Bearings for HEQ5 Pro

[cuivenion]

I'm looking to replace the bearing on my heq5 pro and I want to make sure I get the right ones. Does this list look right?

6x  6006 2RS - these are main RA and Dec shafts bearings
2x  30205  - tapered rolled bearings
4x  689z  (or 618/9) - these are small bearings for worm shafts

I've also seen the main shaft bearings given as 6006Z, and the worm bearings as 689ZZ. I just want to make sure I get the right items so any help is appreciated.

 

[cuivenion]

Any one any the wiser on this?

[bottletopburly]

The only one I know who may know is Graham on east midlands stargazers forum 

[cuivenion]

Weird would have thought a few people on here would know.

[Skipper Billy]

Here you go -

You might find this useful too....

http://www.astro-baby.com/heq5-rebuild/heq5-m1.htm

[cuivenion]

Cheers Billy, I have looked at that thread, but in another thread a different bearing model number was given and I'm trying to get a definitive answer. Although I suppose Astrobaby would know thinking about it.

[sattor]

hi there,

I changed them some months ago. I used the following bearings.

4x Roller bearing = skf  60062z 30x55x13mm

1x Tappered bearing= skf 30205j2q  25x52x16,25mm

4x small worm bearing = skf 689zz metal shielded 9x17x5mm

 

I hope that helped.

[cuivenion]

Cheers Sator.

[Stub Mandrel]

Has anyone achieved better results through a bearing swap?

They are so lightly loaded and have such a feeble duty cycle I can't see how a century of use would wear them out!

My thought is that bearing swappers put a lot of care into setting the bearings up post-swap and and this is where any gains come from.

[cuivenion]

Could be, in my case I'm getting good results with the RA and worse backlash with the dec. There was a damaged main shaft bearing in the dec that I replaced with a 6006z not zz so I'm wondering if that could be the cause. PHD2 reports thats the dec backlash is 6000ms. There's no play in the dec and I can't detect any backlash when turning the worm by hand. The dec turns quite smoothly once I have it set up.

The only thing I can think of is that the worm and worm wheel are misaligned.

[teoria_del_big_bang]

32 minutes ago, Stub Mandrel said:

Has anyone achieved better results through a bearing swap?

They are so lightly loaded and have such a feeble duty cycle I can't see how a century of use would wear them out!

My thought is that bearing swappers put a lot of care into setting the bearings up post-swap and and this is where any gains come from.

I would fully agree with this, certainly in the case of the larger bearings. I swapped mine recently but ordered all the bearings before doing the swap but if I had stripped the mount first the only ones I would have ordered were the 4 smaller bearings that are on the two worms, all the other bearings were perfectly fine.

 

For what it is worth these are all the bearings I ordered and fit.

However, I should have ordered 6 of the SKF60062RS1 not 5.

Steve

[teoria_del_big_bang]

I actually got them cheaper than the previous post. I got the bearings below from Bearings are us.

And the smaller worm bearings I got from Simply Bearings.

Steve

[sattor]

19 hours ago, Stub Mandrel said:

Has anyone achieved better results through a bearing swap?

They are so lightly loaded and have such a feeble duty cycle I can't see how a century of use would wear them out!

My thought is that bearing swappers put a lot of care into setting the bearings up post-swap and and this is where any gains come from.

Generally bearings are not likely to wear off due to the slow movement of the mount. I got mine replaced because my mount was not used for many years from the previous user and got really stiff. I made a service and replaced them because of the low cost. 

Small difference may be seen by the worm bearings.

The big difference will be, when you tune the worms perfectly. Thats the hard part. 

[Prolifics]

Does it matter what compound of metal the bearing are made of? Different toughness etc?

[cuivenion]

On 14 April 2019 at 12:37, sattor said:

Generally bearings are not likely to wear off due to the slow movement of the mount. I got mine replaced because my mount was not used for many years from the previous user and got really stiff. I made a service and replaced them because of the low cost. 

Small difference may be seen by the worm bearings.

The big difference will be, when you tune the worms perfectly. Thats the hard part. 

The the thing is though, I tune it till I can't feel backlash by hand and there's no play. The Dec  axis is rock solid but still moves smoothly but I still get significant backlash. I'm a bit baffled.

[Stub Mandrel]

1 hour ago, cuivenion said:

The the thing is though, I tune it till I can't feel backlash by hand and there's no play. The Dec  axis is rock solid but still moves smoothly but I still get significant backlash. I'm a bit baffled.

I doubt bearings can cause backlash if preloaded correctly 

How have you set the gear train?

Have you made sure there's no back/forth movement of the worm?

[sattor]

1 hour ago, cuivenion said:

The the thing is though, I tune it till I can't feel backlash by hand and there's no play. The Dec  axis is rock solid but still moves smoothly but I still get significant backlash. I'm a bit baffled.

http://www.astro-baby.com/heq5-rebuild/heq5-m1.htm

Check the above guide. Make sure that there is no movement on dec and that the gears on the side move freely.

Also check the screw on the one side of the worm (under the black cap) and make sure that the worm turns freely without sideways movement.

Check if there is big distance on the gears on the side. Turn the one gear. If you feel that you need more than 2  steps to move the next gear then you have to get the one closer to the other. The distance must be like a sheet of paper. 

Generaly there is hard work to be done and much testing.

[cuivenion]

26 minutes ago, sattor said:

http://www.astro-baby.com/heq5-rebuild/heq5-m1.htm

Check the above guide. Make sure that there is no movement on dec and that the gears on the side move freely.

Also check the screw on the one side of the worm (under the black cap) and make sure that the worm turns freely without sideways movement.

Check if there is big distance on the gears on the side. Turn the one gear. If you feel that you need more than 2  steps to move the next gear then you have to get the one closer to the other. The distance must be like a sheet of paper. 

Generaly there is hard work to be done and much testing.

Hi, done all that I'm afraid, It's belt modded as well.

[cuivenion]

39 minutes ago, Stub Mandrel said:

I doubt bearings can cause backlash if preloaded correctly 

How have you set the gear train?

Have you made sure there's no back/forth movement of the worm?

Hi, I'm pretty sure there's no worm movement (if you're talking about worm end float).

"How have you set the gear train?", I don't understand the question I'm afraid, if you're referring to the gears on the side it's a belt modded mount.

I am wondering how you preload correctly on the dec axis though. Maybe thats the problem.

Thanks for all the replies, pretty certain I'm just getting the rebuild wrong somewhere. I'm not the most mechanically minded but I like to try.

[Stub Mandrel]

1 hour ago, cuivenion said:

I am wondering how you preload correctly on the dec axis though. Maybe thats the problem. 

I carefully set up my HEQ5, but once a scope was added dec backlash appeared in spades.
I readjusted the worm clearance with the scope in place - taking care not to try and shift the whole dead weight with the adjuster screws by taking the weight with my left hand. I got much better results. This is an example calibration in CCD inspector, not perfect: