NEQ6 Strip & Tune

[MG1]

Thought I should share some pics from my NEQ6 Strip and Tune...I've taken a few photos throughout the process that I need to sort out, and so far I've only stripped it, cleaned it and replaced the bearings....next weekend I have promised myself some time to tune it.

Many thanks must go to Mel (Astrobaby) and Dave Rankin for their websites and for reproducing the stoneyhill observatory tips.

EQ6 Strip Down Guide

EQ-6 EQ6 Atlas EQG Rebuild Hyper-tune Guide | Rankinstudio

I hope to get some proper notes up online at some point but couldn't have done anything without these two websites open on the lappy throughout the day.

Here's some starter pics for ten:

Hope to see some of you at Astrofest in a couple of weeks

CS

Michael

[themos]

Yowsa!

[MG1]

oh yes... the photo doesn't show it, but i've even removed the conical bearing races to allow them to be replaced with new SKF ones!

With it all stripped down I was very tempted to give it a custom paint job, but resisted!

The clock is ticking though...I need it all tuned and working before Kielder or there will be hell to pay!

[Astro_Baby]

I was thinking of giving the EQ6 I am working on a custom paint job as well but also resisted

I am curious - how did you get the measurements for the bearing face to upper face of the worm wheel ?

[MG1]

The other measurements were taken as in these pics:

[lukebl]

That looks terrifying, but impressive! I have an NEQ6, and I hope I never have to take it to bits.

I'm not known as 'Captain Cr*p at DIY' for nothing.

[Astro_Baby]

Is that a smurf taking your mount to bits ?

[Astro_Baby]

DOH ! Cant believe I didn't suss that measurement- course I havent started work yet but I was looking at the mount and thinking how will I do that measurement - DERRRRR ! I can only say its been a very, very long day at the day job And coming home and having a large brandy has fuddled me up a bit.

MG whats your view on the bearings ? I am aiming to replace the worm rollers end bearings as part of the rebuild but all of the mounts I have stripped so far have had pretty decent bearings in them. Given the fact that the mount is hardly ever moving very fast I really wonder about the value of changing the main axle bearings or the thrust bearings.

All the ones I have taken to bits so far have suffered various problems ranging from corrosion, poor lubrication and horrible mistreatment but the bearings have always been as good as anything apart from the worm roller end bearings which always seem to be ok but not great.

What do you think ?

[MG1]

Hi Mel, yeah Pappa smurf is quite a mechanically minded little guys....with big hands!

As for bearings....I agree, the main bearings were sound. Even the worm bearings were okay, but I figured that this was more of a convenience to replace all in one hit. Although I'm hoping that by doing so I don't introduce any new eccentricities.

I'm glad I did it though, as the spacings were quite a bit out (0.025") although so of that may be down to the lapping of the worm housing and removal of paint from the body face.

I plan to have a fiddle at the weekend....will update then.

Cheers

Michael

[Zakalwe]

Has anyone ever thought about using ceramic bearing in these? Some people use them in motorbike applications (for wheel bearings). The reduction in friction is astounding..... a heel with normal bearings will stop spinning after about 10 revolutions , if spun by hand. With ceramic bearings, the wheel will spin for about a minute.

Now I know that the application differs, as the bearing in a mount is moving at an altogether different rate, with very little load, however the ceramics are much better built, so "stiction" (initial resistance to movement) will be a lot less. I would also assume that due to the tighter tolerances within the bearings that Periodic Error may be reduced (I would guesstimate that some might come from the bearings as the rollers rotate?).

[MG1]

It is something I had considered, but in the end decided on going for a high quality (SKF) steel ones. I'm not sure if ceramic are necessarily 'better' build quality, but maybe someone who has done this could comment.

I believe that some of the hypertune 'kits' come with ceramic bearings. Maybe that accounts for their relatively high cost?

Good point though.

[Zakalwe]

Its a cracking thread BTW.

I think that there are also "pre-loaded" steel bearings available. These have much tighter tolerances than off the shelf ones, and are a lot smoother. Again, these are sometimes used by chassis tuners in the headstock of racing bikes. The finer, smoother movement makes a big difference to the handling.

