22 replies to this topic

[KurtV]

Hey all.

Like probably most HEQ5 owners, I thought my mount was a little stiff (although smooth) in dec and in RA.   And like probably most HEQ5 owners, I went to YouTube to become an instant pro on ripping stuff open.

So, this led me through a number of videos some good, some less so, but probably the most useful is the one by Astrobloke that I know most of us have seen.   But he's clearly starting with a used mount of unknown past.   So he starts with the rather aggressive approach of replacing all the bearings. with new, and comments along the way that at least a few of the bearings in his unit are a little notchy and probably were never very good.

At the end of his video (and other videos from other people do the same) he gives the RA a spin and it goes like a top, obviously moving a lot better.

But what I had some difficulty believing was that the bearings were the cause of all that original stiffness.   And since he's recommending buying about $200usd worth of bearings I thought I might take a more pragmatic approach.

My mount is pretty new, and I am its original owner.  So I have no reason to believe the bearings are all chowdered up.

So I dug in without ordering parts just to do a little exploratory surgery following Astrobloke's instructions.   Here is what I discovered..

1)  The bearings are  name brand JESA (a Swiss brand of reasonable pedigree, not some cheapo junk).
2)  The bearings were all free and smooth.
3)  There was some excess grease here and there, but not too bad.  I did clean it up a bit.

So what keeps your RA from spinning like a top on your HEQ5?   Its all over tightened.  Notice that when youtubers disassemble their mounts, they need the occasional tool to get the stays to break loose, but when they reassemble they go hand tight no tools.   Why don't any of them bother to point out that this is 90% of the problem?  Its not like they have affiliate links to bearing shops, so seriously it seems like a weird omission. New bearings are not necessarily the magic bullet.

Another hang-up on the RA could be the green RA marking ring.  If you have that fastened in place, it has quite a lot of friction with the other moving parts (which in proper use allows it stay oriented, so even if you're not using that ring, don't clamp it down with its little set screw, its not hurting anything if allowed to turn, and in fact allows everything to move freely).

To be 100% clear here, the main stay that is holding the bearings too tight is the one the green ring is surrounding, it has the three grub screws around the perimeter.  That guy can be simply loosened, then hand snugged and then reset the grubs to hold it in place.

Digging into the dec, I found the exact same problem.  In this case the one holding everything together is the assembly with the green dec ring and the counterweight extension clutch on it, this requires a fair bit of effort to undo, just undo that, and retighten to firm hand tight.  All bearings are were again JESA and were exceptionally smooth and free.

That's it.  If you have a reasonably new and well maintained HEQ5 there is NO reason to assume its full of bad bearings, it isn't.  Its just a little over snugged.

So there you go, and of course your mileage may vary.  I have no doubt that the people who tore theirs apart on youtube and installed new stuff did it because they needed new stuff.  But what they didn't explain is that you probably don't need to spend that money, and you could just adjust a few things and be on your way.  

I hope I saved you a couple hundred <insert your local currency here>.   Also, if you haven't already -- Astrobloke's video is an excellent discussion on how to do any thing you need to do.  You just might not need to do all of that.

Take care.

 

Edited by KurtV, 02 August 2022 - 05:04 PM.

[macdonjh]

Hey all.

Like probably most HEQ5 owners, I thought my mount was a little stiff (although smooth) in dec and in RA.   And like probably most HEQ5 owners, I went to YouTube to become an instant pro on ripping stuff open.

So, this led me through a number of videos some good, some less so, but probably the most useful is the one by Astrobloke that I know most of us have seen.   But he's clearly starting with a used mount of unknown past.   So he starts with the rather aggressive approach of replacing all the bearings. with new, and comments along the way that at least a few of the bearings in his unit are a little notchy and probably were never very good.

At the end of his video (and other videos from other people do the same) he gives the RA a spin and it goes like a top, obviously moving a lot better.

But what I had some difficulty believing was that the bearings were the cause of all that original stiffness.   And since he's recommending buying about $200usd worth of bearings I thought I might take a more pragmatic approach.

My mount is pretty new, and I am its original owner.  So I have no reason to believe the bearings are all chowdered up.

So I dug in without ordering parts just to do a little exploratory surgery following Astrobloke's instructions.   Here is what I discovered..

1)  The bearings are  name brand JESA (a Swiss brand of reasonable pedigree, not some cheapo junk).
2)  The bearings were all free and smooth.
3)  There was some excess grease here and there, but not too bad.  I did clean it up a bit.

So what keeps your RA from spinning like a top on your HEQ5?   Its all over tightened.  Notice that when youtubers disassemble their mounts, they need the occasional tool to get the stays to break loose, but when they reassemble they go hand tight no tools.   Why don't any of them bother to point out that this is 90% of the problem?  Its not like they have affiliate links to bearing shops, so seriously it seems like a weird omission. New bearings are not necessarily the magic bullet.

