No Shims required case

[Ali Alhawas]

Hi,

 

I am working now on replacing all the mount bearings and lubricate parts.
When I calculate the shims requirements as Astro-Baby recommended, I ended up with:
No shims required in the Dec. axis,, My question is:
Is it normal to place the worm gear on its place without any thing between? See the pictures please.
In addition, when doing this and rotate the worm gear by hand it produces a sound like metal friction.
I think the worm gear edge is contact with the casing itself.
So, what do you do if you face this issue?

Mount: Orion Atlas eq-g the same as EQ-6

Bearings: SKF 6008 2RSH in this case.

 

Thanks
Ali

[Same old newbie alert]

Use the thinnest teflon washer you can find

What's the calculation, not familiar with astrobabys recommendations

Edited February 12, 2022 by Same old newbie alert
Added info

[Dr_Ju_ju]

Look for a "shim washer" stainless steel, teflon, nylon etc. (I personally use stainless) measuring the inside diameter and outside diameter... standard ones can be found as thin as 0.1 mm  ...  

[Same old newbie alert]

25 minutes ago, Dr_Ju_ju said:

Look for a "shim washer" stainless steel, teflon, nylon etc. (I personally use stainless) measuring the inside diameter and outside diameter... standard ones can be found as thin as 0.1 mm  ...  

Or cut your own from teflon sheet

[Ali Alhawas]

17 hours ago, Same old newbie alert said:

Use the thinnest teflon washer you can find

What's the calculation, not familiar with astrobabys recommendations

I will .. but afraid of worm gears not align perfectly !  

Regarding astro-baby .. Here you can find it..

https://www.astro-baby.com/astrobaby/help/rebuilding-the-skywatcher-eq6orion-atlas-mount/supertune-the-eq6-addendum/

in the " Shim setting/calculations" section you can find how to get your correct size of the shim.

Edited February 13, 2022 by Ali Alhawas

[Ali Alhawas]

17 hours ago, Dr_Ju_ju said:

Look for a "shim washer" stainless steel, teflon, nylon etc. (I personally use stainless) measuring the inside diameter and outside diameter... standard ones can be found as thin as 0.1 mm  ...  

Thanks..

So, you agreed that I have to put a shim in there.. even with "no shims required" as calculations results ?!

[Same old newbie alert]

2 hours ago, Ali Alhawas said:

I will .. but afraid of worm gears not align perfectly !  

Regarding astro-baby .. Here you can find it..

https://www.astro-baby.com/astrobaby/help/rebuilding-the-skywatcher-eq6orion-atlas-mount/supertune-the-eq6-addendum/

in the " Shim setting/calculations" section you can find how to get your correct size of the shim.

What thickness washer/shim was in there originally, bet it was way bigger than 0.10 and made of plastic

[Ali Alhawas]

17 minutes ago, Same old newbie alert said:

What thickness washer/shim was in there originally, bet it was way bigger than 0.10 and made of plastic

Yep.. It was 0.5mm 🤪 and made things harder.. 

Hope the 0.1mm shim will work perfectly. 

[Same old newbie alert]

All it means is the worm and the ring gear won't be perfectly aligned

In that link you sent me the figure was in a negative figure, but still put a 0.1 shim in there

I think I have some teflon sheet somewhere, if I find it are you in the UK?

 

 

 

[Same old newbie alert]

My teflon sheet measures .2

I have some shims but they measure 0.3,0.45,.0.6

 

 

 

[Starflyer]

On 12/02/2022 at 11:23, Ali Alhawas said:

 

 

Is that bearing all the way in, it looks high in the casting to me? Maybe a tiny piece of swarf or other muck underneath it.

They're designed to need some shim, I've stripped and rebuilt a few and I've never seen or heard of one not needing a shim.  If it were me I'd pull that bearing out, check underneath it for crud / damage in the journal, if all looks good measure the bearing thickness against the old one.

[Ali Alhawas]

20 hours ago, Same old newbie alert said:

All it means is the worm and the ring gear won't be perfectly aligned

In that link you sent me the figure was in a negative figure, but still put a 0.1 shim in there

I think I have some teflon sheet somewhere, if I find it are you in the UK?

 

 

 

Oh, thanks for your kindness ..

I am in Saudi Arabia and have the same shims as you..

Actually the measurements gave 0.1mm shim So, I will put the smallest shim I have which is 0.25mm and see how it goes.

BR,

Ali

Edited February 14, 2022 by Ali Alhawas

[Ali Alhawas]

16 hours ago, Starflyer said:

Is that bearing all the way in, it looks high in the casting to me? Maybe a tiny piece of swarf or other muck underneath it.

They're designed to need some shim, I've stripped and rebuilt a few and I've never seen or heard of one not needing a shim.  If it were me I'd pull that bearing out, check underneath it for crud / damage in the journal, if all looks good measure the bearing thickness against the old one.

Thank you for your recommendations.

The bearings is surely all the way in.. maybe I have to measure the old and the new thickness.

All area under/around the bearings is clean and clear, I will recheck again anyway.

"They're designed to need some shim, I've stripped and rebuilt a few and I've never seen or heard of one not needing a shim" --> this made me happy and waiting for any one to confirm, and you did !

Mount parts are on the table now cleaned and greased and 12 New bearings are ready to installed .. . I am just waiting for the shims to receive in about 4-5 days.

Many thanks for your time and support.

 

BR,

Ali

 

[Starflyer]

Your welcome Ali, let us know how you get on with the rebuild.

[Ali Alhawas]

On 15/02/2022 at 00:38, Starflyer said:

Your welcome Ali, let us know how you get on with the rebuild.

Hello,

Long time due to parts delay..

Anyway.. rebuild is finished but not yet tested under sky..

Dec. stiffness gone..

I filed about 0.1mm from the case to get total shim required about 0.2mm.

rebuilding was smooth and straightforward.

Just waiting for guiding graph certificate  

Thanks all for your great support.

BR,

Ali