HEQ5 Mount Technical Comments

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Kevin Cummins avatar
I recently obtained a new HEQ5 mount. 

One thing to be wary of is the quality of the fittings.  The clutch locks can be easily broken (mine arrived from the factory broken).

The bearings and worms were rough, and required polishing of the worm gear and complete bearing replacement to obtain smooth operation.  I used hybrid ceramic-ball bearings to replace the original units, which eliminated all notching in the axes.

The old way to set up proper gear lash (each worm has a drive pinion, a counter gear, and the worm drive gear) would be to place a piece of notebook paper (not printer paper) in the gear mesh and crush the paper, giving a consistent lash of about 0.0010".  However, the gears are not as precisely cut as I expected, and as a result the mesh is too open for good running characteristics.  The mesh should be adjusted so that there is no discernible movement  in the counter gear (the gear in the middle of the 3-gear train).

I will install the Rowan belt drive modification in the future.

Just a heads-up of some findings on my mount.

Kev
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Rob Calfee avatar
Just curious. Do you recommend the bearing replacement BEFORE the Rowan belt mod?
Götz Golla avatar
Hi Kattz,
just a coment from the practical side. I also have a HEQ5. I  put in the Rowan belt mod and I am using multistar guiding. The weight of my equipment is 12.2kg, which is just at the limit of the mount for astrophotography.
Yet I am getting a RMS guiding accuracy of mostly below 0.7arcsec, often even around 0.4arcsec.  So the mount with the Rowan belt mod is not as bad as it may seem, at least in my case.
Regards
Götz
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Rob Calfee avatar
Thanks, because I was thinking of doing the Rowan Belt mod next.
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Kevin Cummins avatar
Rob Calfee:
Just curious. Do you recommend the bearing replacement BEFORE the Rowan belt mod?

Yes.  Not replacing the bearings first might lead you to believe falsely that there might be an issue caused by the belt mod.

After polishing the worm and brass axis gears and adjusting them, the worms are butter smooth with no lash.  The drive gears still have lash, but that would contribute to guider errors, whereas the worm issues were severe enough in my opinion to cause initial off-target goto results.

I used a mixture of Super Lube grease and a tiny bit of fine valve grinding compound mixed with the grease and a cordless drill to exercise the polishing process through the worm and spur train.

There were a couple of spots in the worm mesh that felt as though someone dropped cat litter into the worm.  That is gone now.

Kev
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Kevin Cummins avatar
Götz Golla:
Hi Kattz,
just a coment from the practical side. I also have a HEQ5. I  put in the Rowan belt mod and I am using multistar guiding. The weight of my equipment is 12.2kg, which is just at the limit of the mount for astrophotography.
Yet I am getting a RMS guiding accuracy of mostly below 0.7arcsec, often even around 0.4arcsec.  So the mount with the Rowan belt mod is not as bad as it may seem, at least in my case.
Regards
Götz

I agree, Götz.  However, I think that the bearing change along with the belt mod will improve that yet again.  I have the belt mod hardware, just not added yet. 
Probably this weekend. 

I was getting 1.6-1.9 arcsec before the worm polish and bearing change even with the worm lash adjusted, but am now at around .6 arcsec without the belt mod installed yet.

I have also installed the HEQ5 to an iOptron tri-pier, and doing some other minor mount work as well.  Setting this system up for the RedCat series of OTA's, hoping that there is a RedCat 91 in the future.  I've seen some rumors on the web about it.  I have the 51 now and the 71 is on order.

Setting this up as a portable rig that I can toss in the car and go across country with.

Thanks!

Kev
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Michele Campini avatar
I bought it two years ago along with the Rowan kit.
I haven't even tried it without Rowan.
Before they invented the multi-star I drove at 0.7-0.9, now 0.4-0.6 using a setup that weighs about 11 kg.
It is an excellent mount, very strong and light and portable.
I want to suggest that you disassemble it completely and put some quality (lithium) grease in the bearings because originally the grease is of low quality and it is difficult to balance the telescope correctly.
Now I'm shooting right with her:
Michele Campini avatar
Regarding the clutch levers, they never broke for me but they are very short and annoying.
Furthermore, they must not be squeezed too tightly otherwise in the cold outside you will break your hands to open them.
So I drew them longer and 3D printed them.

https://www.thingiverse.com/thing:5074090
Neil Dunn avatar
I also replaced all the bearings in my HEQ5 with top quality Timken and SKF versions.  The belt mod was the first thing I did to it, almost from new.  There was a manufacturing issue that I discovered in the base of the RA body.  The base (the part that stays on the tripod) has had its mounting surface area painted in production which causes an uneven connection to the bottom of the RA body.  It also raises the RA body about 0.5mm above where it's designed to be, causing a small but significant alignment error between the worm shaft centre and the worm teeth centres.

I made some brass shims and fitted them under the worm gear to correct the alignment and also carefully sanded the painted surface to make it smooth.