Another hang-up on the RA could be the green RA marking ring.  If you have that fastened in place, it has quite a lot of friction with the other moving parts (which in proper use allows it stay oriented, so even if you're not using that ring, don't clamp it down with its little set screw, its not hurting anything if allowed to turn, and in fact allows everything to move freely).

To be 100% clear here, the main stay that is holding the bearings too tight is the one the green ring is surrounding, it has the three grub screws around the perimeter.  That guy can be simply loosened, then hand snugged and then reset the grubs to hold it in place.

Digging into the dec, I found the exact same problem.  In this case the one holding everything together is the assembly with the green dec ring and the counterweight extension clutch on it, this requires a fair bit of effort to undo, just undo that, and retighten to firm hand tight.  All bearings are were again JESA and were exceptionally smooth and free.

That's it.  If you have a reasonably new and well maintained HEQ5 there is NO reason to assume its full of bad bearings, it isn't.  Its just a little over snugged.

So there you go, and of course your mileage may vary.  I have no doubt that the people who tore theirs apart on youtube and installed new stuff did it because they needed new stuff.  But what they didn't explain is that you probably don't need to spend that money, and you could just adjust a few things and be on your way.  

I hope I saved you a couple hundred <insert your local currency here>.   Also, if you haven't already -- Astrobloke's video is an excellent discussion on how to do any thing you need to do.  You just might not need to do all of that.

Take care.

 

+1

[El Mitch]

Hypertune came about with the first generations of these mounts and the dreaded black tar. I did multiple tune-ups on mine but then again it's a 2006 vintage. I agree it does not look useful in newer models.
One thing though that I found helped a lot: re-boring the inside of the mount as there is some friction with the brass gear (though only helps with balancing when the clutch is loose) but then again newer models are most likely better machined

[MJB87]

Moving to the Mounts forum.

[klaussius]

So what keeps your RA from spinning like a top on your HEQ5?   Its all over tightened.

You know, most (all?) of the SkyWatcher things I own had that problem. It seems to be a fetish of theirs to overtighten things.

[OzViking]

FWIW, I have a 3-month old HEW5-Pro.

 

When I was installing the Rowan belt kit I checked the bearings for smoothness of rotation. They all sucked - it was like the factory bearings had sand inside them, or non-round bearings.

 

When I replaced them, they all felt rough and did not want to rotate smoothly. The same goes for the factory grease - it was more like glue. 

 

KurtV has a point - things were done up far too tightly and loosening everything off a bit will help, but the factory bearings are still rubbish.

[Papagene]

Mine is arriving next week, brand new. I'll check it and report. In any case, top tier bearings are $100 (I had them in stock)

[KC_Astro_Mutt]

Best "tuning" video I've found on the interwebs, right here:

https://www.youtube....h?v=0yzFTjlpZaI

[Papagene]

Reporting back after some hours in the OR. 

 

As I mentioned, HEQ5 arrived yesterday, and since I've been having cloudy nights for the last month or so, I decided to go to town. The whole process took me about 3 hours with several hitches, that should be considered when doing this kind of mod and should be taken into account as part of whether it's worth doing it:

 

(1) the quality of some elements is definitely on the "budget" side. The grub screws were particularly low quality, and most of them overtightened (like the whole mount, actually). So much so, that I had to use a 7/64" (2.77mm) instead of the normal 2.5mm. This, after getting very sweaty palms after the screws started stripping.

 

(2) The quality of the larger roller bearings was good. They were smooth and without play. Both brass worm gears were well machined and changing the bearings went very smoothly, on the other hand, the steel pieces had very tight tolerances (emphasis on tight), so much so that, with the benefit of hindsight, I shouldn't have removed them in the first place. 

 

(3) The smaller bearings on the worm screws were the worst of the bunch, and I would definitely suggest replacing them if you are having tracking issues. They are easy to remove with minimal disassembly and you can actually feel the improvement. Also, I think these are the most relevant to tracking accuracy.  

 

(4) Special mention to the flimsy 12V plug. 

 

In conclusion, there are improvements to be made, but the gains on a new unit were marginal. And the risks of making it worse are very real for YouTube experts. I agree with Kurt.

[dcweaver]

Great observation about being overtightened.

 

I am always surprised when someone shows a "spin test" as evidence of a successful tune-up. It doesn't show much, if anything, about how smooth the mount will track. It only shows the mount will be easier to balance because the clutches don't bind. When the clutches are tightened, everything else in the drivetrain dominates and sets up a legitimate trade between ball bearings or bushings (at least for the DEC axis) depending on intended use and where a mount wants to be on the cost/performance curve.

