EQ6 Mount, dismantling and maybe timing belt?

[Astrofriend]

Hi,
My EQ6 mount is old now. Very stiff RA and DEC axis, it's time to dismantle it and see how bad the inside is.

I followed the Astro Baby guide and it was not any big problem to dismantle it. It looks fine inside, I suspect some earlier owner already have done this cleaning and put new grease on. But that must be years ago.

When I now have dismantled everything, shall I rebuilt it and install timing belt drives? I feel it's a little to much money to put on this old mount. I have to think about it and see what alternatives there are.

Here is my EQ6 dismantling story:
http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/01-eq6-dismantling-rebuilding.html

Only first part, now I'm drawing plans.

/Lars

[Astrofriend]

Now when the mount is clean and I had some time think about the what I can do. Whatever rebuilt of the mount need some machines and tlls I don't have. That's life when living in a flat.

 

I have listed four different ways how to proceed, I have it written down on the homepage:

http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/02-eq6-dismantling-rebuilding.html

 

First I will give the original spur gear a chance, if it fail I will continue with some other solution.

 

/Lars

 

[Astrofriend]

Hi,
Now I have ordered timing pulleys, I choosed a 60 teeth pulley with no flange and a 16 teeth pulley, it gives a non standard 3.75:1 ratio. Small pitch, wider belt and bigger pulleys should give a bit less elastic and smoother run compare to the normal kits, at least according to my ideas and help from forums. But I can not use the handterminal with this non standard gear ratio, but I never do that anyway.

I bought them at https://www.active-robots.com/ in Great Britian because I live in Europe Union and then I don't have to pay custom fees and taxes. They was one of few that could offer the 60 teeth pulley with a 12 mm diameter bore.

I have done some updates and put in more links with information:

http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/01-eq6-dismantling-rebuilding.html

At page three there is a link to a belt length calculator.

/Lars

[Astrofriend]

Now I got the timing belts and pulleys from GB. Looks great but maybe needs a little bit more work then I expected.

 

Here are the new parts and how it looks:

http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/04-eq6-dismantling-rebuilding.html

 

/Lars

 

[spillage]

I installed the standard belt drive into my old neq6 and have never looked back. Easy to fit, quiet and much better tracking.

[Astrofriend]

It's always so much to do, but this weekend I got some time to work on my EQ6 mount.

I have removed the paint on the surfaces of the lids that cover the worm gear.

You can follow the work here:
http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/05-eq6-dismantling-rebuilding.html

I have also got the steel shims I ordered, but only got half of the number I ordered.

/Lars

Edited June 16, 2019 by Astrofriend

[Rusted]

Glue some fine sandpaper or fine emery paper to a flat piece of plywood or thick piece of glass.

Then smooth and flatten the surfaces using short strokes.

[Nigella Bryant]

On 21/05/2019 at 23:34, spillage said:

I installed the standard belt drive into my old neq6 and have never looked back. Easy to fit, quiet and much better tracking.

Me too, best thing for an old neq6/eq6 is to do the belt mod. Made a huge difference in smotheness and tracking. 

[Astrofriend]

Now it's time for an update of my timing belt project.

From the beginning I was not convinced that I should modify my EQ6 mount and replacing the spur gears with timing belts. But I do now.

I needed some tools and machines.

I looked for a used desktop lathe but couldn't find any and the time goes on. Later a new friend offer to me to use his lathe, perfect, maybe I can be finished in time and some test later when the darkness comes back.

You can read here what I have done, also added a lot of photos to make it easier to follow:

http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/06-eq6-dismantling-rebuilding.html

I can not recommend any to do this, better to buy a ready made kit that is just to mount. I feel it's more exiting to do things myself, maybe a sickness.

It will be very interesting to see if I get any advanteges of using a wider 6 mm belt for more stiffness and the GT2 profile pulleys that they use in 3D printers to reduce the backlash.

/Lars

[Rusted]

Just a couple of points. A wider and longer, fine, flat file is the best way to get flat surfaces.
Don't hold the handle. Let the file flatten itself by pressing gently on the middle of the file itself.
If the file bridges spaced surfaces it is automatically held flat by both surfaces.
A larger, smooth file rides over hollows but still takes downs "the hills."

I have made new grub screw holes and threaded them in timing pulley hubs.
I usually make three holes for three new screws at 120° apart around the hub.
This is easy with a lathe because you can use the 3-jaw chuck to mark the hub.
A small sharp tool is run along the hub while suitably tall packing pieces are placed under each chuck jaw in turn.
Turn off the power to the lathe beforehand!

Three radial screws helps to avoid forcing the pulley off-center. [i.e. Becoming eccentric.]
It is important NOT to drill the fresh holes too large for the thread cutting tap.
Taps will often cut oversize if you go all the way through.
I use paraffin [lamp oil] as a cutting lubricant on aluminium.

