SW EQ8 R Pro Adjustment

[AstroAndy]

Being a mechanical wizard, lol, NOT, I have the following few questions.

I'm still adjusting my EQ8, the Dec. is done now, the RA nearly so. Just for my understanding.

 

The middle (set) screw on the wormgear block, other than, obviously setting the position of the block, moves the block closer to the wormwheel when loosened, reducing backlash, or further away from it when tightened (reducing binding).

The 2 adjustment screws move the wormwheel., tightening (moves wheel closer to the wormblock) both by small amounts will reduce backlash, loosening (away from the wormgear) will reduce binding Is this conclusion correct?

 

Since I'm very close, I was wondering whether I can get away without one set of screws, as the instructions say loosen / tighten all of them, ie. the middle set screw, and the outer adjustment screws.

Visualizing this in my mind, I should only need to work with one (set of) screw(s) for small amounts, and not all of them to create a push-pull effect on the whole assembly.

Is this correct, and if not, what is the reasoning behind loosening / tightening all of them, when I only need one correction.

 

In Dec., there is a block that the dec. wormgear is held to (bolts have to be loosened slightly and retightened after adjustment).

1. This has a tightening effect on the final adjustment, correct?
2. This is not the case on RA, RA does not have a block its wormgear is connected to, so no bolts to undo, correct?

 

Additionally, are there any diagrams on the whole assembly (wormblock and wormwheel), where one can see the interplay between these elements and screws?

Any input would be appreciated.

[Stuart1971]

In this order. You need to loosen the centre one and then turn the  outer two a very small amount clockwise the same amount on each, then re tighten the centre one, if needing to close the gap.

Then if need to enlarge the gap you should loosen the outer two then turn the the middle one a small amount clockwise, then re tighten the outer two, again in that order…

so no you don’t need to loosen all three at the same time, as when the outer 2 are loose, the middle one will be anyway, as that only pushed against the worm block, it’s not screwed in to it.. same when you loosen the middle one, the outer 2 will be looser…

The outer two screws are threaded into the worm block, the middle one just pushed against it…

 

Edited January 23 by Stuart1971

[AstroAndy]

Hi Stuart

Thanks, that's the explanation I needed.

I'd noticed just loosening the middle (set) screw seems to have a tightening effect, and so was wondering whether, for very small increments, that's the only one I needed.

[Stuart1971]

2 hours ago, AstroAndy said:

Hi Stuart

Thanks, that's the explanation I needed.

I'd noticed just loosening the middle (set) screw seems to have a tightening effect, and so was wondering whether, for very small increments, that's the only one I needed.

Yes loosening the middle one will allow the outer two to pull in very slightly and hence tighten the worm block, as the centre one is the push screw…👍🏻

[Stuart1971]

Another good test for checking the binding on these mints I found, was putting a power supply on them with an amps reading, then when slewing when you hit a tight spot on the worm you will see the amps increase, this is a good indication to see how tight it is in places around the worm, I found it was around 1.5amps, and went up to 2.1 amps when hitting the tight spots,  it’s very obvious, the trouble with these mounts is that the large worm wheels are not perfectly round, and hence you get tight spots, so you can only set the worm gap or backlash while at the tightest spot, if not it will bind when it hits the tight spot, it took me ages to sort mine, and even then the best I could get was 2000ms of backlash, down from 3600ms

In the end I just used to guide in one direction only, then this made the lash issue moot, as the mount never changed direction in DEC

[AstroAndy]

Yeah, that's what I have done, I get about the same values, 2.1 amps is the threshold. The dec. went well, at the tightest spot I'm down to is 287ms or thereabouts. RA is almost there, I want to get it just so.

Strangely enough, my values are similar to yours, initially, 3000ms of backlash, now an average of about 1350ms (287 - 2400). This is on dec. Normally, I'd have left RA alone, but the guy I had "fix" it fixed the RA too, too well, nlol.

Edited January 24 by AstroAndy