[900SL]

I can't speak for the HEQ5 (my only SW experience has been the Star Adventurer, which was pot metal junk), but my Vixen mount is assembled using various grades and viscosities of lubricant, including sticky viscous grease. I think the purpose of this is to damp certain interfaces and reduce tracking harmonics. My Dec and RA axis do not spin, there's some resistance about both axes and this is intentional.

[AbsolutelyNot]

(2) The quality of the larger roller bearings was good. They were smooth and without play. Both brass worm gears were well machined and changing the bearings went very smoothly, on the other hand, the steel pieces had very tight tolerances (emphasis on tight), so much so that, with the benefit of hindsight, I shouldn't have removed them in the first place. 

 

(3) The smaller bearings on the worm screws were the worst of the bunch, and I would definitely suggest replacing them if you are having tracking issues. They are easy to remove with minimal disassembly and you can actually feel the improvement. Also, I think these are the most relevant to tracking accuracy.  

 

(4) Special mention to the flimsy 12V plug. 

I agree completely.  I followed Astrobloke's video and replaced all of the bearings as per his video.  As Papagene says, quoted above, the larger bearings were fine but the smaller bearings were junk.  They felt notchy and gritty even after cleaning and re-greasing.  The new bearings were reasonably priced and easy to replace as they didn't require a total tear-down.  However, even if you're not replacing the large bearings they still would benefit from cleaning and re-greasing with a quality grease.

 

Regarding the 12V plug:  mine failed intermittently so I replaced it with a locking style plug as per a tutorial out on the web.  I made a bit of a hash of it but it works perfectly so I'm happy.

 

After doing the Rowan belt mod and Astroblokes' hypertuning I can get guiding in the 0.4 ~ 0.5 rms range routinely with good skies.  I rarely reject subs because of bad guiding and that's all I can ask of a modest mount.

[Papagene]

... so I replaced it with a locking style plug as per a tutorial out on the web.  I made a bit of a hash of it but it works perfectly so I'm happy.

Here we go down the rabbit hole again, let's get welding this time

[AbsolutelyNot]

 welding

soldering

[Sparkie259]

Interesting read. I'm still trying to figure mine out. It is a brand new mount and very stiff. So stiff, it's hard to tell if it's actually balanced. I took it apart (following AstroBlokes video) and cleaned everything up. I used the original bearings but cleaned them up and re-lubed them with Super Lube.  The nuts on the ends are barely tightened at all and I had even left the screw out of the green ring of the RA. It is still stiff as hell. It's very smooth but what good does that do when you can move the counterweight a couple inches up or down and the mount doesn't move? Guess I'll be tearing into it again. I guess.

[Yerman]

Many people seem to get caught up in this issue that for a mount to work properly that it must float frictionless when the clutches are disengaged. This can never happen and if your does then there is something wrong with your bearing seals. The bearings in our mounts are sealed against dirt dust or any other foreign contamination. Take a brand new bearing straight out of the package and try to spin it. It will not spin does that mean it’s defective obviously not. The only way to get it to spin freely is to remove the seals and wash out all of the grease. Even then it will only freely spin before you oil or grease it. Our mounts typically have 3-4 bearings on each axis with 2 seals per bearing. So that’s 6-8 seals plus the grease that is expected to spin freely as in balancing. If you move an axis by hand it should feel smooth but as soon as you stop moving it it will stop immediately. Most of this is caused by static friction. As it’s name implies if it’s moving residual friction is low but when it’s at rest you have to over come static friction and inertia. To balance a mount you set the axis horizontal and gently push it off balance. Note if it wants to keep moving a little or does it stop instantly. Try that in both directions adjust and try again until there is no detectable difference. That’s it so stop replacing perfectly good bearings unless they are notch’s or gritty even then you can pry off the seals wash them out regrease lightly and replace the seals. The bearings in your mount are probably bigger than the bearings in your car wheels. They will never wear out.

[oatmeal]

I've done a full teardown, cleaning, and reassembly of both an HEQ5 and EQ6-R. I have never replaced bearings, but I have popped the seals on the larger RA/Dec shaft bearings, scrubbed them, and regreased with SuperLube. Most of them actually looked ok inside, but in a few I found yellowed, congealed grease that had begun to clump.

 

On my EQ6-R, I haven't noticed a significant improvement in tracking since I serviced it, though it's been mostly a problem-free champ since I bought it, reliably tracking from 0.6-0.8" with loads up to 30lbs, with occasional dips into the 0.4"s if conditions are particularly good. It still tracks that well after my reassembly (got a nice stretch of 0.4-0.5" the next night), so I'm relieved that I at least didn't create a problem that wasn't there.

