Heq5 synscan upgrade - HELP please

[long_arms]

Hello, 

I'm currently in the process of installing the synscan upgrade kit for my Heq5. 
I've only just begun and have been following the instructions religiously. 

Anyway the 2 brass gears are stuck! I've loosened both of the little allen screw thingys on both, nope. Then I've removed the allen screws completely on both gears. Yes I've removed 2 from each gear. 

Still no. They both come up so far and then stop. Won't come off completely. I've tried using pliers but it doesnt seem to be helping. 
Oh and even with those allen screws removed turning the gears by hand still moves the mount like nothings changed   . 

Thoughts? I have WD40 but not sure if that would help (I'm naff with any sort of DIY)

I can post pictures if it helps. 

Thanks  ,
Dan

[Ant]

I did a guide to the synscan upgrade but didn't come across anything that prevented the brass cogs from coming up off the posts.

http://stargazerslounge.com/topic/24782-primer-heq5-synscan-upgrade/

I seem to remember having to pull the cogs up while wiggling as they are a snug fit. But it was a while ago that I did it.

Sorry I can't be more help.

Ant

[long_arms]

Thanks Ant, 

I actually have your guide printed off next to the skywatcher instructions hehe   

I've plonked it outside to cool down for a while. 
This is incredibly frustrating as you can imagine. Cup of tea and a break now. 

Dan

[Teslar]

They are a very snug fit and any burr caused by over tightening if the grub screws or burr on the top of the spindle can prevent removal. There is a special puller available to remove the small cog. The large cog can usually be levered loose with the large screw driver. But be careful not to cause damage to the casting or spindle Try removing and burr from the top of the spindle and a little leverage. If your not comfortable there are companies out there who will do the job for you. Try Graham at Astrotec he would help and he is very good on price

[long_arms]

Okay heres an update and pictures to clearly show what the issue is. 

This is the setup before starting (bit of a pointless picture) 



I removed the motors (as the manual instructed) it then said to loosen the 2 screws on each of the brass gears and remove the brass gears. I loosened the screws, the gears wouldn't come off. 
I then removed the screws completely and since then I have tried my hardest but they still won't come off! Was removing the screws completely the wrong thing to do? Cant imagine that would be the culprit. 

I have used WD40 and the gears now move very easily along the shaft. There's just something stopping them from coming off. 
They move so easily up and down that I had to hold it as far up the shaft as it goes with my finger for the picture. 



This final picture shows both of them sat back (again a slightly pointless picture)



To conclude, with no force whatsoever I can wiggle them up and down the shafts. Just not all the way off. Thoughts?? Really at a loss here and desperate to get them off   
Can I remove the worm gear with the brass gear still attached? 

Thanks, 

Dan

[1parsec]

Hello Dan,

You're doing the right thing by taking your time and thinking about the problem, frustrating as it is.

I think the issue is from the indent made to the worm shaft by one of the grub screws.

It will be the screw position that locks directly on the side of the shaft. The other screw clamps on to the flat so no problem there.

The gears may still come off with more pulling / twisting and it may help with a screwdriver to pry from the back of the gear.

But the best tool for this situation is small set of gear pullers to jack the gear from the end of the shaft like these -

http://www.screwfix.com/p/laser-reversible-gear-puller-4-100mm/48634

Just make sure the toes of the feet are narrow enough to slide in behind the gear and casting.

Dave.

[1parsec]

Er, looking at the photos again, the may not be enough space to get the puller feet behind the gear in the 3 positions

So one trick I've used before is the grind and polish the end on the grub screw with a very slight radius and gently clamp it back in position over the marked area.

Repeat this in slightly different positions and hopefully it will squash the mark on the shaft sufficiently to remove the gear.

Dave.

[long_arms]

Thanks so much for the ideas Dave. 

I think I'll give your idea of pushing the grub screws back in, in different positions. 
The only trouble is, whilst the gears move up and down the shafts easily, they certainly don't rotate. 

I'm going to give it a few more gentle attempts. But then, since theres no need for these old brass wheels anymore, is there anything stopping me from hacksawing them off? 

I'd obviously have to be careful not to damage the casing or the shaft. Getting a bit sick of looking at it now haha   

Thanks, 

Dan

[1parsec]

Hi Dan,

I would only cut the gear off as a last resort.  It's almost impossible not to 'nick' the shaft some where or other.

How about something like this -

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_216691_langId_-1_categoryId_255216

or this sort of thing - http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_199391_langId_-1_categoryId_255216

(they are probably a bit too big but you'll get the idea)

You could drill the 2 or 3 holes in the gear and use self tapping screws to fit the triangular piece on to the gear. If you got a tap to thread the holes, even better.