My mount is overloaded to the point of needing an extension of the counterweight shaft of 40mm, but its performance is amazing, averaging a total RMS of about 0.5 and often in the 0.4's and rarely above 0.7.  It does seem to prefer a West heavy arrangement, but not certain about that.  It does still produce some big peaks and troughs in the guiding so perhaps these are from machining quality in the worm drives.

It is a wonderful, light weight mount indeed.

Neil
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Kevin Cummins avatar
Neil Dunn:
The base (the part that stays on the tripod) has had its mounting surface area painted in production which causes an uneven connection to the bottom of the RA body.  It also raises the RA body about 0.5mm above where it's designed to be, causing a small but significant alignment error between the worm shaft centre and the worm teeth centres.

I made some brass shims and fitted them under the worm gear to correct the alignment and also carefully sanded the painted surface to make it smooth.


I noticed that where it was line bored through the RA and DEC bearing surfaces, it was not centered, or cast correctly, and the surfaces in the bores still had paint in areas.  Fortunately, the outer bearing races fill these areas so not critical.

The design of the mount is sound, which led to my purchase of it, and I think it will be fine. 

Since it is using stepper motors like my 3D printer, I was a little surprised to see that the controller is neither RPI or Arduino-based.
Kevin Cummins avatar
I have installed the Rowan belt mod - now the mount is almost silent!

I also replaced the M10 altitude adjusting lever bolts with M10 star knobs for better control.

Waiting on the PrimaLuce saddle to be delivered this week, and then for testing to see how much things have improved with the Rowan mod!

Kevin
Ali Alhawas avatar
Michele Campini:
I want to suggest that you disassemble it completely and put some quality (lithium) grease in the bearings because originally the grease is of low quality and it is difficult to balance the telescope correctly.

I am rebuilding my atlas eq-g now with new bearings sets.. It is Rowan belt modified before 2 years..
All bearings are brand new from SKF but :
When I test all bearings with my hands they seem some kind of heavy rotation while when I tested the old bearings they are so smooth..
I supposed SKF lubricant is surely excellent but I am confused if the bearings must rotate very smooth OR its normal to feel a little heaviness when rotate it !
I need to decide before rebuilding
If someone wondering why I am changing the bearings the answer is I did all efforts to solve Dec. stiffness when clutch in released and Bad guiding in Ra. and hope that changing the bearings , shims calculations , Clean and lubrication will solve that.

Thanks
Ali
Ali Alhawas avatar
Kevin Cummins:
I will install the Rowan belt drive modification in the future.

I did Rowan belt modification to my Atlas eq-g and its away better..
strongly recommended..

Good luck
Ali
Neil Dunn avatar
Ali Alhawas:
Michele Campini:
I want to suggest that you disassemble it completely and put some quality (lithium) grease in the bearings because originally the grease is of low quality and it is difficult to balance the telescope correctly.


I need to decide before rebuilding
If someone wondering why I am changing the bearings the answer is I did all efforts to solve Dec. stiffness when clutch in released and Bad guiding in Ra. and hope that changing the bearings , shims calculations , Clean and lubrication will solve that.

Thanks
Ali

Hi Ali,
It's the tapered roller bearings in the HEQ5 that are causing most of the stiffness, but I don't know your mount to comment on that.  With Timken bearings fitted they can be tightened almost as much as you like and they won't get stiff.
Neil
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Kevin Cummins avatar
Hi, Ali,

The grease in the new bearings, if standard grease or the grease is cold, will make the bearings feel "heavy".   Heavy grease seals can also contribute to that.

For my worm gears I used ceramic bicycle wheel bearings.  They have  a low cost and almost zero resistance while being very smooth.

For the six ball bearings in the mount, I used hybrid ceramic/steel ball bearings.  High accuracy, extremely low rolling resistance.

The tapered roller bearings are by Timken and use synthetic Super Lube grease.

Good luck!

Kevin
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Ali Alhawas avatar
Thanks 
I just test my bearings now.. guess what..! 
When removing the rubber sealing from both side.. it rotate much much smoother.. What the hell is that? 
Is it normal guys?
I am thinking to use it without that rubber sealing smile
It is skf 6008 2rs1 brand new
Kevin Cummins avatar
Ali Alhawas:
Thanks 
I just test my bearings now.. guess what..! 
When removing the rubber sealing from both side.. it rotate much much smoother.. What the hell is that? 
Is it normal guys?
I am thinking to use it without that rubber sealing
It is skf 6008 2rs1 brand new

Ali, if you want to run without seals, it can cause some issues.

Not sure what the weather is like where you live, but the grease can run and get into/onto things it shouldn't like grease on the little control board in the mount without seals.

The mount can get messy and grease/optics combination is not good.

If it's fairly dry climate, you can use metal-shielded bearings and a light aircraft-grade synthetic oil (just enough to wet the surfaces) in the mount.

Kevin
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Padraic Moran avatar
Ali Alhawas:
Michele Campini:
I want to suggest that you disassemble it completely and put some quality (lithium) grease in the bearings because originally the grease is of low quality and it is difficult to balance the telescope correctly.

