Re-greasing NEQ6

[coenie777]

I do not seem to be able to find a post that answer my questions in full so please assist with the following:

I have stripped the DEC axis on my NEQ6 with the intention of just re-greasing it. I bought this mount second hand and was dreading what I would find.

I was quite surprised to find the insides in a very good condition in my view. I would appreciate some feedback on what you think of the condition of this mount from the photos attached.

I think the teflon washers are still in a very good condition and will not replace them now. I had to hammer the worm gear a bit to get it out and found that the sealed bearings on the main axis did not want to move by hand. Since I will not be replacing them, I will leave them as is for now.

I sanded down the over spray and hope that I did a decent job.

1) Please tell me if it would be a good idea to just wash the worm and the other exposed gears with dish washing liquid and a toothbrush or should I rather use a commercial degreaser?

2) Then the age old question around what grease to then put back on. Locally in my country I cannot for the life of me source any of the mentioned greases on any of the major forums. I will need to import some via Amazon and then even I am limited to Superlube. I have a pot of grease that says "Lithium grease, with added molybdenum". It is a dark brown color that becomes a bit more translucent when applied. Should I use this in the mean time or rather wait for my Superlube to arrive?

3) Lastly, I see that there is a very thin layer of grease on the inside of the setting circle, around the declination gear, the teflon washers etc. Should I apply a thin film around these again when I assemble?

4) Since I will not be removing the sealed main bearings or the worm shaft bearings, should I apply some grease there too or should they be fine? Any reference to a site where I can see exactly where I need to grease and where not?

The conical bearing housing:

The conical bearing itself and its grease:

Overspray on lower casing and some old grease smears:

Condition of Teflon washer as it sits:

Other Teflon washer before removing it:

Condition of the two washers:

DEC Gear with its grease as I got it:

Is this curvature normal on this gear (I guess I would not have been able to get 90" shots if it were not

Over spray and rough edges from a tool it would seem on the upper casing of the worm:

More machining and over spray issues:

Indentations on worm shaft from the screws attaching the gear to the worm shaft. Is this normal?:

The mount as it sits now:

[malc-c]

Lithium grease is the stuff to use.  Often sold in cycle (pushbike) shops.

Google came up with http://www.bruces.co.za/newfindus.html

Best to clean off all the existing gunk.  It looks like the previous owner has already serviced the mount as the black tar like stuff is the factory grease, and most of that seems to of been removed and replaced with the light brown / yellow stuff.

[JamesF]

And the worm wheel (DEC gear) is supposed to be that shape.  It's how they work.

James

[Steve Ward]

I am informed , by one who should know , that in truth the grease used at manufacture/assembly is a proper dampening grease selected correctly for the job .

The idea that there is a need to strip it all out and replace it with an 'expensive' lithium grease ... on a unit that operates , at sidereal rate , for a couple of hours , once in a while , is little more than mythical.

I think that the "let's strip this thing down and see if I can tweak it" thing has probably developed more from cloudy evenings , wet weather boredom coupled with some folks 'need' to tinker away in the shed than any real "problem that needs fixing" scenario.

Regarding the 'overspray' and 'machining' , these mounts are made very well in general . but to a price that brings them within reach to most ... if you want much better machining , finishing and performance then you need to have deeper pockets and look somewhere other than Synta.

[perfrej]

I replaced all bearings on my NEQ6 and it makes a huge difference. The bearings that were there from the factory were consumed after a little over a year of use. Being Swedish, SKF came to my mind and I found exact replacement bearings from their catalog. The difference in quality is enormous... SKF bearings do not corrode in a year as the originals had.

As for re-greasing, the quality of the grease the factory puts in there is definitely questionable. There is grease and then there is grease, the latter preferred. I asked the guys who sold me the bearings what I should use. One interesting property is how the grease behaves over changes in temperature, and I ended up getting a small tube of Barium grease - at £35! The grease the factory had used was well distributed, yet the bearings corroded. That says a bit about the grease.

The NEQ6 is a low cost mount, and as such it is subject to imperfections and lack of quality control. Among the six or seven ones I have seen, the differences in feel and performance have been signifficant. The basic design - copied from Takahashi and Vixen - is good, and there is no reason why a simple tweak session should not make the mount excellent and on par with many almost premium mounts. But in original configuration it is what it is; a product spaced out randomly over the quality spectrum...

So, my advice is to give it a going over. If you search the forum you will find my post with the bearing part numbers from SKF. Any high quality (and expensive - these things are no free lunches) grease will do, be it Lithium, Barium or straight marine application.