A bolt screwed through the central tapped hole would jack the gear off the shaft.

Perhaps it could be just a bent piece of metal and a nut epoxied on the underside of the bracket for the central thread.

Dave.

[pete_l]

Have you tried heat?

Give them a blast with a hairdrier (not blowlamp / heatgun) and see if that loosens anything.

When heated, metals expand - and the gap between connected metals expands, too - so that should help. Also, brass expands more than steel, so the gears might just get loose enough to shift.

[Astro_Baby]

Not sure whats happening here but a bit of heat might help. Carefully...dont overdo it, the paint on the mount can come off quite easy under heat and there are plastic components around as well which migh not take heat too well.

You can remove the worms from their casings without getting these gears off from memory.

My bet is there is a bur or oerhaps a bit of swarf stuck under the brass gears on the shaft..

If these are the gear weels that willbe replaced by the kit you can affor to lose them, try getting a mole grip onto the end hubs, the bit that sticks out in the centre and twist them a bit.

Your doing the right thing b y going slow here and taking the grubs screws all the way out would have made no difference.

[Astro_Baby]

Ps, you could take the work carriers off completely, was that what you meant earlier I wonder, these are the blocks that hold the entire worm and spur gears off. They are held on by four large hex headed chrome bolts.nnwith these removed you would be able to gat a small hammer onto the back ends of these and may gently gap them off, if you do this ritate the woem round and tap a but then rotate again and so on so the force isnt all in one place.

From memory you may on the five be able to drop the entire worm out if the retaining nit on the other end is loosened off of the woem. The probalem with this approach ie remoevng the woem blocks, or the woem is the mojnt will need a retune and thats painful.

Have you had a look at my guide on stripping the five to see how its held together, my memory is not reliabel here as its been so long since i have dine anything with a five.

[long_arms]

Thanks for all the input guys, really is greatly appreciated.  The gears are OFF  ! 

The problem was as astrobaby suggested; a bur. I didn't mention it in the original post but the screws on each gear were really done up rather tight, I was bending the little allen key undoing them. 
On the flat part of the shaft, skywatcher had used the screw on the left, unfortunately the second screw was a pointed one and they had screwed it right into the shaft. There was a large bur surrounding each of these and a hole. 


 

I was running out of ideas tbh, so popped to maplin and bought some small needle files. Last night I then popped one down the tiny holes and began to try and work away the burs this way. 
I could see this was helping so continued to do this until it was almost off. Then blasted the gears with a hairdrier for a while and yanked them off the shafts with pliers. 

So relieved when the first one came off, the hairdrier broke midway through heating up the second one (typical haha  ) so required a little more force but also came off. 
As you can see from my earlier, brute force tactics I really mashed up the outside of the brass gears.



I'm going to carefully file away the burs on the shafts before fitting the new ones. 

Thanks everyone, 

Dan 

 

[long_arms]

On a side note, I noticed when the gear was still on the shaft, that the RA drive vibrated as I turned the gear by hand. 

Now the gear is off and turning the shaft by hand it really is vibrating a lot. It stops if I push into the shaft and twist.
Do I need to adjust the worm or is it something else? 

Thanks again, 

Dan

[Astro_Baby]

The vibes could be a lot of things, my bet would be its a worm tuning issue.....non GoTo mounts often seem to have thw worms pressed quite tight into the ring gears. Reason being the non GoTo motors are far more torquey than the steppers with the Goto kit....tyat allows the gearing to be tighter which makes things easier to tune. When I upgraded my own five the thing had harrendous binding issues after fitting the GoTo kit which made the mount unusable. The astro world though got an HEq5 rebuild guide as the only way I had of resolving the problems was to strip the mijnt down and find out what was going wrong.

If you take a look at my guide the last page covers worm tuning issues. Its worth having a look at the EQ 6 woem tune guide as well which covers a lot more as it was done based on a lot more experience.

Worm tuning is a monster pain but worth it to get the mount running super smooth.

The other reason for the vibration could be the worm end rollers are kancked....the worst bearings in the whole mount are the worm end bearings and usually if ai rebuild a moun I sawap them out pronto.

The other reason could be poor lubricataion...you'd have to take the worm holders off to find out for sure.

One mount I tuned had a nasty ding in its worm end rollers side whoch was causimg a fair amount of judder and vib.

Hope thats some help

[warwa]

Hi

Just came across the same problem, but with just one gear wheel  being stuck during my upgrade.  Easily fixed by reading this guide so thanks to every one who suggested fixes.

John