I guess for a mount application, you are looking for low stiction, low periodic error caused by eccentricity and low rolling resistance. Self lubrication or Teflon rollers would also be nice!

[Astro_Baby]

Personal opinion having rebuilt a few of these mounts is that the basic mount engineering is not that great, the tolerances are quite sloppy compared with ( for example) a car engine.

Most of the mount casings are cast from a pretty average pot metal and machined off in places, paint application is weird with paint on mounting surfaces etc.

Ceramics and so forth might improve it a bit but I would doubt it would make a huge difference because the base engineering is only so so.

It woud be rathef like fitting a gas flowed head to a lawnmower, it would improve it but the change would be scarcely worth the effort.

I could see that an engineering shop could make far higher precision gear sets ( and someone used to do this ) but the cost was off the clock.

These comments should not be taken as having a downer on Synta mounts. For the cash they cant be faulted and with a little patience and tuning they can be very lovely mounts....my own HEQ5 is a wonderment after tuning and fettling. Quiet as a grave and vefy, very smooth.

Its just as I say I really wonder id ceramics and posh bearings really make a difference when the real culprit in the noise amd roughness stakes is the gear train.

I only do visual so lack the equipment to check out a PEC response, it would be very interesting to compare an ex factory model with a rebuilt and tuned model with factory bearings and a rebuilt and tuned model with one of the posh US Hypertine kits and see what happens. I'd happily supply my rebuilt EQ6 when its ready for testing as a comparison unit. Ex factory units are easy enough to source from anyone who has one. All we need is a test bed to assess it, would be a great test I think.

[MG1]

I only do visual so lack the equipment to check out a PEC response, it would be very interesting to compare an ex factory model with a rebuilt and tuned model with factory bearings and a rebuilt and tuned model with one of the posh US Hypertine kits and see what happens. I'd happily supply my rebuilt EQ6 when its ready for testing as a comparison unit. Ex factory units are easy enough to source from anyone who has one. All we need is a test bed to assess it, would be a great test I think.

I agree...would be interesting to compare. I sort of fell between the cracks...spending significantly less than the full on 'posh' US upgrade kits but probably more than what is considered necessary (Teflon spacers & worm gear bearings) although I'm not sure if all of the 'kits' even bother changing the thrust bearings, so there is probably a few quid to be saved there!

Btw, if anyone is interested I've some Teflon spacers spare as I ordered a few sets at the same time to cut down on delivery from the US and customs handling charges. PM if interested...I'll put something in buy when I get a moment.

[MG1]

I've not had much chance to fiddle this weekend so far, but did perform a little mod to the area that the alt adjustment bolts push against.

The first pic shows the damage caused by the original alt bolts. They have cut into the mount and (this may just be speculation ) form a recess that results in some adjustment difficulties.

In the second pic I have filed down the burr cut a small (20x30mm) section of 1.2mm stainless steel plate. I formed this to the curved shape required by clamping it in a vice and tapping with a hammer...few taps and then releasing a little more out of the vice.

The final pic shows it in place, fixed with two part epoxy, which I then removed from the surface with some wet and dry paper.

I'm not sure this will have much effect, but as the mount was apart it didn't take long to make this quick mod to both sides.

[Steve 1962]

Hi Michael

Great thread!

How easily did your mount come apart??

I'd like to do a tune-up on my mount but I'm a bit wary of using hammers etc to drive parts apart

Cheers

Steve

[Astro_Baby]

Sorry to jump in - I have done two EQ6s and both were complete bitches, one much worse than the others.

I have the feeling that No3 which I am planning to do next weekend will be easier though. Initial bits removed have come away easily whereas on the other two every nut and bolt had been done up by He Man or King Kong.

You do need a good selection of tools including a rubber or wooden mallet, hex keys, screwdrivers, and possible a flex wrench or oil filter wrench. YOu also need a fair amount of time and patience.

They arent rocket science but you do need a knack with mechanical stuff. I worte a complete step by step guide - its on my website in my sig with pics and step by step instructions.

[Steve 1962]

Thanks Mel

I did an HEQ5 using your guide - brilliant - many thanks. The results more than made up for the hassle.

I'm just sitting here looking at my shiny new NEQ6 with a bit of trepidation - several people have said they're swines to take apart and I don't want to break the thing.