My national pride invites you to read about SKF on Wikipedia: https://en.wikipedia.org/wiki/SKF

All the best,

Per

[malc-c]

I am informed , by one who should know , that in truth the grease used at manufacture/assembly is a proper dampening grease selected correctly for the job .

More along the lines of "lets put some thick gunk in there to fix the amount of backlash and float we have in the gears"

If you class £2 for a tube of Lithium grease as "expensive" then you must be tight

To be honest, there is an advantage to a strip down and re-grease of the mount.  Since I did my HEQ6 the motors now draw just 1100mA in total with both motors slewing a 200P explorer with ST80 piggybacked on top.  Before it was more like 1800mA, so there is less drag through the gearing.  It does take some higher degree of tuning the mount as the low tolorances the mount is produced to become more evident due to the lack of  "cusioning" effect of the gunk Synta use, but there are benefits to be had IMO.

I agree these mounts are good for what they are.  £750 ish for an HEQ5, £900 or there abouts for the EQ6 both mass produced, you would expect things like overspray or areas where castings could of been finished off better.  But these mounts can be improved with the use of better bearings, better lubrication, conversion to belt drive, and tidying up area's where parts meet to give a better interface... without he need to dig too deep into the pocket and well within the amount the next step up would cost for something such as an EQ8 / Avalon mount.

[goose35]

I think its 1000 year old whale blubber to grease them at the factory

[goose35]

I did my cg-3 in feb before i upgraded and used teflon grease also for bikes.

The improvement was id say 150% even on the cg-3

[coenie777]

Thanks for all the replies.

Per, SKF bearings is already on my wish list with your generously provided part numbers saved on my phone just in case I walk past an SKF supplier.

I managed to find a tube of Loctite white lithium grease. The supplied told me they only got six tubes in and I took the last one. But at least now I have it. I actually visited five bicycle shops in my home town of Pretoria (close to Johannesburg) and no one had white lithium grease. So it looks like this may not be that big on the SA bike scene as overseas. I did see some Teflon grease there now that you mention it.

I now dismantled the RA axis as well and there is plenty of the yellow grease all over there as well.

I will now proceed to clean the parts so I can re-grease tomorrow and start the seemingly agonising task of getting the lot aligned again.

Appreciate the advice so far.

Any views from existing NEQ6 owners around the general condition of the mount's insides? To my eye it looks very good with minimal wear. I did not find one bearing so far that feel or look like it is end of life.

[Alien 13]

I am another big fan of the skywatcher grease its composition and stickness is there for a reason, looking at some of the images it seems that the replacement type runs away leaving metal to metal contact.

I had better run now I can hear the linch mob approaching.....................

Alan

[Dave grim]

As Per says I would get a good quality grease and clean all the old grease off and reapply with the good quality stuff , I know it's not the same but I have done this a couple of push bikes and motorcycles where needed and the parts move so much better , if you ask any mechanic that is good at his job they will swear by a good quality grease on moving parts that need it .

Dave

[perfrej]

Yes, again, it doesn't have to be the most exotic grease - just make sure it is of high quality. I would imagine standard marine lube grease is good, for instance.

The grease in my NEQ6 smelled of old fish (for lack of a proper term) and didn't stick very well to the metal. The mount was just over a year old, so I don't buy the "good grease from the factory" scenario. Besides, if the axis corrodes even with grease on it, something is not right.

/per

[coenie777]

Thanks, just another quick question on a related matter:

The roller bearings on each side of the worm gear, should they be greased as they seem to be a closed unit to my eye. I would take it that you do not grease the outer side of it or the area where the shaft goes in?

[coenie777]

Another question: what do the teflon spacers do? Are they static or do they rotate when assembled?

[Alien 13]

Yes, again, it doesn't have to be the most exotic grease - just make sure it is of high quality. I would imagine standard marine lube grease is good, for instance.

The grease in my NEQ6 smelled of old fish (for lack of a proper term) and didn't stick very well to the metal. The mount was just over a year old, so I don't buy the "good grease from the factory" scenario. Besides, if the axis corrodes even with grease on it, something is not right.

/per

I agree that doesn`t sound good I suspect bacteria have attacked the grease, my point was that SW do things for a reason and it hard if not impossible to upgrade any part in isolation take the bendy bolts as an example changing them for a stronger item results in other problems related to poor material elsewhere.

The solution you came up with is however sound, change the bearings (the real issue) and then apply a better lubricant.

