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Bad worm gear.


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Hello, Looking for some advice on my Dec worm gear.

Since getting my EQ5 deluxe in June, I have been having issues with tracking. I thought it was my PA, but I have found out both RA and Dec have tight spots. The Dec also has a point in every rotation of the worm that binds. 

After doing some adjustments to both I'm now happy with RA having no tight spots and very little backlash. However because Dec has issues with both the ring and worm I can't reduce the backlash as much as I would like without getting binding. 

As its only 5-6 months old should I tell FLO? My opinion from looking into this is most of the skywatcher mounts have these problems. I feel quite lucky the RA is pretty good. 

Or should I try and make a certain area of the Dec as good as possible and avoid the areas that bind? From what I have learned Dec worm normally moves a max 90 degrees. So if I mark the slow motion knob where the worms tight spot is I can set it to the opposite side before guiding. 

Regards

Danny

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11 minutes ago, Enceladus Dan said:

I can't reduce the backlash as much as I would like without getting binding

I think it will depend on what level of backlash there is. EQ5 mounts are built to a price and the QC is not the best. There will always be a little bit of play in the system, which in the case of my HEQ5 needs regular fettling. Certainly if it is excessive then contact FLO, but you probably need to quantify it first.

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10 minutes ago, Clarkey said:

I think it will depend on what level of backlash there is. EQ5 mounts are built to a price and the QC is not the best. There will always be a little bit of play in the system, which in the case of my HEQ5 needs regular fettling. Certainly if it is excessive then contact FLO, but you probably need to quantify it first.

Thank you for a fast reply, is there a way to measure it? By eye imaging a clock face the free play moves from 12 to 1 maybe just after before any movement happens. 

Thanks 

Danny

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14 minutes ago, Enceladus Dan said:

12 to 1 maybe just after before any movement happens

If it is that much backlash there is seriously something wrong. I try to tune my mount until I can 'feel' no movement - and certainly nothing I can see. Are you sure everything else is right as this seems really excessive. It maybe there is a broken gear tooth or similar if it that bad. 

You can measure the backlash using various methods and software - but if it as bad as you are describing there is no need.

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4 minutes ago, Clarkey said:

If it is that much backlash there is seriously something wrong. I try to tune my mount until I can 'feel' no movement - and certainly nothing I can see. Are you sure everything else is right as this seems really excessive. It maybe there is a broken gear tooth or similar if it that bad. 

You can measure the backlash using various methods and software - but if it as bad as you are describing there is no need.

I think it's because both the worm and ring have areas that are tighter. I can reduce the backlash but I get binding. If the worm didn't have any tight spots I could adjust more out. I'll look into proper measurements to get real figure. 

Thanks

Danny

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20 minutes ago, 900SL said:

As a possible quick fix you could try changing the worm? Not guaranteed but could work

I did think of swapping the RA and Dec worms. I read that backlash is less important in RA as it is continually driving. Just a bit daunting where I'm new to all this and wasn't sure if I would make things worse.

I did pluck up courage to remove worms and clean and re-grease them. I used geoptic  grease, the grease I found inside was really sparse and had some metal pieces in it. Probably from the gears being cut at factory. 

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Also to clarify the movement from 12 to 1 is the rotation of the worm as seen by the slow motion knob before the Dec axis moves. 

I'm not sure if that is where I'm supposed to measure free play there or at the axis. 

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I was incredulous when I opened up my Skywatcher.

Missing screws on the ring gear (I think they glued it..)

Congealed stiction grease

Aluminium swarf from the ring gear  

Pot metal poor tolerance 

Worked after I sorted it all out, shimmed, fixed and fettled. PE needed guiding.

Convinced me never to buy a Skywatcher product ever again, regardless of how good the HEQ5 Pro is ;) 

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28 minutes ago, 900SL said:

I was incredulous when I opened up my Skywatcher.

Missing screws on the ring gear (I think they glued it..)

Congealed stiction grease

Aluminium swarf from the ring gear  

Pot metal poor tolerance 

Worked after I sorted it all out, shimmed, fixed and fettled. PE needed guiding.

Convinced me never to buy a Skywatcher product ever again, regardless of how good the HEQ5 Pro is ;) 

After what I saw just by taking the worm carrier off I think I should have a go at a full strip down, clean and re-grease. Just need to courage to get on with it. I have no reservations with taking driveshafts and suspension springs out of cars, this is just that bit more delicate and I'm quite heavy handed lol. 

