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Best grease for GEM?

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#1 nashtok

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Posted 23 February 2015 - 06:05 PM

Greetings,

 

Sometime before summer hits the Pacific Northwest (and thus clear skies), I'm planning on doing a teardown and rebuild of my EQ-5 mount.  After studying many guides and forum entries from lots of astronomy related sites, I'm scratching my head at what grease to use.  For the worm gears, I'm almost certainly using a white lithium grease, but I'm unsure about what to use for the actual bearing surfaces.  I've read that some people say use white lithium grease for all surfaces, but others say that is too thin and you need something thicker (but not as thick as the glue grease the manufacturers use).

 

Also, this may be a stupid question, but how does the worm gear turn each axis of a GEM?  I like to think that I'm at least competent at using these sorts of mounts, yet I've never really gotten how the rotation worm assembly affects the axis.  I get that a worm gear is an inherently one directional system and that the worm gear can never turn the worm, but is there just enough friction that the worm turns the axis, but the axis doesn't catch too much on the worm? 

 

Thanks!



#2 orlyandico

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Posted 23 February 2015 - 07:00 PM

Superlube.

#3 Adam Taylor

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Posted 23 February 2015 - 08:02 PM

I recently reassembled and readjusted my EQ-3.  I used Park Tool bicycle grease.  I think it's pretty good stuff.



#4 pbunn

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Posted 23 February 2015 - 08:34 PM

I second Superlube.



#5 orlyandico

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Posted 23 February 2015 - 09:20 PM

I've read many times that white lithium should not be used.  In my experience, the light oil dries out leaving the gritty powder stuff.  Not good.



#6 HowardK

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Posted 24 February 2015 - 01:31 AM

  • superlube


#7 otocycle

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Posted 24 February 2015 - 01:32 AM

Super Lube synthetic grease



#8 rmollise

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Posted 24 February 2015 - 08:18 AM

And very little of it. ;)



#9 nebultick

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Posted 24 February 2015 - 08:40 AM

I think the park tool bicycle grease is better than super lube. Park tool grease is thinner and slides better. 



#10 macdonjh

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Posted 24 February 2015 - 09:28 AM

I agree with orlyandico in not recommending white lithium grease.  I don't think it holds up well in the conditions a telescope mount finds itself.  I use Mobile 1 for my mounts, but have also had luck with a bicycle grease that may have been Park Tool, but I don't remember.

 

I also agree with Uncle Rod: the mount does not require a lot of grease.  All you have to do is "pack" the roller bearings to make sure all surfaces are coated.  It's not necessary, or desirable, to fill the entire chamber that the bearings are in.  All that will happen is the grease will migrate where you don't want, like the clutches.  I think your EQ-5 will have nylon or PTFE spacers instead of thrust bearings; a thin film on these spacers is all that's required.  A thin film on the worm wheel is all that's required, too.  The worm will lubricate itself as it turns againt the worm wheel.  If you use a lot of grease on the worm, you'll end up with a big blob of grease at each end of the worm as the worm pushes the grease out of the way while it turns.

 

The loads on a telescope mount, by industrial standards, are very light, so you don't need a "super grease".  The advantage of a bicycle lubrication is that it will likely be hydrophobic (won't absorb water in dewy conditions) and will be formulated for the light loads that your mount will impose.

 

To answer your "how does it move" question:  the motor turns the worm, which is meshed to the worm wheel so the worm turns the worm wheel.  If the clutch is disengaged, then the worm wheel just turns.  If the clutch is engaged, then the worm wheel is locked to the shaft and when the worm wheel turns, the shaft turns with it.



#11 tazer

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Posted 24 February 2015 - 11:28 AM

I'm not a grease expert but Superlube is rated to -45F while Park Tool bicycle grease (Polylube 1000) is rated to only -10F. I'll probably never setup and image below -10F but it's something to take into consideration.

 

Mark



#12 EFT

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Posted 24 February 2015 - 03:39 PM

Definitely SuperLube, and as Rod says, very little of it.



#13 Eddgie

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Posted 24 February 2015 - 08:02 PM

Greetings,

 

Sometime before summer hits the Pacific Northwest (and thus clear skies), I'm planning on doing a teardown and rebuild of my EQ-5 mount.  After studying many guides and forum entries from lots of astronomy related sites, I'm scratching my head at what grease to use.  For the worm gears, I'm almost certainly using a white lithium grease, but I'm unsure about what to use for the actual bearing surfaces.  I've read that some people say use white lithium grease for all surfaces, but others say that is too thin and you need something thicker (but not as thick as the glue grease the manufacturers use).

 

Also, this may be a stupid question, but how does the worm gear turn each axis of a GEM?  I like to think that I'm at least competent at using these sorts of mounts, yet I've never really gotten how the rotation worm assembly affects the axis.  I get that a worm gear is an inherently one directional system and that the worm gear can never turn the worm, but is there just enough friction that the worm turns the axis, but the axis doesn't catch too much on the worm? 

 

Thanks!

 

 

The worm gear is the input gear and it turns the worm wheel.  As you have surmised, only the worm gear itself can drive.

 

I am not sure if I understand your question, but in your mount, there are two separate worm gears and worm wheels; one for each axis.  They are completely independent of one another.

 

In these mounts, only the RA gear is driven all the time.  The Dec gear only drives when slewing to a new target or when you manually move the scope in Dec.  Otherwise, it just sits there idle.   And of course if you are using a guider, that can also send signals to the Dec gear, but these mounts don't track in Dec.  If your polar alignment is off, the target will in time drift out of the field either north or south.

Again, I am not sure that I understand our question, but hopefully this helps.



