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Mount grease

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Hi

I have just stripped down, cleaned the gears and eliminated the RA and Dec backlash in my AVX. I've also fine-tuned the anti-backlash values in the hand controller.

As a temporary measure, I've sparingly applied some general use lithium grease I found in my garage to the gears, but I'm now looking for a more permanent solution.

I've read everything from lithium, PTFE, silicon, Teflon and who knows what else all being the right choice, but can anyone definitively point me in the right direction (preferably with a link where I can purchase at a reasonable price in the UK) as to what I really should be using?

Cheers,

Kev

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Nice one.

Never thought about using push bike lube.

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When I motorised my 20 year old EQ3-2 the motors were stalling so I stripped it down an removed the Synta gunk which had congealed to solid in places.

After much research I got a spray tube of "WD40 Specialist High Performance White Lithium Grease" of the sort which is much recommended.

In my judgement this is much to thin for the tiny contact surfaces in worm drives.

So instead I used some general purpose lithium grease that has been in my garage for about 20 years. Probably the same stuff you have used.

This is much thicker than the spray stuff but does not have the grab or the stiction of the Synta grease. It works great, no stalling and I'm sure it will protect the worm drives.

Personally I don't believe that only the most exotic & expensive grease will do the job. A mount is not an onerous application  compared the the very high loads in automotive applications etc. Just my opinion.

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To my mind it needs to be a grease that's not too sticky in the winter and not run like a river in the summer, or in doors..think geoptik do 2 types for different applications..on a side note how difficult was it to disassemble..did you make a Teflon washer for the DEC gear..I've heard it don't have a bearing..is this true?

Edited by newbie alert
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11 hours ago, newbie alert said:

To my mind it needs to be a grease that's not too sticky in the winter and not run like a river in the summer, or in doors..think geoptik do 2 types for different applications..on a side note how difficult was it to disassemble..did you make a Teflon washer for the DEC gear..I've heard it don't have a bearing..is this true?

Pretty much sums up what I've been led to believe.

I went to my local motor factors yesterday and looked at some silicon grease. Ruled that out, as it appeared to separate at room temperature. I'll consider all the above suggestions.

As regards disassembly, I only removed the RA and Dec gearing, not the entire mount. I'm a tinkerer, so only a matter of time before I do - if I find guiding not as good as I'd like it to be.

To be honest, it's good enough now for my current setup.

Kev

 

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Well today i had a bit of free time, so I only went ahead and stripped down the Dec assembly, as outlined in several readily available online guides.

Cut a long story short, the entire internals were smothered all over in grease - no wonder the Dec was so stiff. Bear in mind I removed most of it before I took these photos.

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Plenty of fine metal particles between the gears too, so a good soak and clean in solvent got everything sparking again.

There were three alarming fragments of swarf sandwiched between a pair of mating UHMW "bearings". Left undiscovered, I've no doubt they would eventually cause serious damage to the washers, possibly shredding them to bits, seeing as they are only plastic. Obviously, not great quality control at initial assembly then. Also probably explains why i felt the Dec felt graunchy, in certain positions.

I also fine grit wet-and-dried a conspicuous rough spot on the worm-wheel body (not on the actual teeth). I don't think it has any affect on performance, but i did it anyway.

Dried off then sparingly re-greased all the mating surfaces with the ever popular Loctite Super Lube.

Re-assembled everything, adjusting worm and spur gears. Powered up, and re-adjusted the anti-backlash settings in the handset. Job done.

Dec axis is still stiffer than RA (it always will be, as there's no proper bearing), but to my eyes it is an improvement on before, and no more "graunching".

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Got an impressive total RMS of 0.48" before the Dec stripdown (over a 2h+ run) a few days prior just by cleaning, re-greasing and adjusting out the backlash on the RA and Dec spur gears.

Hopefully guiding will be at least as good again with this full Dec axis service.

Kev

 

 

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I use Super Lube for all of my astronomical equipment...

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It's a PTFE(Teflon)- based grease, and quite adequate for up to an EQ-5 at least.  It's also food-safe, in case one wants to take their mount out for dinner.  It's neither thick nor thin; just right rather, and the perfect thing for replacing factory glue-grease...

36559999_factorygrease.jpg.90d13e2694d976b0994d21e7e091598a.jpg

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I re-greased my AVX with Lubriplate 130-A. It isn't temperature sensitive (at least not within the bounds a human can survive or is willing to endure). It clings well to gears without being "sticky". I use it on the trigger assemblies and bolts of my semiauto rifles. 

https://www.lubriplate.com/PDFs/PDS/3_14-130-Series.aspx

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I also used SuperLube - for my HEQ5 and EQ6 - worked perfectly - I also use it for rebuilding windlass gearboxes on boats - they do a similar job - slow moving parts under high load in extreme conditions.

I am not advertising but we sell it in our Chandlery if you want a tube - £12.50 posted.

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Yes thanks for that, but I already have a full tube for which I used earlier in the thread.

Barely used any, so plenty left for further work. I'll see how it performs when opportunity arises.

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