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10 hours ago, 900SL said:

Convinced me never to buy a Skywatcher product ever again

I think this is a little harsh. They are built to a price point, but quite a bit of SW kit is ok. Yes the mounts are a bit agricultural, but given the photo's produced they cannot be that bad. Yes, both my mounts needed some settling, but right now the 10 micron is just out of reach😆

9 hours ago, Enceladus Dan said:

I think I should have a go at a full strip down, clean and re-grease

I think you should talk to the retailer first. If it is only a few months old it should not need much more than a bit of adjustment. Set to gear is expensive and should at least work. (OK so I have stripped down every reflector scope I have before it has seen first light, but that's me being fussy).

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5 hours ago, Clarkey said:

I think this is a little harsh. They are built to a price point, but quite a bit of SW kit is ok. Yes the mounts are a bit agricultural, but given the photo's produced they cannot be that bad. Yes, both my mounts needed some settling, but right now the 10 micron is just out of reach😆

 

Not harsh.. just accurate, in my experience 🤪

As I alluded, there seem to be plenty of happy HEQ5 owners out there who get their mounts to perform well. Also plenty of satisfied Star Adventurer owners.

I am just speaking from my personal experience with the SWSA pro 2. That was basically a box of CCC, poorly assembled from pot metal components. 

The positive aspect is that it has convinced me to buy quality equipment in future. I sold the SWSA and bought a Fornax. Couldn't be happier. Well made, just works, super accurate.

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3 hours ago, 900SL said:

Not harsh.. just accurate, in my experience

Fair enough. Maybe yours was a particularly poor Friday afternoon model.

3 hours ago, 900SL said:

pot metal

This is true.

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it goes to prove how good the guys on here are, the very high standard of work they produce using overpriced under engineered inferior gear massed produced by micky mouse is amazing, well done guys. the photos that are posted here daily are brilliant.

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4 hours ago, 900SL said:

Not harsh.. just accurate, in my experience 🤪

As I alluded, there seem to be plenty of happy HEQ5 owners out there who get their mounts to perform well. Also plenty of satisfied Star Adventurer owners.

I am just speaking from my personal experience with the SWSA pro 2. That was basically a box of CCC, poorly assembled from pot metal components. 

The positive aspect is that it has convinced me to buy quality equipment in future. I sold the SWSA and bought a Fornax. Couldn't be happier. Well made, just works, super accurate.

This is the way things work in China other than a few exceptional companies (DJI, Xiaomi, etc).

"Poorly Made in China: An Insider′s Account of the China Production Game" by Paul Midler is a good read.

In a nutshell though, with few exceptions being so removed from the end user, manufacturing of a product tends to work across many many many smaller companies, usually in a specific city (each city specialising in different products). The only incentive to each small company is to do it as cheap as possible. So at the start the spec is good sometimes (not always)- casting tolerances, stainless screws maybe, good quality bearings and grease, lots of quality checks, but as time goes on, the only way the companies can compete is by reducing price. slowly components get replaced by cheaper ones, labour intensive tasks gets skipped, etc. And eventually you end up the cheapest thing that still gets them the business. It's madness, but it's the way it worked till very recently. The worst that happens for the small company is the big one they are currently contracted to stops wanting the product, but there are 100s of others that will take it - you see this all the time with china made products with many different names.

With companies like Apple working with Foxcomm and demanding and policing standards, a new model was born. DJI is one early all china company that saw the benefit of doing it 'the western way'. I think ZWO is probably another. I don't see that in Sky Watcher - it all feels very much the old school model.

This idea that 'its built to a price' is total mince. For the price of our mounts we should expect massively higher engineering quality than we get. There is just no insentive for china to provide it.

 

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Chinese manufacturing costs + handout to the local communist party boss + internal transport to the ports + international freight charges + European transport + wholesaler profit + more transport costs to dealer + profit on sales + VAT. That doesn't leave much room for the Chinese manufacturer to make any effort at all. Working conditions sound as foul as our very own, dark, satanic mills of yore. Right up to the 1960s in my own, direct experience of engineering workshops.

Mind you, the worm wheel sets I received from a famous British name would never have left China. They would have been scrapped as completely unusable. Now add in the outright lies about the materials, bearings, worm housings, claims of precision, etc. on their unchanging, propaganda website.

Hobbyists are an easy touch. "They" can add a nought to the price of everything we buy and they will always get away with it.

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8 hours ago, 900SL said:

Not harsh.. just accurate, in my experience 🤪

 I sold the SWSA and bought a Fornax. Couldn't be happier. Well made, just works, super accurate.

May I ask which Fornax model you bought? Which drive system? I asked about Fornax on here but never had a response.

I'm sick of struggling with AWR [ASCOM]. Three years and counting.
It has never found a single object on a GOTO slew. NOT EVEN ONCE!