 

With the HEQ-5, I did a Rowan belt mod at the same time, which was the mostly likely source of the improvements in tracking I saw: going from an average of 1.0-1.2" down to 0.6-0.8".

 

I agree, though, that the ease of spinning your clutch-released axes really is down to the tightness of your RA and Dec nuts, and there's little evidence that loosening it does anything to improve tracking. If you have a lighter setup, having it slightly looser than factory (while ensuring it's not too loose) may help with balancing. My EQ6 was starting to get a little tight before I serviced it and with my widefield setup it was difficult to tell if it was well balanced.

 

If your mount isn't misbehaving, there may be no reason to disassemble and attempt to "tune" it, especially if you aren't comfortable doing so. There are plenty of opportunities to inadvertently strip a screw or tear a wire off of a mainboard that'll really leave you up a creek for a while. For myself however, I'm glad I did, as it's given me a better insight into the internal workings of the mount, and I now feel reasonably assured that I can self-service my EQ6-R, should a problem arise.

 

 

Now my CEM70EC... that I'm not gonna fuss with 

[houndsbourgh]

I always thought the Hyper in the Hyper Tune was just all hype anyway. Being a mechanic for 35+ years I just do the tune up thing. I really like my HEQ5. But right out of the box I did the entire tear down and tune. Couple things I did fined not mentioned already were the worm drive bearing seats and drive deflection. The supporting bearings for the worms are a sloppy drop in fit. They can deflect with correction impulses from the motors. Preload lock rings suffer from this as well. During my rebuild I replaced the bearings and set them with a sleeve retainer. Low strength thread locker on the rings as well. Worms and drive rings were polished. The clutches will deflect the worm and drive ring when engaged creating tight and loose zones in rotation. I spent a lot of time running through complete shaft rotations turning the pulleys by hand. This helped me with the final adjustment and place the tight spots in unusable parts of the rotation. Bearings, belts, rail kit and a bunch of time could of easily justified another mount. At least what I have is a known quantity. Under clear sky with PHD2 running predictive PEC I have managed subs as low as .28-.40. Rock solid performer in the .40-.70 range.

Edited by houndsbourgh, 17 February 2023 - 01:16 PM.

[Kevin Ross]

The clutches will deflect the worm and drive ring when engaged creating tight and loose zones in rotation.

You know, that's the first time I've ever heard of this, but it does make sense. Very interesting....

[houndsbourgh]

Big trick is to prepare the clutch engagement surfaces so you don't need to over tighten the lever. Which I think is the best reason to clean out all the factory lube. Reassemble using grease sparingly and just where it is needed.

[900SL]

...... Bearings, belts, rail kit and a bunch of time could of easily justified another mount. At least what I have is a known quantity. Under clear sky with PHD2 running predictive PEC I have managed subs as low as .28-.40. Rock solid performer in the .40-.70 range.

Vixen SXD2 out of the box with 180mm guidescope and 178MM guide camera. Never touched anything on the mount

 

 

 

[KLWalsh]

When I hypertuned my CGEM I was careful to sand and polish the ring gears for the RA and Dec axes. The original surfaces were rough, pitted, and looked very corroded/oxidized. When I was done they were mirror-like smooth and spun quite easily with just a drop of Superlube. When I reassembled the mount, I tightened the axes per the video, and it which was pretty darn close to how it was when I disassembled it.

So, no. Done properly, hypertuning is not just hype. The mount was dramatically better after hypertuning.

[Shed9]

I can't help feel that there is some element of conflating a faster spinning mount with it subsequently being a better mount.

 

The priority for mount bearing lubricant is temperature operating range, adhesion, keeping it free of contaminants and application of proper bearing grease in the appropriate volume. As long as the bearing itself is not damaged or of poor quality then all is good. It doesn't need to spin like a flywheel or spin longer than the next mount. I've seen people take delivery of brand new mounts to automatically replace the bearings with no brand bearings with an alleged ABEC rating, Super Lube it within an inch of it's life, spin it and then feel a job well done has been accomplished. I particularly despair when people claim victory in removing 'that sticky' substance from worm drive assemblies. Worm drives in mounts are always going to be a compromise, by sheer design it wants to slide that lubricant off at every chance it gets. Short of fitting an oil bath, stick to the sticky stuff. 

 

I do see however where some will want to replace bearings with high grade units (SKF, FAG, Nachi, etc) prior to permanent installation in an obsy and I also appreciate sometimes people just want to tinker with their kit but I suspect with the glut of YouTube Hyper-Tune How-To's that more mounts are going through more drastic surgery than necessary.