I am rebuilding my atlas eq-g now with new bearings sets.. It is Rowan belt modified before 2 years..
All bearings are brand new from SKF but :
When I test all bearings with my hands they seem some kind of heavy rotation while when I tested the old bearings they are so smooth..
I supposed SKF lubricant is surely excellent but I am confused if the bearings must rotate very smooth OR its normal to feel a little heaviness when rotate it !
I need to decide before rebuilding
If someone wondering why I am changing the bearings the answer is I did all efforts to solve Dec. stiffness when clutch in released and Bad guiding in Ra. and hope that changing the bearings , shims calculations , Clean and lubrication will solve that.

Thanks
Ali

Interesting because I found exactly the same with new SKF bearings. I rebuilt the RA axis with new bearings and it didn't make the difference I had expected. I haven't rebuilt Dec, and now RA and Dec guide at the same RMS 0.5-0.7". That means that if I decide to also change the bearings in Dec I risk having elongated stars.
The belt mod however did make a big difference, and I'm glad I did that.
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Kevin Cummins avatar
One thing that can be done with stiffness is to loosen the retaining grubscrews on both axes that have the tapered roller bearings and loosen the casting that presses the bearings into the races.

It's a telescope, not an axle bearing, so no need to tighten beyond the removal of excess play.  Just like a bearing used on a vehicle, tighten to "set" the bearing and then back off slightly, usually about 1/8 turn.

Don't forget to tighten the grubscrews once finished.
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Rob Calfee avatar
I did an overhaul of my HEQ5, cleaning the gears, replacing the bearings, using super lube, and added the Rowan belt mod. (Had to solder the RA connector back on after it pulled off the board when pulling the wired male connector out.) I finally got a gap in clouds to test. I went from a horrible and consistent 2 RMS and very little below that before the overhaul to .5 -.7 RMS and sometimes below .5 RMS. Amazing. I was even able to finally do a 10 minute exposure without smearing stars. I have an EQ6-r pro and will consider doing the same to it next month. Well worth it for the HEQ5. It was quite relaxing taking it apart, learning how everything worked, and putting it back together again. Cheers!
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Rajat Kumar avatar
Hello everyone here, sorry this is slightly off topic here.

I have been seriously contemplating to buy HEQ-5 as my first mount. Reading all these comments make me wonder if buying HEQ-5 makes sense. These mods/repair out of the box sound too much of an effort and expense. The other alternative i have been thinking is GEM-28. That also has issues but they sound much more manageable with no extra expense as such (at least not out of the box modification). 

Once again apologies for changing topic.

Thanks in advance.
wittinobi avatar
i think you misunderstood this.
theese are performance-mods to put your heq5 into another leage.
with the standard heq5 you may have a good solid starting mount which works very well.
and then after a few years (in my case), now im thinkink about tweaking something too.
but not because I have to, because I want to.
just my opinion.
Rajat Kumar avatar
i think you misunderstood this.
theese are performance-mods to put your heq5 into another leage.
with the standard heq5 you may have a good solid starting mount which works very well.
and then after a few years (in my case), now im thinkink about tweaking something too.
but not because I have to, because I want to.
just my opinion

Thanks. Really it's not about the discussion here. Internet is really full of how to upgrade the mount and less about out-of-the-box performance. So it gets slightly confusing. As of now I'm just doing my research and lot of overthinking. Between GEM-28 and HEQ-5, I still think latter is a better option. ​​Thanks for your reply. Will keep that in mind.
Kevin Cummins avatar
Mintakaite

Hello everyone here, sorry this is slightly off topic here.

I have been seriously contemplating to buy HEQ-5 as my first mount. Reading all these comments make me wonder if buying HEQ-5 makes sense. These mods/repair out of the box sound too much of an effort and expense. The other alternative i have been thinking is GEM-28. That also has issues but they sound much more manageable with no extra expense as such (at least not out of the box modification). 

Once again apologies for changing topic.


It's a legitimate question.  I bought the HEQ5 because it IS the better mount in my opinion for light loads up to a 102mm refractor or a carbon fiber 8" RC.  I bought mine primarily because I wanted portability and don't plan on anything larger than the RedCat 91 if and when it comes out.  The gear lash can be adjusted and you can work the current axes and adjust the mechanical tension on both to be better.  Polishing the worm helps.
The new observatory out back is housing a Paramount MX and a TMB130 refractor / 14" GSO Carbon truss RC.  This mount is to toss in the back of the Subaru when I visit my relatives out in Arizona and New Mexico.

AND, frankly it's as good as a Losmandy GM-8 with better controls.  It's better with the Rowan mods than the Titan that I converted to belts and tucked motors long before Scott thought about it.  Difference is smaller payloads.

I think you'll be happy with it, but you should understand that other than $5K mounts and up, all mounts need a little TLC and sharpening up before being perfect.

It's also sitting on an iOptron TriPier because, well, I like piers.  Not needed. Pier not in the photo below.

Here's a look at the belt vs the gears.  Note the knobs on the altitude adjustment screws.



Here it is ready for capturing photons with the RedCat 51.



Cheers!

Kev
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