Regards

Steve

[MG1]

HEHEHE....what can I add that the master hasn't already mentioned...

I was very fortunate in that it did come apart easily. Removing some of the bearings did require the gentle tap of a mallet, but be patient and work around the bearing gradually. My polar scope and locking nut were only 'tight hand-tight' and didn't require a great amount of leverage to undo.

One area I did struggle with was replacing the bearings into the RA main bearing housing. (this is the one Astro Baby shows being tapped in with the handle of a hammer) I struggle with this before deciding to try heating the housing with my hot air gun.

I was a little worried I may strip the paint, but kept the air focused on the bearing housing for a couple of minutes and it must have expanded just enough to allow the bearing to slip in comfortably.

Apart from that everything went well. Although I guess we should reserve judgement until i get the gear mesh sorted and loose the wobble that seems to have appeared on the DEC axis...

One final thing to mention is that on mine, I removed the covers with the logo and scale as I needed to tighten the grub screws that press on the ALT adjustment bearing plate. (there was wobble here too!) Mine did not come off easily and I am in the process of sourcing some replacements. Unless you need to tighten these screws and/or wish to add the steel plates as above, I would leave these in place so that you keep your mount looking its best!

HTH

Michael

[astroimpulse]

You're doing a grand job there! Properly thorough

You've also done a great job with the steel plate

RE: Bearings (for other's info): All the bearings are budget (international standard) in the EQ6. I figured the large ones could stay as the tolerances aren't noticeable in such large ones. But the worm bearings are poor. They feel ok but when felt next to a decent set (which are still cheap) the difference is so apparent. even the missus was shocked. A worthwhile change IMHO

[astroimpulse]

PS. Ceramic ones are only preferable in very fast moving devices. They stop the issue of steel bearings fusing together. Which they do (from my heli days).

But in this they would be adversely effected by cold...so steel is really the way to go. MG1...you've picked the rubber sealed ones which...IMHO...are the best for this

This thread coupled with AB's site should make most confident enough to have a go.

[Astro_Baby]

Thats reassuring Sy as I plan on doing the same with mine - in your estimation are the US posh hypertune kits worth the cash ?

I took the same view as you that the big bearinngs arent that bad for the job in hand and the overall tolerances of the main axles in the mount arent that fantasting anyway but as someone used to working on higher precision/more complex engineering I'd be interested in your views on that for sure.

Steve if your NEQ6 is brand new and works ok I;d always advise leave well alone. The EQ6 I acquired recently has a nasty 'stiff spot' in its RA axis and the DEC is very wobbly. I have meaning to write a hypertune guide for ages but never had an EQ6 handy. Oddly now I have my own I almost cant be bothered (cobblers sons being ill shod there I guess).

MG1 - did the main worm gear (the big round brass one) come off easy enough on your RA axis - on the HEQ5 they just slip down the axle/spindle but EQ6s seem to have a nasty habit of binding super baldy when you try and slip them down the axle/spindle. The one I used for my strip down guide showed hammer marks on its surface which the factory must have done to bang it into place. It was an early one and I suspect QC wasnt all it should have been.

[m.tweedy]

Hi Michael you KNOW there are always some bits left when you put something back together. WEEELLL if it just happens to be a tiny grub screw that would normally align a polar scope I know a good home it can go to

[astroimpulse]

Hi Mel, I've never heard of a kit to tune these to be honest

What does it comprise of?

If it's bearings...you can get them all from bearing King. I nearly changed the bigger ones...but purely because I could. I think I made the right decision by just cleaning up the current ones like you did.

Here's a link to the worm ones (but type in any code and you'll get the options). I forgot the codes for the bigger ones but you can see them as yours will be dismantled. I went with the 608-2RSH SKF if memory serves me well. Bearings

[astroimpulse]

Hi Michael you KNOW there are always some bits left when you put something back together. WEEELLL if it just happens to be a tiny grub screw that would normally align a polar scope I know a good home it can go to

Can you remember it's size? Or show me exactly which part of the polar scope. I have loads of black grubs at different lengths but they're all similar threads (M5 or something...I'd have to check). But if it fits...I'll pop some in the post.