#14 fetoma

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Posted 25 February 2015 - 08:38 AM

I'm getting ready to hypertune my CGEM-DX in which I will be using SuperLube, but this time (I've hypertuned many mounts) I'm going to mix in a little WS2 powder with the grease. I might even spray the internals with some WS2 dry film lube. Here are some links to this stuff.

 

http://www.microlubr...-1-2-3-1-3.aspx

 

http://www.archoilca...ection-4oz.aspx



#15 HBNorm

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Posted 25 February 2015 - 10:32 PM

I fifth, sixth, seventh, or eighth... Super Lube.  Used it on all of my mounts and focusers when rebuilding and it has performed flawlessly every time!



#16 russ_gibbons

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Posted 25 February 2015 - 11:10 PM

I've tried White Lithium Grease (OK if you plan to change it every year or two, but after 3-5 years the oil and thick white solid seperate, leaving a gummy solid, and oil dripping where you don't want it.

 

I've tried bicycle grease of various brands,  It is OK, but messy if you touch your cloths to it, (which often happens while feeling around in the dark).

 

I've done several mounts with Super Lube, and it is by far superior to the others.  Long lasting, not messy, great lubricant.  Unfortunately it also cost more than the others.

 

Unlike previous advice, I like to use a large quantity of grease in certain places.  Yes, you don't need much to lubricate the grinding surfaces, but the extra grease acts as a barrier to keep liquid and dust away from the grinding surfaces, such as the gear box.

 

Russ G.



#17 Startraffic

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Posted 26 February 2015 - 10:51 AM

Nashtok,

SUPERLUBE! Not a lot of it. One small tube will last you for YEARS! A can... forever.

 

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#18 nashtok

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Posted 26 February 2015 - 12:19 PM

Well superlube it is!  Thanks for all the responses.  Besides being conservative in the amount used, are there any particular ways to apply the lube such that it really gets in there where it needs to?

 

Fetoma, I and I'm sure others, would be interested to see how the WS2 dry film works on a mount.   I hadn't heard about it before, but reading about it, it sounds interesting.  I particularly am interested in the .03 dynamic and .07 static coefficient of friction claimed.  PTFE is .05-.1 depending on who you ask, so WS2 coated surfaces have less.

 

The question I had about the worm turning the axis may be related to the thick grease in my mount.  I don't have a motor drive (yet) so that isn't relevant.  Mostly, I was just curious how, even when I disengage the axis locks, I can turn the slow motion controls and rotate the axis.  Maybe the thick grease is giving just enough friction that when well balanced, the axis don't have to be locked.



#19 macdonjh

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Posted 26 February 2015 - 01:41 PM

The question I had about the worm turning the axis may be related to the thick grease in my mount.  I don't have a motor drive (yet) so that isn't relevant.  Mostly, I was just curious how, even when I disengage the axis locks, I can turn the slow motion controls and rotate the axis.  Maybe the thick grease is giving just enough friction that when well balanced, the axis don't have to be locked.

 

That's a reasonable theory, Nashtok.



#20 JMW

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Posted 26 February 2015 - 02:05 PM

Is this the right version of Superlube? This is the Amazon description:

 

Super Lube Synthetic Grease with Syncolon Multi Purpose Lubricant 3 oz

 

It costs $5.21 Prime. If I was going to replace the stock grease in a G11 RA and DEC worm gears would I need more than 3 oz?



#21 fetoma

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Posted 26 February 2015 - 02:16 PM

More than likely not.



#22 bobzeq25

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Posted 26 February 2015 - 02:23 PM

Well superlube it is!  Thanks for all the responses.  Besides being conservative in the amount used, are there any particular ways to apply the lube such that it really gets in there where it needs to?

The problem usually isn't applying the new lube so much as getting the old lube off completely, with getting solvent where it shouldn't go.  I don't know the answer for that except care, and possibly some disassembly.  Said disassembly would help with the new application, of course.

 

As far as how a worm gear works, it's basically a one way device.  The worm can turn the ring gear but, hopefully, the ring gear can't turn the worm.  No friction is required for that, and any friction between the gears is undesirable.  The friction should be applied only with clutches or other locking devices.


Edited by bobzeq25, 26 February 2015 - 02:28 PM.


#23 nashtok

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Posted 28 February 2015 - 05:01 PM

 

Well superlube it is!  Thanks for all the responses.  Besides being conservative in the amount used, are there any particular ways to apply the lube such that it really gets in there where it needs to?

The problem usually isn't applying the new lube so much as getting the old lube off completely, with getting solvent where it shouldn't go.  I don't know the answer for that except care, and possibly some disassembly.  Said disassembly would help with the new application, of course.

 

As far as how a worm gear works, it's basically a one way device.  The worm can turn the ring gear but, hopefully, the ring gear can't turn the worm.  No friction is required for that, and any friction between the gears is undesirable.  The friction should be applied only with clutches or other locking devices.

 

Yeah I'm definitely going to do a complete disassembly and grind off any burrs or inconsistencies in any washers, bearing surfaces, or whatever else I find.  I also have access to sheets of PTFE and a laser cutter so I can cut some new washers if needed  :grin:

 

The mount performs decent, especially considering the price, but I want to bring it up to as good as it can be!



#24 Bart

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Posted 28 February 2015 - 10:55 PM

Superlube. Hands down, the best.........



#25 Startraffic

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Posted 02 March 2015 - 07:22 PM

Jeff,

3oz will do a G11 4x-5x if you don't go nuts. 3x-4x if you do. I bought the 1# can 10yrs ago & still have more than 1/2 left after doing my GP, LXD-55, ETX, G11, & HGM a number of times.

 

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