was done i removed the pointer for the polar scope dial..

 

I then loosened up the two grub screws opposite of each other on the RA that are used to adjust backlash and removed the belt from the wheel via the side..

i also loosened the big allen-screws that connect the housing a bit

Attached Thumbnails

  • 2016-04-20 18.16.43.jpg
  • 2016-04-20 18.28.22.jpg
  • 2016-04-20 18.49.35.jpg
  • 2016-04-20 18.50.48.jpg
  • 2016-04-20 18.50.51.jpg

Edited by cdh79, 26 April 2016 - 02:33 PM.


#24 cdh79

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Posted 26 April 2016 - 01:24 PM

my next step was to remove the retaining nut at the clutch.. to do this i inserted the top of an allen wrench through the clutch into one of the holes of the 3 grub screws that have been loosened/removed earlier..

I placed some cloth against the side-wall and jammed the allen wrench lightly against the side-wall by rotating the RA axis.. just a very light push was needed and the black retaining nut underneath the clutch could be unscrewed.. 

here again was a washer-bearing-washer combination..

 

once this was done i pulled out the mount-head of the RA housing and put it on a towel.. as you can see in this image the DEC part is fully mounted, as these images were taken during another disassembly..

 

Attached Thumbnails

  • 2016-04-22 15.14.35.jpg
  • 2016-04-22 15.32.12.jpg
  • 2016-04-22 15.32.36.jpg
  • 2016-04-22 15.32.28.jpg

Edited by cdh79, 26 April 2016 - 02:14 PM.


#25 cdh79

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Posted 26 April 2016 - 01:25 PM

next i removed the encoder-cover and made sure that the grub screws for adjusting the RA worm-gear housing were really loose enough..

after unclipping the encoder-cable i opened up the big screws that mount the housing to the mount, but be careful.. at this point I recommend to open up the second side-cover that contains the switches, motors etc., as there is yet another encoder connected to the RA worm-gear housing from underneath!   I wasn't aware of that and fortunately the cable didn't break, but just detached regularly.. 

Attached Thumbnails

  • 2016-04-25 19.26.30.jpg
  • 2016-04-25 19.27.42.jpg
  • 2016-04-25 19.29.15.jpg
  • 2016-04-25 19.32.55.jpg

Edited by cdh79, 26 April 2016 - 02:20 PM.



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