Alan

[Stub Mandrel]

The small closed unit sealed bearings should not be greased. They should be good for several hours a day at a few thousand rpm for years...

Note on the big roller bearings - the proper amount of grease to use is 25-30% of the space in the bearing, although a mount won't move fast enough to cause damage.

The ideal way to set roller bearings is to tighten them, up until they run hand-hot, but again mounts don't go that fast. Just remove all play and add a tiny tweak.

+1 for teflon grease - it leaves a protective layer even if pushed out of the bearing under long time static loads (as when the mount is left set up). Moly and Lithium greases are good for this as well but teflon grease is so much more pleasant to use... Moly is for very high loadings and is probably OTT for a mount.

Now I ask a sneaky question - is there an exploded diagram of an EQ3/NEQ3 mount anywhere?

[malc-c]

 Moly and Lithium greases are good for this as well but teflon grease is so much more pleasant to use... Moly is for very high loadings and is probably OTT for a mount.

I would not recommend Molly grease - It's far too abrasive for this IMO

[coenie777]

Alan, I have to agree with what you say as it seems a lot of people previously mentioned that the black grease SW used worked great at picking up backlash/slack in the assembly.

But that slack might have been there as it did not make economic sense for them to spend tens of minutes or hours tuning it to perfections. So lap some tar on it after a 10 min tune and off you go. I do believe that if you have the time to now reduce tolerances you will no longer need the black stuff and will benefit from better grease. But that is coming from someone who could not get the mount back together today on first try. So use it, don't use it

Glad to hear that I do not have to grease the sealed bearings. I will try that 25% of space rule tomorrow when I hopefully re-assemble. Sorry, I could also not trace any exploded view/schematic of the NEQ3. Maybe try SW site.

Last questions I would appreciate an answer is the teflon washer, should it go completely dry into the shaft or should it be lubricated? Same for the large and small sealed bearings. They need to go bone dry into their slots which also should be dry? Or should they get a smear of something?

[kalasinman]

I would not recommend Molly grease - It's far too abrasive for this IMO

I'd love to see some data that Moly is abrasive. Really?

[perfrej]

Sealed bearings are "filled for life", where "life" usually means high RPM and 24/7 use, which is not the case here.

The teflon spacers are shims and I think they should be lubricated by applying a very thin coat of grease or oil.

Bearing "tightness". As stated above, hand warm is a measure for rotating assemblies. For your NEQ6, you tighten the axis until you a slight resistance when hand turning it, then back off just a tad. The worm bearings are tightened by going for minimum slack, the slack you can feel on the main axis itself and on the worm axis ends with your finger.

/per

[Stub Mandrel]

I would not recommend Molly grease - It's far too abrasive for this IMO

As far as I can see from the net this is only an issue if the grease has much too big moly particles in it... easily avoided by using a decent quality grease.

[1parsec]

My NEQ6 mount was bought new 2 years ago.  

I stripped the mount shortly after purchase to fit a belt kit and the internals weren't covered in the heavy black grease but instead lightly coated with a much lighter lithium grease ( light brown / yellow colour)

It would be interesting to know when Skywatcher stopped using the black gunk.

I regreased it with Aeroshell Grease 33MS  - MIL-G-21164 which is the grease now recommended by Astro-Physics to use on their mounts.  A 400 gram cartridge cost about £16 and is a lithium base with + 5%molly.  

I got the grease from http://www.transair.co.uk/sp+AeroShell-Grease-Aeroshell-Grease-33MS-400gm-Cartridge-MIL-G-21164D-DEF-STAN-91-57+2933C

[Steve Ward]

An EP grease would still seem to be the best bet going by this from the SKF Selecting a grease page ... 

[coenie777]

Well I got the mount back together, think I have the worm aligned but still heard a funny noise. Ends up being one stepper motor's spur gear that I did not tighten. I then also saw that the grease I applied did two things which I would appreciate some views on:

- It separated from the gears and formed blobs on the edges of the gear. Was this too much grease or just low quality grease?

- The white grease turned a slight grey color in places. Could this be normal reaction or something else? (my Lithium grease came out a non translucent white paste)

I see some awesome grease referrals liking the fact that some are suggested by the premier mount manufacturers and bearing makers. I will see if I can source some but unfortunately wide of using Amazon this is just too expensive. If Amazon cannot ship it (and there are more items they cannot ship than the other way around), I will have to go with what they can ship. This looks like it might leave me with Superlube after all.

[kalasinman]

So what's the problem with Superlube?