We can go to messaging if you prefer to avoid hijacking this thread.

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7 hours ago, Peter Drew said:

@EnceladusDan.   I think the easiest mitigation of the problem will be to do as you mentioned, tune the 90 degree potion of the Dec gear that is in most use.     🙂

Thank you, at least I know that it wasn’t a stupid idea I had. I think my course of action will be to measure the backlash in PHD2 , I think I read the instructions right saying the assistant will measure it for me. From there I’ll contact FLO to see what they say, while I weigh up options I’ll adjust out as much as I can in the best potion and run some sessions to see how it goes. As my mount isn’t goto I assume I’ll use Dec axis less as I’m not slewing from target to target. 
 

If a replacement is an option I’ll need to think as my RA is pretty good and don’t fancy ending up with RA being like my Dec. 
 

thanks 
Danny

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Thanks everybody, 

I wished I had looked into the backlash sooner, being completely new I assumed it was a wear thing and being a new mount it was ready out the box and I didn’t need to check it…….. Lesson learned. 
 

it would have saved me a lot of time and stress, again being new I thought it was me and my alignment was terrible so I would spend hours trying again and again and end up just using 45 second and loose 50% of the to elongated stars. Now I adjusted RA to not bind I get 90 seconds easy. Now I’m just starting with guiding I’ll be flying and can’t wait to see how my images improve. 
 

I’ll pop back after clear skies (Saturday for me in the uk but it changes daily) with some measurements and hopefully some news. 

thanks Danny

 

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18 minutes ago, Enceladus Dan said:

Now I’m just starting with guiding I’ll be flying and can’t wait to see how my images improve.

Guiding will make the backlash issues much worse, if not taken into account properly.

RA backlash is mostly irrelevant as the RA axis is under constant motion. Balancing east heavy makes the gears touch at all times= backlash irrelevant.

DEC backlash is a problem though. If yours is really bad you nay need to purposefully polar align not perfectly to allow DEC drift to be always to one direction and set DEC guiding pulses to only happen to that direction. You may also need to abandon DEC guiding completely if you lost the Skywatcher monday morning product lottery (i did).

Another trick you can do to deal with a dodgy mount is to shoot at higher declination targets. Close to the pole you can get away with a lot of issues in the mount because the sky moves so slowly.

12 hours ago, 900SL said:

Not harsh.. just accurate, in my experience 🤪

Agree with this. My mount is embarrasingly bad and poorly designed.

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51 minutes ago, ONIKKINEN said:

Guiding will make the backlash issues much worse, if not taken into account properly.

RA backlash is mostly irrelevant as the RA axis is under constant motion. Balancing east heavy makes the gears touch at all times= backlash irrelevant.

DEC backlash is a problem though. If yours is really bad you nay need to purposefully polar align not perfectly to allow DEC drift to be always to one direction and set DEC guiding pulses to only happen to that direction. You may also need to abandon DEC guiding completely if you lost the Skywatcher monday morning product lottery (i did).

Thanks Onikkinen, your posts in my last thread helped me figure out it was my tracking and not PA, also helped me decide to go guided. 

My First try guided was able to go 5 mins OK, I do need to try properly as it was a rush and skies were no good for imaging. I will try and get out before the moon phase goes into last quarter and use the time to practice and get measurements. I might even adjust dec and re-measure same night. 

I did think of swapping worms to pass my problem to the RA as I had read its less of an issue but was worried I'd make it worse. As for the SW lottery i feel I had a small win or break even as the RA is good now I adjusted out the binding. 

For the deliberate Polar misalignment I read it and get the idea but didn't quite understand the how. I assume it's the altitude is slightly out so it corrects one direction. 

Regards

Danny

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34 minutes ago, Enceladus Dan said:

For the deliberate Polar misalignment I read it and get the idea but didn't quite understand the how. I assume it's the altitude is slightly out so it corrects one direction. 

Regards

Danny

Pretty much just that.

Just align to an error of maybe 5-10 arcmin and there should be a consistent drift to just one direction in DEC. Run guiding assistant and see which direction the drift is to and set DEC guide mode to counter that. This way in theory your DEC backlash is in check because the gears are touching like in the RA. Also this relies on DEC balance being slightly out. Perfect balance will have your DEC axis wobble between the backlash gap.

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8 hours ago, Rusted said:

May I ask which Fornax model you bought? Which drive system? I asked about Fornax on here but never had a response.

I'm sick of struggling with AWR [ASCOM]. Three years and counting.
It has never found a single object on a GOTO slew. NOT EVEN ONCE!

We can go to messaging if you prefer to avoid hijacking this thread.

Fornax LT2 Tracker, not one of the GEM's.

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