Stop short of tapping right through and you can arrange the screw to almost bind in the newly threaded hole.
This gives you a gentle locking action to avoid the grub screws undoing themselves over time.
It would be a disaster if the loosened screws jams or even causes damage to the casting.
Particularly if you you had to dismantle the mounting!
Blue thread locking fluid might be a good idea. NOT red if you ever want to remove the screws again.

[Astrofriend]

At last, I could start assembling the EQ6 mount.

 

This first step was easy, only installed the timing pulleys, the big one ocn the worm gear drive.

 

Here it is:

http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/07-eq6-dismantling-rebuilding.html

 

I will be busy with a star party the following days, after that I shall take next assembling, how to get the timing belt correct installed between the two timing pulleys. Looks very difficult.

 

/Lars

[Astrofriend]

Today I have assembling more items on the EQ6 mount. I have measure the needed thickness of the RA and DEC shafts shims. I also checked if the length of the timing belts are correct, almost but have to do some modifications of the brackets for the stepper motors.

Here is photo and info of todays work on the EQ6 mount:
http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/08-eq6-dismantling-rebuilding.html

/Lars

Edited September 16, 2019 by Astrofriend

[Astrofriend]

The mount is now assembled again and I can start to do some test and adjustings.

I noticed that I had some friction when the clutches where open, didn't expect that. After some examination and test I found what happens in the mount and cause the friction.

It's only when the cluthes are open I have friction. When closed and tracking it rotates with the two other roller bearings and then it's almost no friction. Good!

Some photos from when I testing this:
http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/12-eq6-dismantling-rebuilding.html

For me it had been better without these clutches, less complicated and more compact, save some kg also.

If I ever build my own mount it shall not have any clutches and no gearboxes. It shall have direct driven 3-phases DC motors. For the moment only a dream.

Until then I collect information:
http://www.astrofriend.eu/links/links-astronomy-directdrivemount.html

/Lars

Edited September 23, 2019 by Astrofriend

[Astrofriend]

Now at last, I could power up the EQ6 mount again.

Really exiting to do this first test. One important thing was to setup the EQMOD with custom gear ratios, never done it before. It looks to work with the indoors test I did.

Here it is:
http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/13-eq6-dismantling-rebuilding.html

To my surprise the sound / noise was almost as high as before. Maybe others with standard spur gear has very high noise.

I hope we get a clear sky soon so I can do real test.

/Lars

[Astrofriend]

After a long delay I could do some test of the modified EQ6 mount with the new belt drive.

I use PHD2 but have not optimized the parameters yet, even that I could get a tot rms error of 0.69"

 

I have some screen dump with graphs here:

http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/18-eq6-dismantling-rebuilding.html

 

I'm not sure if the EQMOD and PHD2 is at its optimum setup, earlier I had an off-axis adapter and I got less tot rms error but the field was very limited.

 

/Lars

Edited January 9, 2020 by Astrofriend

[Astrofriend]

My EQ6 projects continue forever.

I had a lot of problems with the hardware driver in the EQ6 mount. There is some bug in the driver I had understand, that's why there is a RA drift compensation in EQMOD. With my custom gear ratio this problem got worse. Now I decided to replace the original driver with an external driver. I already have an AstroEQ driver that I want to test.

I need some space where to place it, I have here started 3D-print a new lid for the EQ6 mount:

http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/20-eq6-dismantling-rebuilding.html

I have also ordered some connectors and cables to make adaptercables between the RJ11 6/4 to the JST connector that the stepper motors have.

/Lars

[Astrofriend]

Now at last I can control my EQ6 mount with custom gear ratio from EQMOD Indi version which I use with my Raspberry computer. Lot of work and lot of help to modify the Indi driver to accept custom gear ratio.

Here is some instruction how I made it:
http://www.astrofriend.eu/astronomy/projects/project-indi-drivers/01-project-indi-driver.html

Note: The gear ratio must be setup for one fixed custom gear ratio. It's done in the source code as it's now.

The driver can distinguish between an EQ6 mount with custom gear ratio and a HEQ5 with standard gear ratio. I use the same control computer for both mounts.

Lars

[Astrofriend]

When looking at my old projects I noticed that I have a lot of readers on my project about the EQ6 mount. I have gone through the text and correct mistakes and moved out some of the pages to separate projects/tutorials.

Here is the updated version:
http://www.astrofriend.eu/astronomy/projects/project-eq6-dismantling-rebuilding/01-eq6-dismantling-rebuilding.html

Let me know if there is something that is unclear and I try to complement the information.

It works very well nowadays, both on Windows ASCOM and Linux KStar system.

Lars