EQ6 RA Tuning

[Zakalwe]

Hmm....there seems to be a lot of play in my RA axis. I've got the DEC down sweet as, but when the RA clutch is locked I can "waggle" the counterweight bar back and forth by about 5 mm. I've used the AstroBaby worm adjustment guide, but when I slacken off the lower grub screw I can then tighten the upper screw all the way in (going so far that the grub screw head is below the surface of the casting by about 3 mm. Any more and it will drop inside the mount.

Any ideas?

[r3i]

I had quite a bit of play in my RA too. As it happens I spent last weekend using Astro-Baby's excellent documentation to strip down, clean, re-grease the gears and replace the worm bearings ( more on this later).

After the rebuild the play was gone, but it took a couple of attempts at adjusting the grub screws as initially I hadn't loosened the 4 hex bolts sufficiently to allow the grub screws to have an effect - so maybe you need to slacken them off a bit more when making the adjustments?

The other thing to possibly check is the locking ring at the end of the worm - perhaps this needs tightening? That is, if you're lucky enough to be able to adjust it at all - on mine it has looks like SkyWatcher have stuck it in place with superglue as it just won't budge. The DEC one was also very stiff but eventually came free. So I only managed to replace 3 of the 4 worm bearings. Still as I said the RA play has gone and there's far less chatter on the gears when the slewing ramps up and down.

Just waiting now for an elusive clear night to measure the PE to see if has improved or not.

[Zakalwe]

Thanks mike,

The locking screws were plenty loose, so thats not the issue.

it feels like worm end float. You know when you remove the black "buttons" at the end of the worms to adjust the end-float? The slotted "nut" thread was badly cut and gunked up the swarf which I have now cleaned. It won't screw in any further though.

[r3i]

it feels like worm end float. You know when you remove the black "buttons" at the end of the worms to adjust the end-float? The slotted "nut" thread was badly cut and gunked up the swarf which I have now cleaned. It won't screw in any further though.

That 'slotted nut' is the very one that I was referring to that SkyWatcher have recently been fixing into place with threadlock. Did you buy your mount new or secondhand hand? - If the latter then by the way you're describing the condition of the 'nut' it sounds like someone has had a go at adjusting it in the past and come across the threadlock problem. Perhaps it was unscrewed so far then got stuck which would account for why the worm gear would then be loose.